Evolution of the Karaha-Telaga Bodas Geothermal
System based on the Composition of Alteration
Minerals
Emma Grace McConville
GEOL 394
November 25th, 2015
Advisors:
Dr. Philip Candela
Dr. Philip Piccoli
Dr. Joseph Moore (University of Utah)
ABSTRACT
The Karaha-Telaga Bodas vapor-dominated geothermal system is located on the flank of
the active Galunggung volcano in West Java. This study focuses on the epidote-bearing mineral
assemblages in the system and the chemical reactions that produce epidote. Compositional
variability in hydrothermal epidote has been attributed to a number of possible factors including
original bulk rock composition, fluid chemistry, water to rock ratios, and variations in temperature
and pressure. This study aims to evaluate whether the chemical composition of epidote is influenced
by: (1) the composition of associated plagioclase, (2) distance from veins, (3) depth, and (4) original
bulk rock composition. This study will uses energy dispersive spectroscopy, wavelength dispersive
spectroscopy, X-ray diffraction, and mathematical modeling to facilitate the identification of
influential variables that determine the production and variation in the composition of epidote in the
Karaha-Telaga Bodas geothermal system. Measurements from eight samples indicate that
composition of epidote is not positively or negatively correlated to the composition of associated
plagioclase, distance form veins, or depth.
A major unanswered question regarding hydrothermal alteration in geothermal systems
involves the production or destruction of ferric iron, a major constituent of epidote. I calculated a
model ferric iron concentration in the unaltered basalt from whole rock geochemistry and modal
phase proportions. This can be used to calculate a hypothetical modal (volume) proportion of epidote
in altered rocks, which can be compared with the volume percent of epidote from point counting.
Based on a prediction the ferric iron content of the basalt due to ferric iron concentrations in
magnetite and plagioclase is Fe2O3 0.654 wt%, hypothetical volume percent of epidote was between
5.05 and 8.14 volume percent. Point counting was done on an altered sample yielding 5.27 volume
percent ± 1.4%. Under the assumption that alteration fluid was not oxidizing or reducing the
hypothetical volume percent of epidote predicted by the model corresponds to the volume percent
measured via point counting.
TABLE OF CONTENTS
IV. INTRODUCTION AND BACKGROUND…………………………………………………...1
Karaha-Telaga Bodas Geothermal Field and Galunggung Volcano…...………………..1
Hydrothermal Minerals of Interest..……………………………………………………...5
Equalities of Chemical Potential Involving Epidote……………………………………...6
Reactions…………………………………...……………………………………...6
V. OBJECTIVES OF RESEARCH AND BROADER IMPLICATIONS………………………10
Hypothesis……………………………………………………………………………….10
VI. METHODS USED FOR ANALYSIS……………………………………………………….11
Electron Probe Microanalyzer (EPMA)………………………………………………...11
Statistical Tests for EPMA………………………………………………………12
Box and Whisker Plots…………………………………………………....12
Median Absolute Deviation………………………………………………12
Simple Regression Analysis……………………………………………....12
X-Ray Diffraction (XRD)………………………………………………………………..14
Statistical Tests for XRD………………………………………………………...14
Thin Section Images……………………………………………………………………..15
Image Analysis: Point Counting………………………………………………………...15
Plagioclase and Magnetite Model: “Plag+Mag Model”……………………………….16
(1) Potential relationship between the chemical composition
of plagioclase and epidote…………………………………………………………..16
(2) Proximity to veins…………………………………………………….........................17
(3) Depth…………………………………………………………………………………17
(4) Original Rock Composition………………………………………………………….17
VII. PRESENTATION OF DATA AND DISCUSSION OF RESULTS………………………...18
Data from EPMA………………………………………………………………………...18
(1) Chemical composition of plagioclase with respect to epidote……………….18
(2) Proximity to veins…………………………………………………………….20
(3) Depth………………………………………………………………………....20
Composition of Epidote, Chlorite, and Amphibole in T-2………………………..23
X-Ray Diffraction Spectroscopy………………………………………………………....24
“Plagioclase + Magnetite” Model Calculation……………………………………….....25
Fe2O3 in the Whole Rock from Magnetite and Plagioclase………………………25
Fe2O3 from Magnetite…………………………………………………………...26
Fe2O3 from Plagioclase………………………………………………………....27
Total wt % of Fe2O3 in Rock Due to Magnetite and Plagioclase…………….......28
Epidote Production……………………………………………………………… 29
Image Analysis Using EDS……………………………………………………………...30
VII. SUMMARY AND CONCLUSION………………………………………………………....33
VIII. BROADER IMPACTS AND SUGGESTIONS OF FUTURE WORK…………………….35
IX. ACKNOELEDGEMENTS…………………………………………………………………..36
X. REFERENCES………………………………………………………………………………..37
Appendix A: Method for Deriving Statements of Equilibria by J.B. Thompson Jr…………...….40
Appendix B Thin Section Scans (optical)…………………………………………………….….46
Appendix C: Representative Energy Dispersive Spectroscopy Images……………………….....47
Appendix D: Wavelength Dispersive Spectroscopy Data for Epidote, Chlorite, Plagioclase, and
Amphibole………………………………………………………………………………………..49
Appendix E: Hypothesis Testing for a Simple Linear Regression Model for Measuring the
Molar Ratio of Fe/Al in Chlorite and Epidote with Respect to Distance from Vein…………….68
Appendix F: X-Ray Diffractograms……………………………………………………………..70
Appendix G: Honor Code……………………………………………………………………….76
1
IV. INTRODUCTION AND BACKGROUND
Karaha-Telaga Bodas Geothermal Field and Galunggung Volcano
Karaha-Telaga Bodas is a vapor-dominated geothermal system located on the southeast
flank of the Galunggung volcano in West Java, Indonesia. The Karaha-Telaga Bodas geothermal
system is located near a subduction zone, and has characteristics that make it distinct from other
geothermal systems in extensional basins, such as those found in the western United States, and
caldera systems, which can be found in Yellowstone.
Galunggung volcano is one of the island arc volcanoes generated by the subduction of the
Australian plate under the Eurasian plate. According to Moore and others (2008) and Bronto
(1989) the Galunggung volcano comprises the Galunggung Group that encompasses the Old
Galunggung Formation, the Tasikmalaya Formation, and the Cibanjaran Formation overlying a
granodiorite basement. The Galunggung Group consists of basaltic pyroclastic flows, lahars, and
lava flows that are dated between 50,000 to 100,000 years (Bronto, 1989) (see Table 1).
Table 1. Composition of representative Galunggung volcanic rocks Old Galunggung Caldera
Formation
1822 1894 1918
Sample 20258 20270 L27-2 20288 20344 20353 20342 VB30A 20246 4-AK
Major
elements
(wt %)
SiO2 47.06 49.67 52.33 56.88 51.25 55.02 51.08 55.50 52.61 55.11
TiO2 0.87 1.03 0.94 0.84 0.96 0.71 0.90 0.72 0.81 0.83
Al2O3 15.67 20.74 19.15 18.96 18.75 18.75 18.66 18.07 19.41 19.15
Fe2O3* 9.45 9.62 8.79 7.66 9.58 7.58 9.38 8.19 8.84 7.97
MnO 0.26 0.19 0.17 0.12 0.16 0.17 0.19 0.16 0.17 0.14
MgO 10.32 4.38 4.82 3.21 5.80 4.37 5.00 4.56 4.01 3.47
CaO 11.26 10.85 9.59 7.66 10.21 8.45 10.15 8.47 9.98 8.17
Na2O 1.46 2.99 3.29 4.29 3.18 3.18 2.66 3.54 3.31 3.95
K2O 0.56 0.37 0.56 0.71 0.52 0.68 0.38 0.70 0.37 0.59
P2O5 0.11 0.13 0.18 0.19 0.14 0.18 0.16 0.16 0.15 0.17
LOI 1.54 0.52 -0.25 -0.44 -0.20 0.56 0.74 -0.10 0.54 -0.04
Total 98.56 100.49 99.93 100.08 100.35 99.65 99.30 99.97 100.20 99.51
The Karaha-Telaga Bodas geothermal system has evolved over time from an over-
pressurized liquid-dominated system to a vapor-dominated system at present. This change was
presumably caused by the collapse of the southeast flank and the depressurization of the liquid-
dominated geothermal system at approximately 4,200 ± 150 years BP (Moore and others, 2008;
Bronto, 1989). Fluid flow through the system is dominantly controlled by fractures that are the
consequence of the present day strike-slip stress regime (Nemčok and others, 2007).
Moore and others (2008, 2004a) have studied the present temperatures, pressures and fluid
composition in the Karaha-Telaga Bodas geothermal field, and have categorized four distinct
mineral assemblages that characterize the evolution of the geothermal system. The early stage
mineral assemblage reflects the mineralogy of the liquid-dominated system and is identified by the
presence of epidote, illite, actinolite, biotite and tourmaline. The early stage mineral assemblage
Fe2O3* all iron is considered ferric. Data from (Bronto, 1989).
2
includes plagioclase grains with compositions ranging roughly from 50 to 92 percent anorthite
(Bronto, 1989). The following stage reflects a mineral assemblage that is characterized by
amorphous silica, quartz, and chalcedony from boiling of fluids. The third stage mineral
assemblage reflects the inflow of steam-heated water and the deposition of calcite, anhydrite and
wairakite. The fourth stage represents a mineral assemblage of salts (NaCl, KCl, and FeClx) on the
surface of the rocks. Figure 4 indicates the depth of the first appearance of specific minerals. This
study will focus primarily on the mineral epidote in the first mineral assemblage.
Table 2. Minerals identified in samples
Depth
(m)
Ep Chl Amp Pl Qz Ilm Ttn Ilt Rt Py Hem/
Mag
Ccp Cal Afs Ap Fl Brt Wrk
396 x* x* x* x x x x+ x x x
888 x* x* x* x x x+ x x x x x x+
961 x* x* x* x x x x x x x x
980 x* x* x* x x x x x x x
1,044 x x x x x x x+ x x x x
1,193 x x x x x x x x x
1,249 x x* x* x x x x x x
1,378 x x* x* x x x x x x
Figure 1. Map of Java, Indonesia. The square indicates the location of
Galunggung Volcano where the Karaha-Telaga Bodas geothermal system is
located. (from Moore and others, 2008).
Ep = epidote; Chl = chlorite; Amp = amphibole; Pl = plagioclase; Qz = quartz; Ilm = Ilmenite; Ttn= titanite; Rt =
rutile; Hem = hematite; Mag = magnetite; Ccp = chalcopyrite; Cal = calcite; Afs = alkali-feldspar; Ap = apatite;
Fl = fluorite; Brt = barite. Phases identified by using EDS, *WDS, +X-Ray Diffraction.
3
Figure 2. Topographic map of Galunggung Volcano.
Drill cores, crater, fumaroles, thermal springs, and lakes
are labeled (from Moore and others, 2008).
Figure 3. North-south cross section of region in Figure 2 of a conceptual model of the Karaha-
Telaga Bodas geothermal field with labeled drill cores (modified from Moore and others,
2008). Solid horizontal lines in the subsurface represent the temperature measured, the
dashed lines are inferred temperatures. Green line represents the presence of epidote.
4
Figure 4. North to south cross section of Karaha-Telaga Bodas geothermal system. Black solid lines indicate
the first appearance of minerals of interest. (A) First appearance of smectite, smectite-illite, and illite. (B)
First appearance of epidote, actinolite, biotite, and tourmaline. The top of the propylitic zone is defined by
the first appearance of epidote. In sample 396 m epidote is present above the stated epidote surface Moore et
al. (2008) defines. (C) First appearance of anhydrite and wairakite (from Moore and others, 2008).
5
Hydrothermal Minerals of Interest
Understanding the factors that affect the chemical composition of epidote provides insight
into the complex dynamics of the hydrothermal system over time, and has implications for
developing geothermal energy production. Epidote is an important mineral to study because it is
one of the few minerals that contains ferric iron as an essential structural constituent. The chemical
variation of epidote can provide insight into the history of the temperature, pressure, permeability
and fluid chemistry of the geothermal system, if properly interpreted (Browne, 1978; Giggenbach,
1981; Henley and Ellis, 1983; Bird and others, 1984; Reyes, 1990; Absar, 1991; Reed, 1994;
Muramatsu and Doi, 2000; and Bird and Spieler, 2004). Epidote has been found in hydrothermal
systems at temperatures greater than 200⁰C, but it is most often found in altered volcanic rocks
between 230⁰C and 260⁰C (Bird and Spieler, 2004). The range of temperatures, pressures, and
thermodynamic chemical potentials have been determined through experimental data, fluid
inclusion analysis, isotopic composition analysis of coexisting phases, stratigraphic reconstruction,
and the thermodynamics of mineral assemblages (Bird and others, 1984).
Hydrothermal epidote forms in veins and vugs and can replace carbonates, iron-oxides,
and silicates (Bird and Spieler, 2004). Epidote can also form as a product of volcanic glass
alteration, leaving behind an altered groundmass with relatively unaltered mineral grains (Figure
5) (Moore and others, 2008). Variability of Fe3+/Al3+ in hydrothermal epidote has been attributed
to a number of possible factors, including hydrothermal oxidation and carbonation reactions, bulk
rock composition, fluid chemistry, fluid to rock ratios, and variations in temperature and pressure.
However, the principle factors thought to affect the chemical composition of epidote are bulk rock
and fluid composition (Bird and others, 1984, 2004; Shikazono 1984).
This study investigates the chemical variations of minerals associated with epidote that
exchange iron and aluminum to determine their ability to limit or enhance the production, and
chemical composition, of epidote. For example, epidote in the presence of hematite has been found
to contain more iron and less aluminum compared to epidote found with prehnite, pyrite, and
pyrrhotite (Shikazono, 1984). Additionally, statements of equilibria involving epidote, chlorite,
prehnite, titanite, and rutile can be used to understand the complexities of alteration. Following the
method outlined by J.B. Thompson (1982) statements of equilibrium (equalities of chemical
potential of phase components) were derived that describe the chemical composition of epidote
and associated mineral phases (see Appendix A; Thompson, 1982). By using J.B. Thompson’s
(1982) method of deriving statements of equilibrium, the number of independent equilibria is the
Figure 5. Plane polarized light images (left), cross polarized
light image (right) of sample at 396 m.
6
difference between the number of phase components and the system components present. The
number of statements of equilibrium derived from the original matrix represent the number of
linearly independent statements of equilibrium that can be perturbed to produce a chemical
reaction. If the number of independent equilibrium is more than one, the statements of equilibrium
can be added and subtracted from one another to form additional statements of equilibrium. Only
when petrographic analysis is done and the relationship between minerals is described can one
determine which statements of equilibrium have been perturbed (change in temperature, pressure,
introduction of a new phase) to produce a chemical reaction.
In the following section, the statements of equilibrium were derived following the method
outlined by J.B. Thompson (1982) and are assumed to be perturbed, and therefore can be treated
as chemical reactions. In geothermal systems, such as the Karaha-Telaga Bodas geothermal
system, variations in aqueous fluid composition define the variables that perturb the system. The
composition of the mineral phases and the presence of certain mineral assemblages will provide
insight into the chemical reactions that have occurred in the Karaha-Telaga Bodas geothermal
system.
Equalities of Chemical Potential Involving Epidote
The chemical composition of epidote is a reflection of the mineral assemblage and the bulk
rock composition of the rock at a given temperature and pressure. This section describes some of
the continuous and discontinuous reactions that involve epidote based on the phases identified by
using a combination of polarized light microscopy and Energy Dispersive Spectroscopy (EDS)
(see Table 2) and phases Moore and others (2008) identified in the Karaha Telaga Bodas
geothermal system. These phases include: actinolite, calcite, chlorite, clinopyroxene, epidote,
plagioclase, prehnite, quartz, and titanite. Only a few of the aforementioned phases are found
together in each sample. Identified phases are used to algebraically derive balanced chemical
reactions by using J.B. Thompson Jr.’s (1982) methodology. These reactions do not occur in
isolation, but serve as a guide to understand the reactions that may occur with phases present.
Exchange components will be used instead of explicit phases to best generalize and not limit the
scope of the reaction. By identifying mineral assemblages in each of the samples (see Table 2)
and measuring the chemical composition of each phase, I identified chemical reactions that
contribute to the chemical composition of epidote in in the Karah-Telaga Bodas geothermal
system. In particular, I was interested in the changes in Fe/Al ratio in epidote and associated phases
and the Fe/Mg ratio changes in phases associated with epidote. Below are some of the chemical
reactions that could be taking place in the Karaha-Telaga Bodas geothermal system.
Reactions 18CaAl2Si2O8 + 34H2O + 6CaFeSi2O6 + 18Fe3O4 = 12Ca2Fe3Si3O12(OH) + 7Fe6Si4O10(OH) + 2SiO2 + 18Al2Fe-1Si-1
This reaction represents the hydrothermal alteration of a clinopyroxene-rich basalt. In this
reaction the iron-end-member of clinopyroxene, hedenbergite, alters and provides calcium for
pistacite production and ferrous iron for the production of the iron-end-member of chlorite.
Additionally, the calcium in the anorthite end-member of plagioclase is used in the production of
pistacite. Note, that the molar volume of pistacite produced is greater than three times the amount
of chlorite produced. In this reaction, magnetite is the only reactant that supplies ferric iron for
(An) (Hd) (Mag) (Ep) (Fe-chl end-member) (Qz)
7
the production of pistacite. Aluminum from the consumed plagioclase produces the Al2Fe-1Si-1
exchange component for chlorite; as the reaction proceeds to the right the chlorite becomes more
aluminum-rich at the expense of silica and iron.
4CaAl2Si2O8 + 13H2O + 11
2Fe2SiO4 + 3Fe3O4 +
1
2SiO2 = 2Ca2Fe3Si3O12(OH) + 3Fe6Si4O10(OH)8 + 4Al2Fe-1Si-1
This reaction represents the hydrothermal alteration of an olivine-rich basalt, or its glassy
equivalent. In this reaction there is no oxidation or reduction of iron. If the reaction proceeds from
left to right the ferric iron in magnetite is used to form the iron-end-member of epidote, pistacite.
The ferrous iron in the olivine iron-end-member, fayalite, will produce the iron-end-member
chlorite. The plagioclase provides the calcium in pistacite and the aluminum in the exchange
component Al2Si-1Fe-1 in the chlorite. The mole fraction ratio of pistacite to iron-end-member
chorite produced is two to three. As the reaction proceeds to the right the chlorite becomes more
aluminum-rich at the expense of silica and iron. In this reaction quartz is the limiting, the presence
of quartz is necessary for the production of pistacite and chlorite.
CaFe2Si2O8 + 16
3SiO2 + 2Fe3O4 +
7
3H2O = 2Ca2Fe3Si3O12(OH) +
1
3Fe6Si4O10(OH)8
If the reaction proceeds for left to right, the ferric iron in the iron-end-member of
plagioclase and the ferric iron in magnetite will be used to produce pistacite. The calcium from the
iron-end-member of plagioclase will provide the calcium for the pistacite. The ferrous iron
required to produce the iron-end-member of chlorite will come from the single ferrous iron site in
the magnetite. The modal proportion of pistacite to the iron-end-member of chlorite is six to one.
According to Bronto (1989) the Galunggung volcano comprises of basaltic rocks that
predominantly contain plagioclase, olivine, pyroxene, and magnetite. The ferric iron in the
unaltered Galunggung rocks come from plagioclase and magnetite (Lungaard and Tegner, 2004).
This reaction provides insight into the potential alteration of phases like plagioclase and magnetite
in the Galunggung basalt protoliths.
Fe5Al2Si3O10(OH)8 + SiO2 + 4
3 CaTiSiO5 =
1
3 H2O +
2
3 Ca2Al3Si3O12(OH) +
4
3 TiO2 +
5
6 Fe6Si4O10(OH)8
If this reaction proceeds to the right, chamosite reacts with quartz and titanite to produce
water, clinozoisite, rutile, and a less aluminum-rich iron end-member of chlorite. The more
aluminous chlorite will be lighter in color than the less aluminous chlorite on the left. As identified
in the previous equation, titanite serves as a calcium buffer. Free water on the right side of the
reaction indicates a dehydration reaction brought on by increasing temperature.
Ca2Al3Si3O12(OH) + 7
12Fe6Si4O10(OH)8 +
7
6SiO2 = Ca2Fe5Si8O22(OH)2 +
11
6H2O +
3
2Al2Si-1Fe-1
(Chm) (Qz) (Ttn) (Czo) (Rt) (Fe-chl end-member)
(Czo) (Fe-chl end-member) (Qz) (Fac)
(An) (Fa) (Mag) (Qz) (Ep) (Fe-chl end-member)
(Fe-pl end-memeber ) (Qz) (Mag) (Ep) (Fe-chl end-member)
8
If the reaction proceeds to the right, clinozoisite, the theoretical iron-end-member of
chlorite and quartz will react to produce ferroactinolite, water, and exchange component Al2Si-1Fe-
1. The exchange component Al2Si-1Fe-1 influences the chemical composition of chlorite and
actinolite. On the right side of the reaction the exchange component Al2Si-1Fe-1 influences the
chemical composition of actinolite and chlorite by making them more aluminum-rich. Note again
that the exchange between iron and magnesium is not explicitly stated, however, it is present in
this reaction. The volume of clinozoisite, iron-end-member chlorite, and quartz decrease and the
volume of actinolite increases. If the reaction proceeded to the left, the ferrous iron in the
ferroactinolite would not be oxidized and consequently there would be no exchange reaction
between aluminum and iron in the clinozoisite. However, other ongoing reactions could facilitate
an increase in Fe/Al in the epidote.
Ca2Al2Si3O10(OH)2 + Al2Si-1Mg-1 + SiO2 + FeAl-1 = 1
2H2O + FeMg-1 +
1
4O2 + Ca2Al3Si3O12(OH)
This continuous reaction has an additive component of oxygen and exchange components.
The Al2Si-1Mg-1 and FeMg-1 exchange components operate in chlorite, whereas the FeAl-1
exchange component operates in chlorite, epidote, and prehnite. If the reaction proceeds to the
right, as a reduction reaction, the ferric iron content in chlorite and epidote. The volume of epidote,
prehnite, and quartz decreases and oxygen and water are produced. The chlorite becomes less
aluminous and its iron increases with respect to magnesium. The effect of oxygen as a product of
this reaction is the reduction of ferric iron in epidote and to a lesser extent in prehnite and chlorite
to ferrous iron in chlorite. The production of water in this reaction indicates a net mass transfer
from prehnite to epidote. If this reaction were viewed in isolation one would see a decrease in the
volume of prehnite and an increase in the volume of epidote. Additionally the epidote would
become a paler green in color and the chlorite would not appreciable change in volume, but it
would become darker in green color.
Mg5AlAlSi3O10(OH)8 + 12FeMg-1 + 3O2 = 4H2O + 10SiO2 + 12FeAl-1 + 7Al2Si-1Mg-1
Clinochlore is the magnesium end-member of the chlorite group. In this reaction the Al2Si-
1Mg-1 and FeMg-1 exchange only occurs in the chlinochlore phase and the FeAl-1 exchange occurs in
epidote (and prehnite if present). If the reaction proceeds to the right as an oxidation reaction,
clinochore will react and become more magnesium-rich relative to iron. Additionally, the
magnesium and silica in the chlorite will exchange for two aluminum atoms. Consequently the
chlorite will be more aluminous and lighter in color and the Fe/Al ratio will decrease in chlorite.
The ferrous iron in the FeMg-1 is oxidized to produce ferric iron, which is represented in the FeAl-
1 exchange component. Epidote (and prehnite if present) will be greener in color and have a higher
Fe/Al ratio.
Ca2Fe3Si3O12(OH) + SiO2 + 3
2H2O + 2TiO2 = 2CaTiSiO5 +
3
4O2 +
1
2Fe6Si4O10(OH)8
If the reaction proceeds to the right, the epidote end-member pistacite reacts with quartz,
water, and rutile to produce titanite, oxygen and a theoretical iron end-member of chlorite. The
(Prh) (Qz) (Czo)
(Clc) (Qz)
(Ep) (Qz) (Rt) (Ttn) (Fe-chl end-member)
9
oxygen is an external intensive variable in this reaction. Proceeding from left to right, this is a
reduction reaction. If the reaction proceeds from right to left, it is an oxidation reaction, and the
ferrous iron is oxidized to form ferric iron. During oxidation, the volume of pistacite increases at
the expense of the volume of the iron end-member of chlorite. In this reaction, the sub-assemblage
rutile+quartz+titanite can serve as a calcium buffer that can consume or supply the calcium in the
system. In drill core T-2, titanite may have formed from TiO2 in volcanic glass or from rutile in
the lava flow, but it is not an original igneous phase in the parent Old Galunggung Formation.
Ca2Fe3Si3O12(OH) + 1
3 Fe6Si4O10(OH)8 +
11
3 SiO2 = Ca2Fe5Si8O22(OH)2 +
5
6 H2O +
3
4 O2
If the reaction proceeds to the right as a reduction reaction, pistacite will react with a
theoretical iron-end-member chlorite and quartz, to produce ferro-actinolite, water, and oxygen.
The ferric iron in pistacite will be reduced to produce ferrous iron in ferro-actinolite. Ferro-
actinolite will increase in volume at the expense of the pistacite, the iron-end-member of chlorite,
and quartz. If the reaction were to proceed to the left as an oxidation reaction, the volume of ferro-
actinolite would decrease and the volume of pistacite, iron-end-member chlorite, and quartz would
increase. The production of ferro-actinolite without the production of tremolite suggests a high
Fe/Mg molar ratio in actinolite and chlorite. If the reaction proceeds to the right there is an increase
in temperature and the pistacite and chlorite will be dehydrated. In geothermal systems, actinolite
first appears between 280° to 300°C (Brown, 1978). The bottom hole temperature of drill core T-
2 is 321°C (Moore and others, 2008). Although the exchange FeMg-1 is not explicitly stated in the
reaction, actinolite and chlorite can participate in the exchange. With increasing metamorphic
grade, chlorite generally becomes more magnesium rich (Aranson et al., 1993).
1
4 O2 +
1
2 H2O + CaFeSi2O6 + CaAl2Si2O8 Ca2Al2FeSi3O12(OH) + SiO2
Hedenbergite, anorthite, water and oxygen react to produce epidote and quartz. This
reaction is a discontinuous reaction. This reaction describes one way that epidote can be produced
from minerals in a basalt by hydrothermal alteration. Additionally, oxides in basaltic glass can
react with one another to produce epidote and other hydrothermal minerals.
3Ca2Al2Si3O10(OH)2 + 2CO2 = 2Ca2Al3Si3O12(OH) + 3SiO2 + 2H2O + 2CaCO3
If the reaction proceeds to the right, prehnite reacts with carbon dioxide to produce
clinozoisite, quartz, water, and calcite. Although it is not explicitly expressed in this reaction, there
is an exchange between aluminum and iron in prehnite and in epidote (clinozoisite). During this
reaction prehnite decreases in volume, while clinozoisite and calcium carbonate increase in
volume. The production of clinozoisite (epidote) is dependent on the ratio of moles of prehnite to
moles of carbon dioxide, 3 to 2, respectively. The amount of clinozoisite (epidote) produced will
be dependent on the relative amount of prehnite and carbon dioxide present in the system.
(Prh) (Czo) (Qz) (Cal)
(Ep) (Fe-chl end-member) (Qz) (Fac)
(Hd) (An) (Ep) (Qz)
10
V. OBJECTIVES OF RESEARCH AND BROADER IMPLICATIONS
In this study I determine whether the variation in the composition of epidote (principally
along the FeAl-1 exchange vector) in samples from drill core (designated as T-2) can be attributed
to (1) the chemical composition of associated plagioclase, (2) proximity to veins, (3) depth and (4)
original bulk rock composition. Hydrothermal alteration is the principal mechanism for producing
epidote in this geological setting. The ratio of iron to aluminum in epidote is reported herein in
terms of the mole fraction of pistacite, Xps = Fe3+/(Fe3++Al3+).
Plagioclase is a calcium bearing phase and can be a reactant in the production of epidote.
Plagioclase grains are relatively unaltered compared to the groundmass in each sample. In samples
with calcic plagioclase there could be more epidote, holding all other variables constant. The mole
fraction of anorthite was measured and compared to the mole fraction of pistacite in each sample.
Veins are the principal mechanism of fluid transport in the Karaha-Telaga Bodas
geothermal system (Nemčok and others, 2007). The water to rock ratio contributes to the alteration
of the host rock and consequently influence the production of epidote. Variability in the
composition of the epidote with respect to distance from vein may provide insight into the
water/rock ratio and fluid chemistry of the geothermal system. Depth is a proxy for temperature,
and according to Aranson and others (1993), epidote becomes more aluminum-rich with increasing
temperature. Sikazono (1987) attributes the original bulk rock composition as the dominant factor
that effects the ratio of Fe/Al in epidote. Simultaneously, the composition of iron bearing phases
like actinolite, and chlorite were been analyzed in order to examine the relationship in each
assemblage.
Hypothesis:
The mole fraction of pistacite (Xps) in epidote is a function of:
(1) The chemical composition of associated plagioclase,
(2) Proximity to veins,
(3) Depth, and
(4) Original bulk rock composition.
11
VI. METHODS USED FOR ANALYSIS
Eight thin sections from eight different depths in the T-2 drill core (396 m, 888 m, 961 m, 980
m, 1,044 m, 1,193 m, 1,249 m and 1,378 m) were analyzed by employing optical microscopy,
Energy Dispersive Spectroscopy (EDS) and wavelength dispersive spectroscopy (WDS). The
JXA-8900 SuperProbe at the University of Maryland was used to determine the phases in each
sample and the chemical composition of epidote, plagioclase, chlorite and amphibole. X-Ray
Diffraction (XRD) was performed on six samples by Frank Dulong at the USGS in Reston,
Virginia.
Electron Probe Microanalyzer (EPMA)
A JEOL JXA-8900 SuperProbe electron probe microanalyzer was used to determine the
chemical composition of phases present in the thin sections. During the operation of the EPMA,
the tungsten filament was heated and electrons were emitted. An anode plate situated below the
tungsten filament applied an accelerating voltage to the electrons, and the beam was magnetically
focused. The beam of electrons, with a diameter of 1 to 3 µm, interacts with the sample by
removing electrons primarily from the innermost shell (K-shell or n=1 shell) producing an electron
vacancy and an unstable configuration. An electron from an outer shell moved to fill the vacancy,
which in turn produces an x-ray of the element being analyzed, with a characteristic energy and
wavelength. In Energy Dispersive Spectroscopy (EDS), an energy filtering spectrometer counted
the number of x-rays produced at specific energy bins, and those correspond to characteristic
energies for each element (above a certain minimum energy; H, He, Li, Be cannot routinely be
detected). In the case of Wavelength Dispersive Spectroscopy (WDS), a crystal with a known d-
spacing is located between the sample and the x-ray counter, and the crystal rotated in order to
satisfy Bragg’s law, nλ = 2dsinθ. For each element of interest the detector rotated and counted x-
ray photons produced for a set amount of time. These measurements done were compared to the
x-ray counts for a series of standards which were in turn used to convert x-ray fluxes to sample
composition.
Table 3. Electron Probe Operating Conditions Operating Condition Measurement
Accelerating Voltage 15 kV
Cup Current 20 nA
Beam Current 10 nA
Beam Diameter 2 µm
Standards were selected that had similar chemical compositions to the phases analyzed.
Raw x-ray counts were converted to composition by using the ZAF (Z: atomic number, A:
absorption, F: fluorescence) correction procedure. The relative uncertainty of the measurement
due to counting statistics can be calculated, and converted to absolute uncertainty by multiplying
the measured data by their respective relative uncertainty (1σ). The uncertainty measured in the
chemical formulas was calculated by applying the relative uncertainty calculated from each weight
percent oxide to the moles of element in the chemical formula of interest. The uncertainty of each
measurement was propagated using the methods of Harvard University Physical Science
Department (2007). The standards used for epidote are ones that contained similar elements such
as anorthite and hornblende (Table 4).
12
Table 4. Standards for Analysis of Mineral Phases by EPMA Element Plagioclase Epidote Chlorite
Na Plagioclase (Lake County) Plagioclase (Lake County) Hornblende-Engles
Mn Rhodonite (Broken Hill) Rhodonite (Broken Hill) Rhodonite (Broken Hill)
K Orthoclase (Ontario) Orthoclase (Ontario) Orthoclase (Ontario)
Ca Plagioclase (Lake County) Anorthite Titanite
Si Plagioclase(Lake County) Anorthite Hornblende-Engels
Mg Hornblende-Engels Hornblende-Engels Hornblende-Engels
Fe Hornblende-Engels Hornblende-Engels Hornblende-Engels
Ti Titanite Titanite Titanite
Al Plagioclase (Lake County) Anorthite Orthoclase
Statistical Tests for EPMA
Box and Whisker Plots: (1) Composition of Associates Plagioclase and (3) Depth
Box and whisker plots were used to graphically represent the data collected. The extrema
of whiskers indicate the maximum and minimum range of values measured. The horizontal line
bisecting the box is the median of measured values. The lower and upper portions of the box on
either side of the median represent the 25th to 50th percentile and the 50th to the 75th percentile
respectively. The lower extrema whisker to the bottom of the lower box and the top of the top box
to the higher extrema whisker indicate the bottom 0 to 25th percentile and the upper 75th to 100th
percentile.
Median Absolute Deviation (MAD)
Median Absolute Deviation (MAD) measures the absolute deviations from the median.
MAD is used for non-normally distributed data and is not directly influenced by outliers, the MAD
measures the absolute deviations from the median (Rousseeuw and Croux, 1993).
MAD = mediani (ǀXi – medianj(Xj)ǀ)
Where,
Xi are the values of each analysis
medianj(Xj) is the median of the data set
Simple Regression Analysis: (2) Proximity to Vein
Data were tested for each hypothesis by using regression and correlation analysis, standard
statistical tests, and appropriate error propagation. Assumptions that go into this model are the
following: the data will have a Gaussian distribution, errors in independent variables are greater
than errors in dependent variables, and that each sample is identically independent from other
samples.
Simple linear regression and correlation were used to test if there is a positive or negative
linear correlation with the composition of epidote and chlorite with respect to distance from veins.
The first-order linear model or simple linear regression model is the following:
13
y = β0x + β1 + ε
Where,
y is the dependent variable (distance)
x is the independent variable (composition)
β0 is the y-intercept
β1 is the slope of the line
ε is the error variable
The least squares line was derived by using measured data points on the electron probe and
is defined by the equation:
�̂� = b0 + b1x
Using the WDS composition (x) and coordinates (y) of epidote and chlorite from the
electron microprobe b0 and b1 were calculated:
b1 = 𝑠𝑥𝑦
𝑠𝑥2
b0 = �̅� - b1�̅�
Where,
𝑠𝑥𝑦 = ∑ (𝑥𝑖−�̅�)(𝑦𝑖−�̅�)𝑛
𝑖=1
𝑛−1
𝑠𝑥2=
∑ (𝑥𝑖−�̅�)2𝑛𝑖=1
𝑛−1
�̅� = ∑ 𝑥𝑖
𝑛𝑖=1
𝑛
�̅� = ∑ 𝑦𝑖
𝑛𝑖=1
𝑛
The standard error of the estimate and the sum of squares of error were calculated using
the following formulas:
SSE = ∑ (𝑦𝑖 − �̂�𝑖)2𝑛𝑖=1 = (n-1)(𝑠𝑦
2 − 𝑠𝑥𝑦
2
𝑠𝑥2 )
𝑠𝜀2=
𝑆𝑆𝐸
𝑛−2
The estimated standard error of b1 was calculated using the following equation:
𝑠𝑏1=
𝑠𝜀
√(𝑛−1)𝑠𝑥2
14
A t-test was conducted using to test the following hypotheses:
H0: β0 > 0
H1: β0 ≤ 0
t = 𝑏1− 𝛽1
𝑠𝑏1
A 10% significance level was used, the null hypothesis would be rejected for chlorite if
t <1.345 and epidote t < 1.310.
X-Ray Diffraction (XRD)
X-Ray Diffraction (XRD) analysis was done on samples 396 m, 888 m, 980 m, 1,044 m,
1,193 m, and 1,249 m to identify phases that could not be identified using optical microscopy or
EDS. Identifying all phases in the sample is essential to understanding the reactants and products
of geothermal reactions. Phases of interest that were thought to be present in small quantities were
the following: prehnite, magnetite, hematite, diopside, biotite and wairakite (Moore and others,
2008). XRD analysis was done by Frank Dulong at the USGS in Reston, Virgina. Each sample
was poured out on a clean piece of paper and was divided into equal slices, one slice of powder
weighing 3 grams was placed in a glass container to be analyzed. At the USGS, each powdered
sample was placed and packed into a sample holder. Due to the packing the sample, the minerals,
especially, the clay minerals would have a preferred orientation and the relative peaks recorded by
XRD would be of different intensities.
XRD works by accelerating a current through a tungsten filament to produce electrons that
are directed to a metal plate – commonly a copper source (as was the case for these analyses).
When the electrons strike the metal plate a characteristic x-ray is produced with a known
wavelength (CuKa = 0.15418 nm). The x-ray source is positioned on one side of the sample and a
Geiger counter is positioned on the opposite side. The x-ray source strikes the sample at a certain
angle (θ) and the Giger counter positioned across from it counts the x-rays in phase. The Bragg
equation is used to calculate the d-spacing using the 2θ angle and the corresponding x-ray
wavelength, nλ = 2dsinθ. Every 2θ value has a corresponding intensity (counts). The peaks of these
counts are used to determine the phases present in the sample. The American Mineralogist Crystal
Structure Database was used to decipher the peaks that correspond to each phase present in the
sample.
Statistical Tests for XRD
XRD was be used to obtain qualitative information on phases present in samples that were
not previously discerned using EDS. XRD detection limits are approximately less than 5% trace
amounts and Weighted R Profile and Goodness of Fit less than 10 and 1 respectively are considered
good analyses (F Dulong 2015, pers. comm., 3 November).
15
Thin Section Images
Scans of each thin section were made to aid in the mapping of the location of phases
identified during petrographic analysis and to aid in the documentation of EDS analyses. Pictures
of all the samples were taken with an optical microscope with a 1.5x magnification with a 10x
magnification eyepiece to further document textures within the samples. The pictures of the thin
section were aggregated to form a higher resolution image of the entire thin section. The high
resolution thin section images were used to locate grains of interest as well as document the
locations of analysis in each thin section. See Appendix B for scanned images of thin sections.
Image Analysis: Point Counting
Point counting was conducted on sample1,044 m using EDS. Point counting was done to
calculate the area (volume) percent of epidote in the thin section (26 mm X 46 mm). The method
from Hutchinson (1974) was closely followed to calculate the volume percent of epidote in both
thin sections. The central area of each thin section was selected (24 mm X 24 mm) and divided
into 21 X 41 cell units, for a total of 861 cells measuring 1 mm in length. The electron microprobe
was programed to move in 1 mm increments on a 21 X 41 grid. For each point and EDS spectra
was read and the phase was identified as one of the following: epidote, chlorite, plagioclase, pyrite,
other, or no rock. If there was a discrepancy in the EDS spectra, the BSE image was used to
determine if there were two phases detected. In cases where the EDS detected more than one phase,
a rule was predetermined that the phase directly to the left or above the determined point was
recorded.
From the point counting data the percent of each phase was calculated using the following
formula:
P = (𝑝
𝑛∗ 100)
Where,
P: percent of phase present by area (volume)
p: points counted of that phase
n: total amount of points counted (not including no rock)
The uncertainty associated with point counting were calculated using Van Der Plas and
Tobi (1965) formula:
σ =√𝑝(100−𝑃)
𝑛
Where,
P: percent of phase present by area (volume)
p: points counted of that phase
n: total amount of points counted (not including no rock)
16
Van Der Plas and Tobi’s (1965) uncertainty estimates were cross referenced with Howarth
(1998) 95 percent confidence figure to verify the range of uncertainties associated with each phase
measured.
The Plagioclase and Magnetite Mode, or “Plag+Mag Model” is a mathematical model used
to calculate the amount of ferric iron in the original rock to estimate the volume percent of epidote
production. This model assumes epidote is the only ferric iron-bearing mineral produced and that
the total amount of ferric iron in the original rock and altered rock is the same.
Plagioclase and Magnetite Model: “Plag+Mag Model”
A model was developed, the “Plag+Mag Model” to aid in the calculation of the total
amount of ferric iron in the original Galunggung Formation basalts. This was done using Bronto’s
(1989) data on modal proportions of minerals and the composition of each mineral. This model
assumes that the only phases containing Fe3+ are magnetite and plagioclase. According to Bronto
(1989), the ratio Fe3+/Fe2+ is 0.3 in magnetite, and further, he reports iron as FeO wt% of 0.50,
0.66, and 0.47 (Fe2O3 wt% of 0.56, 0.73, and 0.52) in plagioclase in the Cibanjaran, Tasikmalaya,
and Old Galunggung Formations, respectively. In future work, the Fe3+/Fe2+ in glass and other
phases can be included. Bronto’s modal proportions of magnetite and plagioclase were used to
calculate a model concentration of Fe3+ in the unaltered rock; this “Plag+Mt Model” assumes that
whole rock ratio of Fe3+/Fe2+ is controlled primarily by plagioclase, the dominant phase in the
rock, and magnetite, the phase with highest Fe3+/Fe2+. The stoichiometric amount of epidote was
calculated using the highest and median Fe/(Fe+Al) ratios in epidote determined by EPMA in the
altered rocks. During high-temperature hydrothermal alteration at the appropriate oxygen fugacity,
minerals such as epidote will accommodate Fe3+ as an essential structural constituent. Holding all
other variables constant, if the Karaha Telaga Bodas geothermal system had originally high-
temperature oxidizing fluids the Fe2+ in the rock would have oxidized and the Fe3+ content in
epidote would have increased as a result.
(1) Potential relationship between the chemical composition of plagioclase and epidote
Optical microscopy was preformed to identify plagioclase, epidote, chlorite, actinolite and
other phases in thin section. A minimum of one plagioclase crystal was analyzed with Wavelength
Dispersive Spectroscopy (WDS) from edge to edge in each sample. Due to the alteration in the
samples, a straight traverse across the grain was not always be feasible. Therefore, the path was
adjusted to accommodate (i.e. avoide) the alteration. A potential limitation of this approach is
orientation of the crystal in thin section. The cut of the plagioclase crystal may not be through the
center of the crystal. The orientation of the crystal in the thin section could yield data that is not
necessarily a representative range of the entire range of mole fraction anorthite. For example,
measuring a thin slice of the edge of a plagioclase crystal may produce very similar albite-rich
data.
Additionally, several other plagioclase crystal cores were analyzed. Cores have undergone
less hydrothermal alteration than the rims. WDS analysis was done on epidote grains that were not
adjacent to veins, two measurements were taken for each grain identified. Elongate epidote crystals
were identified and a traverse along the c axis and perpendicular to the c axis was identified and
17
points along the grain were measured using WDS to evaluate if there was chemical zoning in the
crystal.
(2) Proximity to veins
Analysis of hand samples and optical microscopy was performed to identify veins in the
sample. Billets from the thin section making process were used to determine the angle at which
the veins intersect the thin section surface. Veins that intersect the thin section at angles less than
45⁰ were excluded from the analysis. The coordinate system in the microprobe analyzer was used
to determine the lines that define the vein in X-Y space. EDS was used to confirm the presence of
epidote and then WDS was used to measure the composition of epidote grains. Two measurements
were taken for each grain and the coordinates of the grain were be catalogued in order to measure
the absolute distance from the measured epidote grain to the line that defines the vein. The
chemical composition of the epidote grains were measured and compared to the distance from the
vein. This same procedure was done with chlorite grains to determine whether there is a
relationship between the composition of the epidote and chlorite with respect to each minerals
distance from the vein. This analysis was done for one vein in the T-2 core.
(3) Depth
Data from the epidote grains analyzed in “(1) Chemical composition of plagioclase with
respect to epidote” were compared to the depth of the sample from the drill core. For the purpose
of this study, the given depths are considered to be true values. Chemical composition of chlorite
was measured from each sample and was compared with the depth of the sample from the drill
core. Each chlorite grain was analyzed twice.
(4) Original Rock Composition
Point counting was used to calculate the volume percent of epidote in the altered rocks
(sample 1,044 m). The “Plag+Mag Model” was used to estimate the total amount of epidote
production from alteration if all of the ferric iron in the original rock were used in epidote
production. The measured composition of epidote from WDS was used to constrain the volume of
epidote production. Two theoretical endmembers of altered rocks will be used to test whether the
assumptions of the proportion of total epidote production are reasonable.
18
VI. PRESENTATION OF DATA AND DISCUSSION OF RESULTS
Data from EPMA
EDS was performed on eight samples from the following depths: 396 m, 888 m 961 m, 980
m, 1,044 m, 1,193 m, 1,249 m and 1,378 m. Epidote and chlorite were found in all samples except
1,249 m and 1,378 m. Amphibole was identified in the two deepest samples 1,249 m and 1,378 m.
Plagioclase was identified in all eight samples (see Table 2 and Appendix C) and WDS analysis
was performed on plagioclase from samples 396 m, 888 m, 961 m, 980 m, 1,249 m, and 1,378 m,
see Appendix D.
Data from WDS was processed and was scrutinized according to the parameters in Table 5.
Table 5. Parameters used to discriminate data Phase Total Weight Percent Additional Reasoning for
Omitting Analysis
Plagioclase 98%-102% Moles of Na+Ca ≠ 1 (when
rounded to 1 significant figure on
the basis of 8 oxygen)
Epidote 97.5% - 101% Moles of Al+Fe ≠ 3 (when rounded
to 1 significant figure on the basis
of 12 oxygen)
Chlorite 85-92% K2O >1.5 wt. %
(1) Chemical composition of plagioclase with respect to epidote
Plagioclase cores from samples 396 m, 888 m, 961 m, 980 m, 1,249 m, and 1,378 m and
epidote grains from samples 396 m, 888 m, 961 m, and 980 m were analyzed by EPMA. The
median mole fraction anorthite from samples 396 m, 888 m, 961 m, 980 m, 1,249 m, and 1,378 m
are XAn = 0.72, 0.82, 0.88, 0.91, 0.94, and 0.59. The mole anorthite in the plagioclase increased
with depth, with the exception of the sample 1,378 m. A possible explanation for the different
plagioclase compositions could be the depths at which the grains are found. Plagioclase found at
greater depths may be more calcic due to a different magma composition. The rims of the
plagioclase grains may be more sodic due to hydrothermal alteration. Hydrothermal fluids alter
the plagioclase rim and make it more sodium-rich. Alternatively, the increase in mole fraction
anorthite could suggest decreasing hydrothermal alteration with depth, this statement takes into
the consideration the assumption that the original rock at all depths had plagioclase of the same
composition.
The mole fraction anorthite of sample 1,249 m, XAn = 0.59 is the lowest median value of
all samples. Possible explanations for this low value is that this sample could be representative of
a different magma composition, such as dike or a sill, or that this sample was exposed to a higher
water/rock ratio.
The median mole fraction pistacite in epidote in samples 396 m, 888 m, 961 m, 980 m,
1,249 m, and 1,378 m are XPs = 0.23, 0.21, 0.26, and 0.23. There is variation in the composition
of epidote in each grain, which fits with Bird and Spieler (2004) observations of micron scale
oscillatory zoning in epidote. There is no apparent increase or decrease in XPs in epidote that
corresponds with the XAn in plagioclase. The composition of plagioclase does not appear to
influence the composition of epidote in this system. The abundance of plagioclase may contribute
to the abundance of epidote; this hypothesis could be tested in future studies.
19
Table 6. MAD Values for plagioclase
Sample 396 m 888 m 961 m 980 m 1,249 m 1,378 m
MAD (XAn) 0.079 0.022 0.019 0.046 0.015 0.028
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
396 888 961 980 1,249 1,378
Mole
Fra
ctio
n A
n
Depth (m)
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
396 888 961 980
Xp
s
Depth (m)
Figure 7. Mole fraction of pistacite with respect to depth (m) of sample. 37 measurements were taken for
sample 396 m, 26 measurements for sample 888 m, 48 measurements for sample 961 m, and 32
measurements for sample 980 m.
Figure 6. Chemical composition of plagioclase cores in terms of mole fraction of anorthite with respect
to depth (m) of sample. 50 measurements were taken for sample 396 m, 16 measurements for sample 888
m, 7 measurements for sample 961 m, 76 measurements for sample 980 m, 71 measurements for sample
1,249 m, and 22 measurements for sample 1,378 m.
20
Table 7. MAD Values for epidote
(2) Proximity to veins
One vein intersecting at an angle greater than 45⁰ relative to the cut of the thin section was
identified in sample 961 m. Two WDS measurements were taken in each epidote and chlorite grain
and their corresponding coordinates were documented. The Xps of epidote does not appear to have
a trend with respect to the distance from the vein. Measurements were taken from 0.4 mm to 3.10
mm from the vein and may not have been sufficiently far away to observe a positive or negative
correlation.
The mole fraction of Fe/Mg and Fe/Al in chlorite are between 0.73 and 1.23 and 0.8 to
1.11, respectively. This further indicates the possibility that the water to rock ratio does not
influence the composition of epidote or chlorite or that the measurements were not taken far
enough away from the vein. The ratio of Fe/Mg and Fe/Al in chlorite and the Xps do not appear to
indicate significant compositional change in either phase, see Appendix E for linear regression
statistical tests. In future studies, this relationship should be looked at more closely and fluid
inclusions should be used to determine the fluid composition that was interacting with the rock.
(3) Depth
Analyses suggests that chemical composition of epidote does not vary with depth. The
median mole fraction pistacite in epidote in samples 396 m, 888 m, 961 m, 980 m, 1,249 m, and
1,378 m are XPs = 0.23, 0.21, 0.26, and 0.23. The median Fe/Mg ratios in chlorite for samples 396
m, 888 m, 961 m, 980 m are 0.63, 1.34, 0.93, and 0.78. The median Fe/Al ratios for samples 396
m, 888 m, 961 m, 980 m are 0.75, 0.88, 0.99, and 0.85. There is no apparent trend in the ratio of
Sample 396 m 888 m 961 m 980 m
MAD [Fe/(Fe+Al)] 0.021 0.023 0.031 0.048
Figure 8. Molar ratio of Fe/Al in pistacite with respect to distance from vein (mm). The uncertainty is
contained within the points. Each epidote grained was analyzed twice, a total of 32 measurements were
taken for epidote and each chlorite grain was analyzed twice, a total of 14 measurements were taken.
y = -0.0112x + 0.3825
R² = 0.012
y = -0.066 + 1.055
R² = 0.0137
0.0
0.2
0.4
0.6
0.8
1.0
1.2
0 0.5 1 1.5 2 2.5 3 3.5
Mola
r F
e/A
l
Distance from vein (mm)
21
Fe/Mg and Fe/Al in chlorite with respect to depth. Notably, in sample 396 m there is spread is
narrow, compared to samples 888 m, 961 m, and 980 m.
The difference in Fe/Mg and Fe/Al in chlorite may be caused by different original bulk
rock composition. However, if both samples have the same original bulk rock composition, fluids
and permeability are likely the factors controlling the chemical composition. More importantly,
within the same thin section there is a wide variety of composition for epidote and chlorite; this
suggests disequilibrium between phases on a micron scale. The fluid appears to be the driving
factor in the variation of composition in epidote and chlorite. Compositions and textures will be
compared with oxidation and reduction assemblages in order to identify areas of high and low
permeability.
Table 8. MAD Values for epidote
Sample 396 m 888 m 961 m 980 m
MAD [Fe/(Fe+Al)] 0.021 0.023 0.031 0.048
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
396 888 961 980
Xp
s
Depth (m)
Figure 9. Mole fraction of pistacite with respect to depth (m) of sample. 37 measurements were taken
for sample 396 m, 26 measurements for sample 888 m, 48 measurements for sample 961 m, and 32
measurements for sample 980 m.
22
Table 9. MAD Values for molar ratio of Fe/Mg in chlorite
Sample 396 m 888 m 961 m 980 m
MAD (Fe/Mg) 0.025 0.065 0.153 0.059
Table 10. MAD Values for molar ratio of Fe/Al in chlorite
Sample 396 m 888 m 961 m 980 m
MAD (Fe/Al) 0.017 0.095 0.065 0.047
0
0.5
1
1.5
2
2.5
396 888 961 980
Mola
r F
e/M
g
Depth (m)
0
0.2
0.4
0.6
0.8
1
1.2
396 888 961 980
Mola
r F
e/A
l
Depth (m)
Figure 10. Molar ratio of Fe/Mg in chlorite with respect to with respect to depth. 10 measurements were
taken for sample 396 m, 13 measurements for sample 888 m, 14 measurements were taken for 961 m,
and 20 measurements for 980 m.
Figure 11. Molar ratio of Fe/Al in chlorite with respect to depth. 10 measurements were taken for sample
396 m, 13 measurements for sample 888 m, 14 measurements were taken for 961 m, and 20 measurements
for 980 m.
23
There appears to be no direct relationship between the Xps with the composition of
associated plagioclase, distance from veins, or depth. However, new insights were made based on
the data collected. Based on the data collected, the plagioclase composition may not influence
epidote composition, but the abundance of epidote may be correlated to the abundance of
plagioclase. Likewise, the epidote and chlorite compositions do not appear to be correlated with
distance from the vein, possibly the distance was not sufficient to identify a positive or negative
correlation. Lastly, the epidote composition does not appear to change with respect to depth,
however, the Fe/Al and Fe/Mg ratios of chlorite did. Further work is required to understand the
variables and chemical reactions in the geothermal system that may be influencing variations in
phase composition in these preliminary results.
Composition of Epidote, Chlorite, and Amphibole in T-2
The composition of epidote and chlorite are not uniform in each sample. The range of
compositions of chlorite in the shallowest 396 m sample have the largest variation in composition
and are the most enriched in aluminum. Similar to previous graphical representations, the
composition of epidote varies consistently throughout the core. The composition epidote in sample
396 m is comparable to the composition of epidote in the other three samples, however, the
composition of chlorite at 396 m could be recording a different stage in the alteration process
(assuming the same protolith).
The amphibole compositions in sample 1,249 m range from actinolite to hornblende. The
measured composition of amphiboles in sample 1,378 m are hornblende.
Al
MgFe
Al
Mg/FeCa
Figure 12. Ternary diagram containing epidote (circles)
and chlorite (square) compositions. Green, blue, yellow,
and red correspond to depths of 396 m, 888 m, 961 m,
and 980 m respectively.
Figure 13. Ternary diagram containing amphibole
(circle) compositions. Black and orange correspond to
depths of 1,249 m and 1,378 m respectively. Fe2+ and
Fe3+ are collapsed on one another in this diagram.
24
X-Ray Diffraction Spectroscopy
Table 11. Phases detected by using XRD Sample Pl Qtz Chl Ilt Ep Ilm Ttn Py Ap Wrk Cal Rt Ccp Amp Bt Afs
396 m x x x x x* x* x* x* x*
888 m x x x x* x x* x x* x* x*
980 m x x x x* x* x* x
1,044 m x x x x x* x* x x* x*
1,193 m x x x* x* x* x* x x
1,249 m x x x* x* x* x* x x*
Table 12. Weighted R Profile and Goodness of Fit for XRD Sample Weighted R Profile Goodness of Fit
396 m 10.9 2.29
888 m 9.9 2.06
980 m 14.2 3.27
1,044 m 10.6 2.31
1,193 m 11.0 2.72
1,249 m 9.3 2.14
X-Ray Diffraction (XRD) was done on six samples on 396 m, 888 m, 980 m, 1,044 m,
1,193 m, and 1,249 m using an x-ray with a Cu Kα wavelength. The XRD spectra without Rietveld
analysis detected major phases in each sample, see Table 11. Once Rietveld quantitative phase
analysis was done using phases identified previously via Energy Dispersive Spectroscopy (EDS)
additional minor phases were identified in the XRD spectra. The mineral epidote was identified in
the first five samples in minor concentrations, epidote was not detected in the deepest sample.
Wairakite was detected as a major phase in sample 888 m, wairakite was not previously identified
using EDS or optical microscopy. The mineral illite was detected as a major phase in samples 396
m, 888 m, and 1,044 m and was not previously identified through EDS. The mineral prehnite was
not detected using XRD, nor was it detected by using EDS. According to Frank Dulong, robust
results should have a Weighted R Profile should the Goodness of Fit values below 10 and 1,
respectively (F Dulong 2015, pers. comm., 3 November). All samples except 888 m and 1,249 m
have a Weighted R Profile that exceed 10 and all of the samples have a Goodness of Fit that
exceeds 1. The XRD analysis done on the six samples serve to identify phases, however, additional
information such as volume percent do not appear to be reliable. See Appendix F for
diffractograms.
Pl = plagioclase; Qtz = quartz; Chl = chlorite; Ilt = illite; Ep = epidote; Ilm = Ilmenite; Ttn = titanite; Py = pyrite;
Ap = apatite; Wrk = wairakite; Cal = calcite; Rt = rutile; Ccp = chalcopyrite; Amp= amphibole; Bt = biotite; Afs =
alkali-feldspar. X-Ray Diffraction and *Rietveld analysis was used to identify phases.
25
“Plag + Mag Model” Calculation
Bronto (1989) reports the modal abundance of phenocrysts and groundmass in basalts and
basaltic-andesites. The dominant phases that contain ferric iron in these samples are plagioclase
and magnetite (Lundgaard and Tegner, 2004). A back-of-the-envelope calculation was done using
the proportion of phenocrysts as a proxy of the mineral proportion in the groundmass, this
calculation estimated volume percent of magnetite of 0.37 volume percent and 1.91 weight
percent, however, when the plagioclase abundance was calculated in the same way the volume
percent of plagioclase was 85.13, which exceeds 100 weight percent of the rock, this is not
possible. To estimate a more accurate weight percent of plagioclase a normative mineralogy was
calculated using the median bulk rock composition of the Old Galunggung whole rock analyses
done via XRF by Bronto (1989) using Kurt Hollocher’s CIPW Excel program. Bronto reported
the bulk rock composition as Fe2O3, however, when the CIPW phases are calculated using Fe2O3,
hematite is present in the original rock – Bronto (1989) does not report hematite in the original
rock. Therefore, the Fe3O2 weight percent will be converted to FeO for the purpose of calculating
the weight percent plagioclase using the CIPW.
Fe2O3 in the Whole Rock from Magnetite and Plagioclase
By using the median value of Bronto’s (1989) measurements of modal abundance (as
volume proportion) of magnetite phenocrysts and assuming the same proportion of magnetite
phenocrysts to total phenocrysts in the groundmass, an estimate of volume percent of magnetite in
the basalt was calculated in Table 13.
Figure 14. XRD diffractogram of sample 888 m.
26
Table 13. Volume % of phenocrysts and groundmass in Old Galunggung Formation Sample Median
vol.%
Norm
vol. %
Total
vol. %
pheno-
crysts
Prop. of
pheno-
crysts
Vol. %
in GM
from
prop.
Total
vol. %
Avg.
specific
gravity
(gm/cc)
Wt % Norm.
wt%
OL 1.10 1.09 26.83 0.04 2.97 4.06 3.32 13.49 4.77
OP 0.65 0.64 26.83 0.02 1.76 2.40 3.50 8.40 2.97
CP 2.20 2.18 26.83 0.08 5.95 8.13 3.60 29.25 10.34
MA 0.10 0.10 26.83 0.00 0.27 0.37 5.15 1.90 0.67
PL 23.05 22.82 26.83 0.85 62.31 85.13 2.70 229.85 81.25
GM 74.00 73.26
Total 101.10 282.90 100.00
Normalization Factor for “Median vol % abundance” = 0.99 and “wt %” = 0.35.
Fe2O3 from Magnetite
Data from Bronto’s (1989) thesis on the chemical composition of magnetite was used to
derive an approximate chemical formula for magnetite from the Old Galunggung Formation. The
moles of element per 32 oxygen were normalized to moles of element per 4 oxygen. The most
abundant single valence elements, Ti, Al, and Mg were used to calculate the total amount of Fe2+
corresponding to spinel with compositions of Mg2TiO4 and Fe2+Al2O4. The sum of moles of
elements (Ti, Al, Mg, Fe2+) calculated from the abundance of Ti, Al, and Mg was 0.78. The
remaining cations in the magnetite, 2.22, were assumed to be iron, Fe2+Fe23+O4. The ratio of,
Fe2+/Fe3+ in magnetite is 0.5 and the sum of Fe2+ + Fe3+ = 2.22, using substitution the amount of
Fe2+ and Fe3+ can be calculated and is 1.34 and 0.89 respectively. See Table 14 for Old Galunggung
magnetite composition.
Table 14. Composition of Old Galunggung Formation magnetite normalized to 32 oxygen Oxide Wt %
oxide
Moles of element
per 32 Oxygen
Moles of element
per 4 Oxygen
SiO2 0.106 0.036 0.005
Al2O3 3.841 1.523 0.190
TiO2 14.606 3.697 0.462
FeO* 74.992 21.107 2.638
MnO 0.378 0.108 0.014
MgO 1.955 0.981 0.123
CaO 0.001 0.000
Na2O 0.000
K2O 0.009 0.004 0.001
NiO 0.000
Cr2O3 0.131 0.035 0.004
Total 96.019 27.491 3.436
FeO* all iron was calculated as ferrous iron.
The normalized weight percent of magnetite is 0.67 wt %. According to Bronto (1989) the
composition of magnetite is approximately:
Fe2+1.34Mg0.12Fe3+
0.89Ti0.46Al0.19O4
27
1.34(71.84 g/mol) + 0.12(40.30 g/mol) + 0.89(159.69 g/mol) + 0.46(79.87 g/mol) + 0.19(101.96
g/mol) = 299.34 g/mol
Proportion of Fe2O3 g/mol in magnetite per Fe2+1.34Mg0.12Fe3+
0.89Ti0.46Al0.19O4 magnetite:
[(0.89)(159.69 g/mol)]/299.35 g/mol = 0.475
Weight percent of magnetite due to Fe2O3:
(0.67 wt % Fe2O3 in magnetite)(0.475) = 0.319 wt% of Fe2O3 (0.287 wt% FeO) due to magnetite
Fe2O3 from Plagioclase
Using Table 13, the normalized 81.25 % weight percent of plagioclase using phenocryst
proportions is too high for a basalt. CIPW normative analysis was done to calculate a normative
weight percent for plagioclase using the median whole rock analyses of the Old Galunggung
Formation and normalizing the values, see Table 15.
Table 15. Composition of representative Galunggung volcanic rocks Major Elements
(wt %)
20258 20270 L27-7 20288 Median Normalized
wt %
SiO2 47.06 49.67 52.33 56.99 51.00 51.39
TiO2 0.87 1.03 0.94 0.84 0.91 0.91
Al2O3 15.67 20.74 19.51 18.96 19.24 19.38
Fe2O3* 9.45 9.62 8.79 7.66 9.12 9.19
MnO 0.26 0.19 0.17 0.12 0.18 0.18
MgO 10.32 4.38 4.82 3.21 4.60 4.63
CaO 11.26 10.85 9.59 7.66 10.22 10.30
Na2O 1.46 2.99 3.29 4.29 3.14 3.16
K2O 0.56 0.37 0.56 0.71 0.56 0.56
P2O5 0.11 0.13 0.18 0.19 0.16 0.16
LOI 1.54 0.52 -0.25 -0.44 0.14 0.14
Total 98.56 100.49 99.93 100.08 99.25 100.00
Normalization Factor = 1.008
* all iron in rock was calculated as Fe2O3.
Fe2O3 = 9.19 wt % or FeO = 8.21 wt %
Table 16. CIPW normative mineralogy of using median composition of plagioclase from the Old
Galunggung Formation from Table 15 Mineral Weight Percent
Plagioclase 64.36
Orthoclase 3.37
Diopside 10.20
Hypersthene 16.56
Olivine 3.08
Ilmenite 1.75
Apatite 0.32
Total 100.01
FeO wt % was used for calculation.
28
CIPW weight percent plagioclase is 64.36%. Bronto (1989) reports the average
composition of plagioclase in the Galunggung Formation. The XAn of plagioclase cores and rims
in the unaltered Old Galunggung Formation samples range from 0.95 to 0.80 and 0.80 to 0.50,
respectively. See Table 17 for the average composition of plagioclase in the Old Galunggung
Formation according to Bronto.
Table 17. Average composition of plagioclase in Old Galunggung Formation Oxide Weight Percent
SiO2 44.35
Al2O3 35.42
TiO2 0.00
FeO 0.47
MnO 0.06
MgO 0.08
CaO 18.83
Na2O 0.66
K2O 0.02
NiO 0.02
Cr2O3 0.00
Cl- 0.00
Total 99.96
All iron in plagioclase was calculated as FeO.
FeO = 0.47 wt % Fe2O3 = 0.52 wt %.
The FeO in plagioclase can be converted to Fe2O3 because Lundgaard and Tegner (2004)
suggest that the partition coefficients of Fe2O3 can range from 16 to 20 times that of FeO in
plagioclase.
Proportion of Fe2O3 in plagioclase:
(0.52 wt % Fe2O3)/(99.96 total wt %) = 0.0052
Weight percent of plagioclase due to Fe2O3:
(64.38 wt %)(0.0052) = 0.335 wt % of Fe2O3 (0.301 wt % FeO) due to plagioclase
Total wt % of Fe2O3 in Rock Due to Magnetite and Plagioclase
0.319 wt % + 0.335 wt % = 0.654 wt % Fe2O3 (0.589 wt % FeO) in rock from magnetite and
plagioclase
Assumption: all ferric iron is from magnetite and plagioclase
FeO in original rock = 8.21 wt % FeO – 0.589 wt% FeO = 7.617 wt % FeO
Fe2O3 in original rock = 0.654 wt % Fe2O3
29
Epidote Production
Assumption: all the ferric iron in the original rock produces epidote: no other alteration
minerals are produced. The highest and median mole fraction pistacite values measured in epidote
from drill core T-2 will be used to calculate the range of epidote production possible if all the ferric
iron in magnetite and plagioclase was used to produce epidote as an alteration mineral.
Table 18. Maximum and median Fe2O3 wt% in epidote Maximum Median
Ps 0.367 0.232
Fe3+ 1.108 0.752
Al3+ 1.909 2.251
Chemical Formula Ca2Fe1.108Al1.909Si3O12(OH) Ca2Fe0.752Al2.251Si3O12(OH)
Wt % from Fe2O3 35.28 wt % Fe2O3 33.54 wt % Fe2O3
Wt % of Fe2O3 in epidote (0.367)(35.28 wt % Fe2O3) = 12.95 wt % (0.232)(33.54 wt % Fe2O3) = 7.78 wt %
Assumption: all magnetite and plagioclase are altered to produce epidote.
Production of epidote with maximum iron composition:
(0.654 wt % Fe2O3 in rock)/(12.95 wt % Fe2O3 in epidote) = 5.05 vol % of rock that is epidote
Production of epidote with median composition:
(0.654 wt % Fe2O3 in rock)/(7.78 wt % Fe2O3 in epidote) = 8.41 vol % of rock that is epidote
Assumption: only magnetite is altered to produce epidote.
Production of epidote with maximum iron composition:
(0.319 wt % Fe2O3 in magnetite)/(12.95 wt % Fe2O3 in epidote) = 2.47 vol % of rock that is epidote
Production of epidote with median composition:
(0.319 wt % Fe2O3 in magnetite)/(7.78 wt % Fe2O3 in epidote) = 4.10 vol % of rock that is epidote
Theoretical Models of Altered Rocks to Calculate Volume % of Epidote
Using the most abundant phases in the altered rocks.
Table 19. Theoretical model with high volume % epidote Phase Wt % Avg. density Vol.% Vol. % normalized
Plagioclase 5 2.73 1.83 6.96
Albite 5 2.6 1.92 7.31
Quartz 12 2.65 4.72 17.22
Chlorite 10 3 3.33 12.67
Illite 5 2.77 1.81 6.86
Pyrite 60 5 12.00 45.63
Epidote 3 3.41 0.73 3.34
Total 100 26.34 100.00
Normalization Factor = 3.80
30
Table 20. Theoretical model with low volume % epidote Phase Wt % Avg. density Vol.% Vol. % normalized
Plagioclase 30 2.73 18.32 30.85
Albite 30 2.6 7.69 32.39
Quartz 13 2.65 6.60 13.77
Chlorite 14 3 1.67 13.10
Illite 4 2.77 1.44 4.05
Pyrite 6 5 0.20 3.37
Epidote 3 3.41 0.73 2.47
Total 100 36.65 100.00
Normalization Factor = 2.81
Range of vol. % of epidote in theoretical models of altered rocks range from 2.47% to
3.34%, which fall between the maximum and median values of epidote produced solely from the
alteration of magnetite.
Image Analysis Using EDS
Image analysis was done by using EDS on sample 1,044 m. Sample 1,044 m was placed in
the electron microprobe and an X-Y coordinate plane was used to space out a 21 X 41 grid with 1
mm apart spacing. A total of 861 points were measured by using EDS and the following
determinations were made: epidote, chlorite, pyrite, plagioclase, other, no rock, see Table 21. From
the 861 points counted, only 835 were rock.
Table 21. Summary of point count analysis Plagioclase Chlorite Epidote Pyrite Other Total
Data
Points
544 84 44 39 124 835
Percent 65.15% 10.06% 5.27% 4.67% 14.85% 100.00%
Error Associated with Point Count Analysis
According to Van Der Plas and Tobi (1965) the standard deviation in a point count analysis
can be described by the following equation:
σ =√𝑝(100−𝑃)
𝑛
where, p = the real content of a mineral in percent by volume
n = total number of points counted
P = percent of mineral
2σ was calculated for all phases identified using image analysis, the 2σ ranges computed
describe 95% of the measured proportions (percent) of each phase.
Epidote
31
Van Der Plas and Tobi (1965) 95% absolute uncertainty:
n = 835, p = 44, P = 5.27%
σ = 2.23% and 2σ = 4.47%
2σ range [3.04% to 7.5%]
Howarth (1998) 95% absolute uncertainty:
2σ range [3.87% to 6.67%]
Plagioclase:
Van Der Plas and Tobi (1965) 95% absolute uncertainty:
n = 835, p = 544, P = 65.15%
σ = 4.76% and 2σ = 9.53%
2σ range [60.39% to 69.91%]
Howarth (1998) 95% absolute uncertainty:
2σ range [61.75% to 68.55%]
Chlorite:
Van Der Plas and Tobi (1965) 95% absolute uncertainty:
n = 835, p = 84, P = 10.06%
σ = 2.98% and 2σ = 5.95%
2σ range [7.08% to 13.04%]
Howarth (1998) 95% absolute uncertainty:
2σ range [8.06% to 12.06%]
Pyrite:
Van Der Plas and Tobi (1965) 95% absolute uncertainty:
n = 835, p = 39, P = 4.67%
σ = 2.11% and 2σ = 4.22%
2σ range [2.56% to 6.78%]
Howarth (1998) 95% absolute uncertainty:
2σ range [3.37% to 5.97%]
Other:
Van Der Plas and Tobi (1965) 95% absolute uncertainty:
n = 835, p = 124, P = 14.85 %
σ = 3.56% and σ = 7.12%
2σ range [11.29% to 18.41%]
32
Howarth (1998) 95% absolute uncertainty:
2σ range [12.65% to 17.05%]
33
VIII. SUMMARY AND CONCLUSION
The characterization of epidote and associated mineral assemblages is crucial in
understanding the chemical reactions that produce or influence variations in composition. This
study measures potential variables that can influence the composition of epidote (Xps) and
concludes that in the Karaha-Telaga Bodas geothermal system the composition of epidote is not
positively or negatively correlated to: (1) mole fraction anorthite in associated plagioclase, (2)
distance from veins, or (3) depth. However, (4) the original bulk rock composition does influence
the composition minerals and the composition of alteration minerals during a hydrothermal
alteration.
The median mole fraction anorthite increases from 0.72 to 0.94 from 396 m to 1,249 m,
respectively, while the composition of epidote consistently ranges from median values, Xps, of
0.21 to 0.26 with no positive or negative linear trend. The deepest sample, 1,378 had the lowest
median mole anorthite value of 0.59, the lowest of all samples analyzed. This low value may be
explained by a different volcanic flow composition or could be caused by changing water content
in the system.
The composition of chlorite and epidote do not show demonstrate a statistically significant
correlation with distance from vein. A positive or negative trendline slope (b1) would correspond
to reducing or oxidizing fluids, respectively. In the future, further analysis should be done on
epidote and chlorite compositions and their respective distance form veins to determine if chemical
variation in epidote and chlorite exists on a larger, centimeter or meter scale.
The data from this study suggests that there is compositional variation at the micron scale
in epidote grains and that the composition of epidote does not appear to be influenced by depth, as
first hypothesized. The Xps in epidote ranges subtly between 0.21 and 0.26 with depth, however,
in chlorite the molar ratios of Fe/Mg and Fe/Al vary in an unsystematic fashion, indicating
disequilibrium between epidote and chlorite in each sample.
The XRD analysis provided information about the presence of major phase wairakite in
sample 888 m, and illite in samples 396 m, 888 m, and 1,044 m. The XRD analysis did not identify
prehnite, a mineral that if present could indicate cooling of the geothermal system (Moore, 2008).
Possibly suggesting that the fluids interacting with the samples analyzed have not begun to cool.
By using Bronto’s (1989) measurements of the original bulk rock composition of the Old
Gaulunggung Formation (Table 1) the mathematical “Plag+Mag Model” provides a range of
values from 2.47% to 4.10% and 5.05% to 8.41% for only magnetite alteration and magnetite and
plagioclase alteration, respectively. Point counting analysis was done to cross reference the
hypothetical volume percent range of epidote to the volume of epidote in sample 1,044 m. The
measured area (volume percent) calculated for sample 1,044 m was 5.27% with a 95% confidence
interval of [3.87% to 6.67%] (Howarth, 1998). The volume percent measured using image analysis
coincides with the “Plag+Mag Model” hypothetical values. The image analysis value is on the
cusp between complete magnetite alteration and magnetite and plagioclase alteration. If all the
magnetite was altered and a fraction of plagioclase was altered, the volume percent epidote in
sample 1,044 m could easily be explained by the “Plag+Mag Model.” The “Plag+Mag Model”
used in this study operates under the assumption that the fluids in the system are not oxidizing or
reducing. However, if the fluids were reducing or oxidizing the 95% confidence interval may be
too large to discern the difference between a non-oxidizing, non-reducing, oxidizing, or reducing
fluid conditions in the system.
34
From the statements of equilibrium described in the introduction, under non-oxidizing or
non-reducing conditions the hydrothermal alteration of basalt containing magnetite, iron-bearing
olivine, pyroxenes, clinopyroxenes, plagioclase and calcium-rich plagioclase can produce the
alteration minerals epidote and chlorite. In order to better constrain whether fluids are oxidizing
or reducing the ratio of Fe3+/Fe2+ in the original and altered rocks must be measured using ferrous
iron titration.
In addition to basalt alteration, statements of equilibrium with the sub-assemblage of
rutile+titanite+quartz can be viewed as a CaO buffer, consuming or supplying calcium in the
system which in turn limits the production of epidote. In samples 888 m, 980 m, 1,044 m
rutile+titante+quartz are all present along with epidote and chlorite which is consistent with
equilibrium conditions.
Ca2Fe3Si3O12(OH) + SiO2 + 3
2H2O + 2TiO2 = 2CaTiSiO5 +
3
4O2 +
1
2Fe6Si4O10(OH)8
(Ep ) (Qz) (Rt) (Ttn) (Fe-chl endmember)
35
VIII. BROADER IMPACTS AND SUGGESTIONS OF FUTURE WORK
This study provides a method of using chemical composition of the original bulk rock and
composition of alteration mineralogy, like Xps in epidote, to develop a model to estimate the
volume percent production of alteration mineralogy in order to compare the hypothetical volume
percent to a volume percent calculated using image analysis. Future studies should consider the
ferric iron in chlorite in addition to epidote and measure the volume percent of epidote and chlorite
in altered samples.
Additional work is required to physically measure the total amount of ferrous iron in the
original bulk rock and altered rock via ferrous iron titration in order to calculate the total amount
of ferric iron in the Old Galunggung Formation samples and altered samples. Physically measuring
the ferric iron in the Old Galunggung Formation samples and altered rock would test whether the
assumptions made in the “Plag+Mag Model” are reasonable.
Changes in ratio of Fe3+/Fe2+ from unaltered to altered rock and the distribution of iron in
iron-bearing alteration mineral assemblages like epidote, prehnite, chlorite, and others are
extremely important to understand in order to study the evolution of the geothermal system. Future
studies work can provide insight on the redox reactions taking place in the Karaha-Telaga Bodas
geothermal system. Changes in Fe3+/Fe2+ ratio in altered samples can provide information about
changes in geothermal fluids, which could affect the productivity of the geothermal system.
Similar methods can be applied to other geothermal systems.
Future studies could also investigate the circumstances under which high-temperature
magmatic vapors with SO2/H2S ratios produce oxidizing fluids that could produce Fe3+, which
could signal the existence of a magmatic component in the geothermal fluid system. This study
could lead to other scientific investigations such as measuring stable oxygen isotopes in hydrous
minerals and provide information about fluid chemistry, such as the mixing of magmatic and
meteoric waters.
Understanding the development of alteration mineralogy in geothermal systems is useful
in characterizing the potential energy production of a geothermal system. The methods outlined in
the study and in future studies can also be applied and refined for Enhanced Geothermal Systems
(EGS) and could provide valuable information about the chemical reactions taking place in an
evolving EGS system. According to the U.S. Department of Energy, EGS could power 100 million
American homes, even if production falls short of this goal, EGS could still contribute significantly
to U.S. energy production. Application of this technology abroad could significantly reduce
greenhouse gas emissions and encourage sustainable international development at the same time.
36
IX. ACKNOWLEDGEMENTS
I would like to thank my outstanding advisers Philp Candela, Philip Piccoli, and Joseph
Moore for being incredibly patient, brilliant, and flexible with me on my first rigorous scientific
endeavor. Thank you Frank Dulong and Palma Jarboe at the USGS for XRD analysis, the late
Naotatsu Shikazono for his work on iron-bearing alteration mineralogy in geothermal systems,
University of Maryland Geology Department for teaching me all the geology I know, Nivea
Magalhães for helping me with sample preparation, and my family and friends for encouraging me
to pursue my love for geology and the NSF EAR 1348010 awarded to Piccoli and Candela.
37
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Geothermal Resources, p. 1-24.
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and silicate melt: Contributions to Mineralogy and Petrology, v. 147, p 470-483.
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39
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40
Appendix A: Method for Deriving Statements of Equilibria by J.B. Thompson Jr.
The J.B. Thompson Jr. Method (1982) is uses Gauss-Jordan elimination to add and subtract system
components from phase components using linear algebra. Phase components are written in terms of their
chemical potential and the chemical potential of the system components. Once the set of linear equations is
defined using the phase components and system components that describe the phases present in the system,
the matrix can be reduced to solve for potential chemical reactions taking place. The number of statement
of equilibrium for a given matrix is determined by the difference between phase components and system
components. The statement of equilibrium can be added and subtracted from one another to produce
additional statements of equilibrium.
In addition to chemical formulas, exchange components can be used to represent an element
exchanges with in the phases, an example of this is the Tschermak exchange Al2Si-1Mg-1, a silica and
magnesium atom are substituted for two aluminum atoms. The following matrices were calculated in order
to first address the potential chemical reactions occurring among iron bearing minerals in drill core T-2.
The bolded numbers in the smaller matrices indicate equations used for calculating statements of
equilibrium.
Phases = 9
Components = 7
Reactions = 2
Phase SiO2 Al2O3 CaO MgO FeO O2 H2O
Ca2Al2Si3O10(OH)2 3 1 2 0 0 0 1
Ca2Al3Si3O12(OH) 3 1.5 2 0 0 0 0.5
Mg5AlAlSi3O10(OH)8 3 1 0 5 0 0 4
SiO2 1 0 0 0 0 0 0
O2 0 0 0 0 0 1 0
H2O 0 0 0 0 0 0 1
FeAl-1 0 -0.5 0 0 1 0.25 0
FeMg-1 0 0 0 -1 1 0 0
Al2Si-1Mg-1 -1 1 0 -1 0 0 0
Phase Al2O3 CaO MgO
Ca2Al2Si3O10(OH)2 –
H2O – 3SiO2 –
[Al2Si-1Mg-1 + SiO2 –
(FeMg-1 - (FeAl-1 –
0.25O2))]
1 2 0
Ca2Al3Si3O12(OH) –
0.5H2O – 3SiO2 –
1.5[Al2Si-1Mg-1 +
SiO2 – (FeMg-1 -
(FeAl-1 – 0.25O2))]
1.5 2 0
Mg5AlAlSi3O10(OH)8
– 4H2O – 3SiO2 +
5[FeMg-1 - (FeAl-1 –
0.25O2)] - [Al2Si-
1Mg-1 + SiO2 –
1 0 5
41
(FeMg-1 - (FeAl-1 –
0.25O2))]
[(FeMg-1 - (FeAl-1 –
0.25O2)]- [(FeMg-1 -
(FeAl-1 – 0.25O2)]
0 0 -1
[Al2Si-1Mg-1 + SiO2 –
(FeMg-1 - (FeAl-1 –
0.25O2))]- [Al2Si-
1Mg-1 + SiO2 –
(FeMg-1 - (FeAl-1 –
0.25O2))]
1 0 -1
Reactions:
1) Ca2Al2Si3O10(OH)2 – H2O – 3SiO2 – [Al2Si-1Mg-1 + SiO2 – (FeMg-1 - (FeAl-1 – 0.25O2))] =
Ca2Al3Si3O12(OH) – 0.5H2O – 3SiO2 – 1.5[Al2Si-1Mg-1 + SiO2 – (FeMg-1 - (FeAl-1 – 0.25O2))]
Ca2Al2Si3O10(OH)2 + 𝟏
𝟐Al2Si-1Mg-1 +
𝟏
𝟐SiO2 +
𝟏
𝟐FeAl-1 =
𝟏
𝟐H2O + FeMg-1 +
𝟏
𝟖O2 + Ca2Al3Si3O12(OH)
2) Mg5AlAlSi3O10(OH)8 – 4H2O – 3SiO2 + 2[FeMg-1] + 5[FeAl-1 - 1
4O2] =7[Al2Si-1Mg-1 + SiO2 +
2(FeMg-1) – (FeAl-1 - 1
4O2)]
Mg5AlAlSi3O10(OH)8 + 12FeMg-1 + 3O2 = 4H2O + 10SiO2 + 12FeAl-1 + 7Al2Si-1Mg-1
Phases = 9
Components = 7
Reactions = 2
Phase TiO2 CaO SiO2 Fe2O3 FeO Al2O3 H2O
Ca2Fe3Si3O12(OH) 0 2 3 1.5 0 0 0.5
Ca2Al3Si3O12(OH) 0 2 3 0 0 1.5 0.5
Fe6Si4O10(OH)8 0 0 4 0 6 0 4
Fe5Al2Si3O10(OH)8 0 0 3 0 5 1 4
CaTiSiO5 1 1 1 0 0 0 0
TiO2 1 0 0 0 0 0 0
SiO2 0 0 1 0 0 0 0
O2 0 0 0 2 -4 0 0
H2O 0 0 0 0 0 0 1
42
Phase Fe2O3 FeO Al2O3
Ca2Fe3Si3O12(OH) –
3SiO2 – 0.5H2O –
2(CaTiSiO5 - TiO2 -
SiO2)
1.5 0 0
[Ca2Al3Si3O12(OH) –
3SiO2 – 0.5H2O –
2(CaTiSiO5 - TiO2 -
SiO2)] -
[Ca2Al3Si3O12(OH) –
3SiO2 – 0.5H2O –
2(CaTiSiO5 - TiO2 -
SiO2)]
0 0 1.5
[Fe6Si4O10(OH)8 –
4SiO2 – 4H2O] -
[Fe6Si4O10(OH)8 –
4SiO2 – 4H2O]
0 6 0
Fe5Al2Si3O10(OH)8 –
3SiO2 - 4H20 –
(2/3)[Ca2Al3Si3O12(OH)
– 3SiO2 – 0.5H2O –
2(CaTiSiO5 - TiO2 -
SiO2)] –
(5/6)(Fe6Si4O10(OH)8 –
4SiO2 – 4H2O)
0 5 1
O2 +
(2/3)(Fe6Si4O10(OH)8 –
4SiO2 – 4H2O)
2 -4 0
Reactions:
1) Ca2Fe3Si3O12(OH) – 3SiO2 – 0.5H2O – 2(CaTiSiO5 - TiO2 - SiO2) – (3/4)[ O2 +
(2/3)(Fe6Si4O10(OH)8 – 4SiO2 – 4H2O)] = 0
Ca2Fe3Si3O12(OH) + 𝟏
𝟑 Fe6Si4O10(OH)8 +
𝟏𝟏
𝟑 SiO2 = Ca2Fe5Si8O22(OH)2 +
𝟓
𝟔 H2O +
𝟑
𝟒 O2
2) Fe5Al2Si3O10(OH)8 – 3SiO2 - 4H20 – (2/3)[Ca2Al3Si3O12(OH) – 3SiO2 – 0.5H2O – 2(CaTiSiO5 -
TiO2 - SiO2)] – (5/6)(Fe6Si4O10(OH)8 – 4SiO2 – 4H2O) = 0
Fe5Al2Si3O10(OH)8 + SiO2 + 𝟒
𝟑 CaTiSiO5 =
𝟏
𝟑 H2O +
𝟐
𝟑 Ca2Al3Si3O12(OH) +
𝟒
𝟑 TiO2 +
𝟓
𝟔 Fe6Si4O10(OH)8
Phases = 8
Components = 6
Reactions = 2
Phase CaO Al2O3 Fe2O3 FeO SiO2 H2O
Ca2Fe3Si3O12(OH) 2 0 1.5 0 3 0.5
43
Ca2Al3Si3O12(OH) 2 1.5 0 0 3 0.5
Fe6Si4O10(OH)8 0 0 0 6 4 4
Ca2Fe5Si8O22(OH)2 2 0 0 5 8 1
Al2Si-1Fe-1 0 1 0 -1 -1 0
SiO2 0 0 0 0 1 0
O2 0 0 2 -4 0 0
H2O 0 0 1 0 0 1
Phase CaO Al2O3 Fe2O3
Ca2Fe3Si3O12(OH) –
3SiO2 – 0.5H2O –
[Ca2Fe5Si8O22(OH)2 –
8SiO2 – H2O – (5/6)(
Fe6Si4O10(OH)8 –
4SiO2 – 4H2O)]
2 0 1.5
Ca2Al3Si3O12(OH) –
3SiO2 – 0.5H2O –
[Ca2Fe5Si8O22(OH)2 –
8SiO2 – H2O –
(5/6)(Fe6Si4O10(OH)8
– 4SiO2 – 4H2O)] –
1.5[Al2Si-1Fe-1 + SiO2
+ (1/6)(
Fe6Si4O10(OH)8 –
4SiO2 – 4H2O)]
2 1.5 0
[Ca2Fe5Si8O22(OH)2 –
8SiO2 – H2O – (5/6)(
Fe6Si4O10(OH)8 –
4SiO2 – 4H2O)] -
[Ca2Fe5Si8O22(OH)2 –
8SiO2 – H2O – (5/6)(
Fe6Si4O10(OH)8 –
4SiO2 – 4H2O)]
2 0 0
[Al2Si-1Fe-1 + SiO2 +
(1/6)(Fe6Si4O10(OH)8
– 4SiO2 – 4H2O)] -
[Al2Si-1Fe-1 + SiO2 +
(1/6)(Fe6Si4O10(OH)8
– 4SiO2 – 4H2O)]
0 1 0
O2 +
(2/3)(Fe6Si4O10(OH)8
– 4SiO2 – 4H2O)
0 0 2
Reactions:
1) Ca2Fe3Si3O12(OH) – 3SiO2 – 0.5H2O – [Ca2Fe5Si8O22(OH)2 – 8SiO2 – H2O – (5/6)(
Fe6Si4O10(OH)8 – 4SiO2 – 4H2O)] – (3/4)[O2 + (2/3)(Fe6Si4O10(OH)8 – 4SiO2 – 4H2O)] = 0
44
Ca2Fe3Si3O12(OH) + 𝟏
𝟑 Fe6Si4O10(OH)8 +
𝟏𝟏
𝟑 SiO2 = Ca2Fe5Si8O22(OH)2 +
𝟓
𝟔 H2O +
𝟑
𝟒 O2
2) Ca2Al3Si3O12(OH) – 3SiO2 – 0.5H2O – [Ca2Fe5Si8O22(OH)2 – 8SiO2 – H2O –
(5/6)(Fe6Si4O10(OH)8 – 4SiO2 – 4H2O)] – 1.5[Al2Si-1Fe-1 + SiO2 + (1/6)( Fe6Si4O10(OH)8 – 4SiO2
– 4H2O)] = 0
Ca2Al3Si3O12(OH) + 𝟕
𝟏𝟐 Fe6Si4O10(OH)8 +
𝟕
𝟔 SiO2 = Ca2Fe5Si8O22(OH)2 +
𝟏𝟏
𝟔 H2O +
𝟑
𝟐Al2Si-1Fe-1
Phases = 8
Components = 6
Reactions = 2
Phase CaO FeO Fe2O3 Al2O3 SiO2 H20
Ca2Fe3Si3O12(OH) 2 0 1.5 0 3 0.5
CaFe2Si2O8 1 0 1 0 2 0
Fe2+Fe3+2O4 0 1 1 0 0 0
Fe6Si4O10(OH)8 0 6 0 0 4 4
SiO2 0 0 0 0 1 0
H2O 0 0 0 0 0 1
AlFe-1 0 0 -0.5 0.5 0 0
Al2Fe-1Si-1 0 -1 0 1 -1 0
Phase CaO Fe2O3 Al2O3
Ca2Fe3Si3O12(OH) –
3SiO2 –(1/2)H2O –
(3/2)[Fe2+Fe3+2O4 –
(1/6)( Fe6Si4O10(OH)8
– 4SiO2 – 4H2O)]
2 1.5 0
CaFe2Si2O8 – 2SiO2 –
[Fe2+Fe3+2O4 –
(1/6)(Fe6Si4O10(OH)8 –
4SiO2 – 4H2O)]
1 1 0
Fe2+Fe3+2O4 –
(1/6)[Fe2+Fe3+2O4 –
Fe6Si4O10(OH)8 –
4SiO2 – 4H2O]
0 1 0
AlFe-1 – (1/2)[Al2Fe-
1Si-1 + SiO2 +
(1/6)[Fe2+Fe3+2O4 -
Fe6Si4O10(OH)8 –
4SiO2 – 4H2O]
0 -0.5 0.5
Al2Fe-1Si-1 + SiO2 +
(1/6)[Fe6Si4O10(OH)8 –
4SiO2 – 4H2O]
Reactions:
45
1) Ca2Fe3Si3O12(OH) - 1
2H2O -
3
2[Fe3O4 -
1
6 (Fe6Si4O10(OH)8 – 4SiO2 – 4H2O)] = 2[CaFe2Si2O8 –
2SiO2 – (Fe3O4 - 1
6 [Fe6Si4O10(OH)8 – 4SiO2 – 4H2O])
Ca2Fe3Si3O12(OH) + 𝟏
𝟐 Fe3O4 +
𝟒
𝟑 SiO2 = 2CaFe2Si2O8+
𝟏
𝟏𝟐 Fe6Si4O10(OH)8 +
𝟏
𝟔H2O
2) AlFe-1 - 1
2[Al2Fe-1Si-1 + SiO2 +
1
6 (Fe6Si4O10(OH)8 – 4SiO2 – 4H2O) +
1
2(Fe3O4 -
1
6 [Fe6Si4O10(OH)8
– 4SiO2 – 4H2O]) = 0
3) AlFe-1 + 𝟏
𝟔 SiO2 +
𝟐
𝟑 H2O +
𝟏
𝟐 Fe3O4 =
𝟏
𝟔 Fe6Si4O10(OH)8 +
𝟏
𝟐Al2Fe-1Si-1
Appendix B Thin Section Scans (optical)
All sample numbers are based on the depth from the surface of the drill core. Thin sections are
27 x 46 mm.
Sample 396 m Sample 889 m Sample 961 m Sample 980 m Sample 1,044 m Sample 1,117 m
Sample 1,193 m Sample 1,249 m Sample 1,378
m (A)
Sample 1,378 m
(B)
47
Barite
Calcite
Chalcopyrite
Chlorite
Chloroapatite
Epidote
Appendix C: Representative Energy Dispersive Spectroscopy Images
48
Hematite/Magnetite
Ilmenite
Plagioclase
Pyrite
Titanite
Quartz
Note: there is no EDS image for amphibole.
49
Appendix D: Wavelength Dispersive Spectroscopy Data for Epidote, Chlorite, Plagioclase, and
Amphibole
Epidote
Detection limit for epidote (ppm)
Oxide Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3
Epidote 160 190 100 130 220 120 230 230 150
Sample 396 m Wavelength Dispersive Spectroscopy Composition (wt %)
No. Description Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3 Total
1a
elongate
traverse,
points auto
selected,
each 13.5
µm apart
0.09 0.12 0.06 23.89 38.59 0.21 12.04 BD 23.57 98.57
0.02 0.06 0.42 23.07 38.21 0.64 9.96 0.43 25.00 97.81
0.13 0.06 0.10 23.64 37.94 0.09 11.13 0.31 24.55 97.95
0.03 0.18 0.13 23.48 38.03 0.29 10.72 0.11 25.31 98.27
BD 0.05 0.02 24.42 38.36 0.09 11.95 0.23 24.26 99.39
0.01 0.08 0.06 24.25 38.17 0.11 10.77 0.31 25.40 99.16
0.01 0.05 0.03 24.59 38.59 0.05 10.24 0.20 25.33 99.08
0.05 0.09 0.23 23.79 38.50 0.48 10.39 0.26 24.75 98.55
0.02 0.06 0.02 24.24 38.33 0.05 9.80 0.37 25.64 98.53
0.01 0.13 0.03 24.43 37.87 0.11 12.42 0.03 23.44 98.47
BD 0.08 0.04 24.62 38.29 0.11 11.63 0.07 24.25 99.10
0.01 0.03 0.03 24.58 38.44 0.06 10.42 0.05 25.37 98.98
BD 0.06 0.01 23.70 37.94 0.05 10.60 0.19 24.54 97.08
0.09 0.06 0.06 24.19 37.84 0.02 9.42 0.18 25.67 97.54
1b
short
traverse,
points auto
selected
each 6.87
µm apart
0.03 0.21 0.01 24.61 38.39 0.06 8.20 0.03 27.28 98.83
BD 0.04 0.03 24.50 38.23 0.02 9.60 0.09 26.12 98.64
0.01 0.05 0.09 24.34 38.50 0.10 10.90 0.23 24.74 98.98
BD 0.04 0.03 24.49 38.31 0.08 10.61 0.31 24.94 98.81
0.01 0.07 0.04 24.26 37.88 0.05 11.48 0.10 23.96 97.85
0.09 0.29 0.07 24.17 37.87 0.04 8.13 0.04 27.05 97.75
2
traverse
across
epidote
grain
towards
plagioclase
grain points
taken 9.94
µm apart
0.05 0.11 0.02 24.23 37.94 0.09 11.51 0.19 24.18 98.32
0.05 0.06 0.03 23.99 37.97 0.04 10.91 0.05 25.20 98.29
0.09 0.35 0.04 22.89 37.78 0.08 10.62 0.01 24.97 96.82
0.10 0.24 0.05 23.05 37.11 0.05 12.04 0.08 24.02 96.73
0.04 0.13 0.03 23.60 37.99 0.06 10.30 0.05 25.13 97.31
0.28 0.13 0.08 22.14 32.96 0.05 11.28 0.03 20.82 87.78
0.03 0.11 0.05 24.16 37.77 0.07 11.87 0.05 24.04 98.14
0.04 0.29 0.05 21.75 36.43 0.17 10.48 0.05 23.33 92.59
0.08 0.13 0.19 23.61 37.66 0.29 11.74 0.11 23.95 97.74
0.09 0.11 0.04 24.32 37.75 0.06 11.79 0.04 24.06 98.25
3
core 0.02 0.06 0.03 24.49 37.61 0.06 10.24 0.27 25.25 98.02
core BD 0.04 0.02 24.01 38.12 0.03 9.63 0.13 25.66 97.64
rim 0.04 0.22 0.01 23.74 38.41 0.04 10.66 0.10 24.74 97.97
rim 0.06 0.12 0.07 24.28 37.51 0.03 9.50 0.07 25.42 97.07
4
core BD 0.21 0.03 24.44 37.67 0.07 9.26 0.06 26.18 97.91
core 0.02 0.35 0.05 23.52 38.48 0.50 14.21 0.03 21.62 98.78
rim 0.38 0.09 0.24 12.83 50.72 12.79 15.28 0.19 5.24 97.78
5
core BD 0.14 0.03 23.83 37.96 0.07 11.55 0.02 24.22 97.82
rim BD 0.17 0.02 23.92 38.40 0.23 11.18 BD 24.97 98.90
rim 0.03 0.28 0.01 24.15 38.64 0.21 10.07 0.04 25.88 99.29
50
rim 2.24 0.09 0.06 19.53 42.46 0.04 6.58 0.09 25.73 96.82
rim 0.62 0.10 0.10 21.94 38.65 0.17 9.57 0.20 23.65 95.00
Sample 396 m Wavelength Dispersive Spectroscopy Relative Uncertainty due to Counting Statistics
No. Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3
1a
18.72 14.33 22.72 0.4 0.4 7.89 0.69 439.28 0.51
68.63 30.25 4.91 0.41 0.4 3.61 0.76 5.59 0.5
12.84 30.36 13.56 0.4 0.41 15.57 0.72 7.63 0.5
51.84 10.01 11.87 0.4 0.41 6.05 0.73 18.93 0.49
313.31 30.96 56.53 0.4 0.4 15.45 0.69 9.26 0.51
134.05 22.31 21.35 0.4 0.41 13.49 0.73 7.51 0.49
177.95 35.79 41.2 0.39 0.4 27.28 0.75 11.05 0.49
29.12 18.72 7.4 0.4 0.4 4.33 0.75 9.1 0.5
91.86 29.2 70.12 0.4 0.4 24.84 0.77 6.61 0.49
225.26 13.44 32.62 0.4 0.41 13.08 0.68 80.62 0.52
100 20.14 30.82 0.39 0.4 12.7 0.7 28.99 0.51
162.27 58.41 43.62 0.4 0.4 21.29 0.74 45.37 0.49
100 27.15 98.66 0.4 0.41 26.88 0.73 11.71 0.5
16.06 27.06 20.62 0.4 0.41 60.43 0.79 11.89 0.49
1b
55.68 9.32 109.73 0.39 0.4 21.49 0.84 61.41 0.47
100 47.03 34.91 0.39 0.4 48.95 0.77 21.15 0.48
169.75 32.44 14.62 0.4 0.4 14.65 0.72 9.8 0.5
100 48.22 37.86 0.39 0.4 16.37 0.73 7.59 0.49
101.23 23.21 27.87 0.4 0.41 23.38 0.7 22.84 0.51
15.67 6.8 18.7 0.4 0.41 32.91 0.85 49.68 0.47
2
26.33 15.33 70.79 0.4 0.4 14.99 0.7 11.31 0.5
28.26 26.91 37.42 0.4 0.41 31.25 0.72 43.69 0.49
17 6.09 30.61 0.41 0.41 17.33 0.73 366.14 0.5
17.37 8.11 26.7 0.41 0.41 26.28 0.69 25.02 0.51
42.29 14.43 37.25 0.4 0.41 21.96 0.75 41.88 0.49
7.25 14.02 16.9 0.41 0.43 28.86 0.71 56.4 0.55
60.58 16.98 23.68 0.4 0.41 18.57 0.69 38.47 0.51
41.06 7.39 25.7 0.42 0.41 9.33 0.74 40.44 0.51
18.28 13.57 8.46 0.4 0.41 6.18 0.69 20.14 0.51
17.75 15.41 27.2 0.4 0.41 22.55 0.69 51.73 0.51
3
82.4 29.81 34.5 0.39 0.41 21.58 0.75 8.42 0.49
100 43.83 48.07 0.4 0.4 42.34 0.77 17.04 0.49
30.34 8.59 106.46 0.4 0.4 30.89 0.73 21.56 0.5
26.5 14.51 17.52 0.4 0.41 37.56 0.78 30.01 0.49
4
100 8.65 42.13 0.39 0.41 18.89 0.79 31.94 0.48
72.49 6.1 23.71 0.4 0.4 4.36 0.63 70.44 0.54
5.68 18.66 6.8 0.55 0.34 0.72 0.61 10.74 1.17
5
100 12.77 39.14 0.4 0.41 20.24 0.7 116.24 0.5
426.61 10.96 53.95 0.4 0.4 7.37 0.71 684.36 0.5
50.99 6.92 110.66 0.4 0.4 7.83 0.76 51.57 0.49
1.78 21.01 22.74 0.44 0.38 30.45 0.95 21.64 0.48
3.92 18.73 13.51 0.42 0.4 9.24 0.78 11.36 0.51
Sample 888 m Wavelength Dispersive Spectroscopy Composition (wt %)
No. Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3 Total
17 0.01 0.05 0.01 24.53 38.41 0.16 8.96 BD 26.40 98.53
51
18 0.01 0.03 0.01 24.40 38.11 0.03 8.85 BD 26.28 97.71
19 0.02 0.13 0.02 24.21 37.79 0.10 8.43 0.01 26.10 96.80
20 0.01 0.10 0.03 24.34 37.72 0.10 8.72 0.03 26.16 97.21
21 0.11 0.09 0.03 23.92 37.84 0.21 10.66 BD 24.73 97.61
22 0.09 0.09 0.01 23.89 37.77 0.15 10.71 BD 24.59 97.30
23 0.13 0.27 0.03 22.02 40.62 0.08 7.36 BD 26.57 97.08
24 0.05 0.32 0.04 24.01 37.53 0.04 8.62 0.19 26.56 97.36
25 0.02 0.14 0.05 24.07 38.50 0.08 7.04 0.01 27.38 97.29
26 BD 0.08 0.02 24.43 38.33 0.11 8.37 BD 26.32 97.66
27 0.05 0.07 0.03 24.41 38.09 0.13 9.98 BD 25.08 97.83
28 0.02 0.11 0.01 23.21 39.63 0.45 11.63 0.03 22.91 97.99
29 0.06 0.09 0.05 23.86 38.02 0.36 11.45 0.02 23.16 97.06
30 BD 0.06 0.01 24.08 38.23 0.10 10.38 0.09 25.01 97.97
31 0.01 0.09 0.01 24.30 38.62 0.10 8.55 0.03 26.61 98.31
32 BD 0.09 0.04 24.26 38.28 0.13 9.71 BD 25.84 98.35
33 0.01 0.03 0.02 23.87 37.99 0.28 11.98 BD 23.30 97.48
34 BD 0.17 0.03 24.14 38.07 0.17 9.67 BD 25.28 97.54
35 0.01 0.13 0.04 23.94 37.96 0.18 10.05 0.06 24.72 97.10
36 0.01 0.04 0.02 23.92 38.01 0.10 10.93 0.04 24.73 97.80
37 0.01 0.15 0.02 24.19 38.68 0.05 6.23 0.09 28.18 97.60
38 BD 0.05 0.04 24.66 39.21 0.08 8.83 BD 27.08 99.95
39 BD 0.04 0.03 24.42 39.01 0.07 10.15 BD 26.02 99.74
40 0.08 0.07 0.01 23.91 38.76 0.11 9.82 BD 25.87 98.62
41 0.06 0.09 BD 23.94 38.85 0.11 9.72 0.03 25.70 98.52
42 BD 0.04 0.02 24.11 38.70 0.06 9.09 BD 26.48 98.50
43 0.01 0.10 BD 24.16 38.52 0.04 9.38 BD 26.18 98.40
Sample 961 m Wavelength Dispersive Spectroscopy Composition (wt %)
No. Description Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3 Total
6 core 0.01 0.02 0.01 25.13 38.65 0.04 7.43 0.02 28.14 99.45
7 core 0.01 0.08 0.02 24.99 38.88 0.03 9.05 0.02 27.07 100.13
8 core 0.01 0.12 0.01 24.63 38.82 0.06 10.83 0.05 25.85 100.37
9 core 0.01 0.14 0.03 25.04 37.63 0.21 10.20 2.80 23.40 99.46
10 core 0.02 0.03 0.01 24.65 38.62 0.08 10.72 0.03 25.79 99.95
11 core 0.02 0.08 0.03 24.33 38.34 0.25 14.06 BD 22.65 99.77
12 core 0.05 0.05 0.08 24.40 38.72 0.07 10.11 0.05 25.89 99.41
13 core 0.02 0.12 0.04 24.35 38.42 0.41 12.39 BD 23.97 99.72
14 core BD 0.04 0.03 24.72 39.40 0.02 9.98 BD 26.94 101.13
15 core BD 0.13 BD 24.54 38.23 0.17 11.79 BD 24.43 99.30
16 core 0.02 0.12 0.02 24.44 38.05 0.30 14.47 BD 22.11 99.53
Sample 961 m Wavelength Dispersive Spectroscopy Relative Uncertainty due to Counting Statistics
No. Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3
6 141.7 67.7 119.42 0.39 0.4 30.07 0.89 102.04 0.46
7 215.87 23.25 60.95 0.39 0.4 42.71 0.8 99.07 0.47
8 155.57 14.83 113.84 0.39 0.4 22.61 0.73 43.47 0.49
9 148.8 12.55 44.8 0.39 0.41 8.05 0.75 1.54 0.51
10 79.57 55.05 109.26 0.39 0.4 16.83 0.73 76.48 0.49
11 100.62 21.25 35.48 0.4 0.4 6.89 0.63 100 0.53
52
12 31.79 33.31 17.46 0.4 0.4 19.94 0.75 41.5 0.49
13 66.19 15.08 30.33 0.4 0.4 4.91 0.68 100 0.51
14 1111.3 38.8 40 0.39 0.4 57.07 0.76 923.72 0.48
15 700 14.04 302.66 0.39 0.4 9.14 0.7 483.85 0.5
16 77.78 15.26 51.51 0.4 0.41 6 0.62 100 0.53
Sample 961 m Distance from Vein Wavelength Dispersive Spectroscopy Composition (wt %)
No. Distance
(mm) Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3 Total
V1 0.42 BD 0.05 0.02 24.70 38.92 0.08 10.45 0.05 26.30 100.566
0.44 0.03 0.03 BD 24.88 38.73 0.05 10.56 0.05 26.02 100.359
V2 0.71 0.04 0.13 0.03 24.13 37.88 0.13 10.05 0.02 26.46 98.873
0.70 0.05 0.10 0.04 24.34 37.78 0.20 12.29 BD 23.63 98.447
V3 0.73 0.04 0.18 0.06 23.82 37.87 0.35 13.96 BD 22.96 99.247
0.73 0.02 0.12 0.03 24.46 37.52 0.21 12.54 BD 23.54 98.445
V4 0.80 0.01 0.07 0.03 23.99 38.44 0.45 11.99 BD 24.78 99.744
0.80 0.03 0.17 0.03 24.23 38.50 0.26 12.31 BD 24.24 99.767
V5 0.83 BD 0.09 0.04 24.38 38.37 0.07 10.31 BD 26.34 99.601
0.83 BD 0.20 0.01 24.32 38.25 0.16 11.69 BD 25.24 99.878
V6 0.87 0.09 0.04 0.06 24.58 39.45 0.10 10.19 0.08 26.14 100.722
0.87 0.01 0.05 0.04 24.40 38.57 0.27 13.64 0.03 23.61 100.616
V7 1.05 0.01 0.06 0.04 23.74 37.82 0.29 16.87 BD 20.63 99.457
1.05 0.03 0.03 0.03 24.02 37.99 0.28 16.68 BD 20.71 99.767
V8 1.16 0.01 0.11 0.02 24.56 38.46 0.27 13.01 BD 23.71 100.148
1.16 0.07 0.12 0.04 24.18 38.89 0.28 13.75 BD 22.88 100.206
V9 1.76 0.01 0.15 0.04 24.05 38.44 0.14 12.41 0.03 24.96 100.224
1.79 0.03 0.04 0.02 24.75 38.70 0.11 10.41 0.02 26.10 100.165
V10 2.17 BD 0.18 0.03 24.36 38.18 0.11 10.40 BD 25.84 99.110
2.17 BD 0.17 0.02 24.18 37.80 0.20 12.64 0.01 24.09 99.118
V11 2.17 BD 0.18 0.02 24.67 38.54 0.23 13.11 BD 22.89 99.646
2.17 0.02 0.08 0.02 24.25 38.50 0.30 14.57 BD 22.50 100.240
V12 1.82 0.01 0.16 0.01 24.56 38.10 0.29 12.69 0.05 23.47 99.338
1.82 0.04 0.15 0.05 24.07 38.16 0.33 12.83 0.03 23.15 98.829
V13 0.85 0.02 0.11 0.03 24.57 38.38 0.19 13.18 BD 23.32 99.782
0.84 BD 0.23 0.04 24.20 38.55 0.03 11.88 BD 25.24 100.161
V14 0.35 0.04 0.01 0.04 24.67 38.51 0.03 12.93 BD 24.30 100.522
0.35 0.05 0.02 0.03 24.60 38.75 0.05 12.75 BD 24.20 100.453
V15 0.36 0.01 0.08 0.02 24.11 38.03 0.27 15.15 BD 22.10 99.768
0.36 BD 0.09 0.02 24.47 38.74 0.16 11.86 BD 24.98 100.309
V16 3.10 0.08 0.03 0.02 24.47 38.96 0.13 11.32 BD 25.25 100.244
3.09 0.02 0.19 0.01 24.13 39.00 0.06 10.06 0.04 26.97 100.471
Sample 961 m Wavelength Dispersive Spectroscopy Relative Uncertainty due to Counting Statistics
No. Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3
V1 2109.5 33.82 65.22 0.39 0.4 16.2 0.74 40.42 0.48
44.05 53.7 1526.44 0.39 0.4 26.27 0.73 37.59 0.48
V2 43.37 14.29 36.18 0.4 0.41 10.98 0.76 106.04 0.48
27.32 17.19 31.31 0.4 0.41 8.13 0.68 100 0.51
V3 33.2 9.81 21.77 0.4 0.4 5.58 0.63 100 0.52
53
88.81 13.83 38.14 0.39 0.41 7.8 0.67 100 0.51
V4 202.67 25.57 42.31 0.4 0.4 4.58 0.69 100 0.5
57.99 11.15 35.21 0.4 0.4 6.78 0.68 434.56 0.5
V5 732.58 19.89 26.32 0.4 0.4 19.36 0.74 100 0.48
100 9.2 83.05 0.39 0.4 9.35 0.7 100 0.49
V6 17.58 36.7 22.19 0.39 0.4 14.07 0.75 26.52 0.48
116.86 33.41 32.63 0.39 0.4 6.42 0.64 75.39 0.51
V7 196.46 30.26 26.49 0.4 0.41 6.19 0.57 100 0.55
46.63 50.9 40.64 0.4 0.4 6.52 0.58 100 0.55
V8 180.28 16.27 47.19 0.39 0.4 6.73 0.66 100 0.51
23.04 14.99 28.92 0.4 0.4 6.51 0.64 100 0.52
V9 115.43 12.49 31.42 0.4 0.4 10.35 0.68 75.62 0.5
44.2 44.84 63.62 0.39 0.4 13.16 0.74 124.19 0.48
V10 100 9.97 42.82 0.39 0.4 11.65 0.75 100 0.48
100 10.34 46.77 0.4 0.41 7.87 0.67 135.58 0.51
V11 100 10.02 53.09 0.39 0.4 7.35 0.66 100 0.52
61.8 21.18 52.97 0.39 0.4 6.1 0.62 100 0.53
V12 144.16 11.05 129.1 0.39 0.4 6.36 0.67 40.69 0.51
34.71 12.42 21.96 0.4 0.4 5.6 0.66 57.55 0.52
V13 92.74 17.09 40.36 0.39 0.4 8.74 0.66 100 0.52
2193.16 8.03 29.17 0.4 0.4 48.59 0.69 100 0.49
V14 38.32 314.29 28.08 0.39 0.4 41.76 0.66 100 0.5
28.67 82.34 40.62 0.39 0.4 22.88 0.67 100 0.51
V15 265.75 22.14 78.42 0.4 0.41 6.79 0.61 100 0.53
100 21.39 55.31 0.4 0.4 9.37 0.69 100 0.5
V16 19.1 68.02 62.02 0.4 0.4 11.66 0.71 100 0.49
63.9 10.27 177.43 0.4 0.4 23.69 0.76 47.54 0.48
Sample 980 m Distance from Vein Wavelength Dispersive Spectroscopy Composition (wt %)
No. Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3 Total
44 0.01 0.24 0.08 24.10 38.82 0.09 7.35 0.02 27.75 98.46
45 BD 0.08 0.05 24.48 38.49 0.05 6.71 BD 28.19 98.04
46 0.02 0.15 0.01 23.64 37.77 0.12 12.55 BD 22.66 96.91
47 0.02 0.15 0.01 23.63 37.74 0.12 12.68 BD 22.69 97.03
48 0.08 0.15 0.02 23.24 38.56 0.12 12.58 0.03 22.63 97.41
49 0.08 0.19 0.02 22.97 38.53 0.11 13.02 0.02 22.21 97.16
50 0.13 0.19 0.02 22.54 37.43 0.14 8.46 BD 26.64 95.55
51 BD 0.09 0.01 24.39 37.93 0.10 6.86 BD 27.78 97.17
52 0.01 0.16 0.01 24.33 38.40 0.32 7.00 0.01 28.05 98.29
53 0.01 0.21 0.03 24.29 39.08 0.09 8.08 BD 27.41 99.19
54 0.01 0.21 0.01 23.76 37.71 0.31 13.57 0.02 22.32 97.92
55 0.01 0.21 0.03 23.72 37.75 0.09 11.96 0.03 23.44 97.24
56 0.03 0.17 0.04 24.11 38.26 0.08 10.42 BD 25.13 98.25
57 0.03 0.10 0.02 23.50 37.49 0.14 15.59 BD 20.74 97.62
58 0.03 0.09 0.03 24.56 38.59 0.06 10.31 0.02 24.85 98.55
59 0.05 0.29 0.03 24.40 38.88 0.05 7.97 BD 27.41 99.07
60 0.02 0.16 BD 24.51 38.85 0.30 9.34 0.01 26.02 99.21
61 0.29 0.24 0.03 23.53 38.66 0.07 8.88 BD 26.96 98.67
62 BD 0.12 0.02 24.51 38.44 0.06 10.64 0.06 25.48 99.32
63 BD 0.37 BD 24.53 37.34 0.06 9.86 2.28 23.43 97.87
64 0.42 0.14 0.01 23.59 39.37 0.05 8.36 BD 27.11 99.06
65 BD 0.14 0.01 24.40 38.67 0.10 11.42 BD 24.91 99.67
54
66 0.03 0.11 0.02 24.23 37.32 0.03 12.82 BD 23.00 97.56
67 0.02 0.18 BD 24.38 38.76 0.07 9.41 0.01 26.13 98.95
68 BD 0.23 0.03 24.68 38.92 0.12 6.87 BD 28.21 99.05
69 0.01 0.27 0.03 24.05 38.24 0.06 11.50 0.01 24.57 98.75
70 BD 0.44 0.01 23.79 38.23 0.02 9.65 BD 26.17 98.32
71 0.02 0.24 0.02 24.05 38.29 0.09 10.78 BD 24.49 97.97
72 0.02 0.18 BD 24.09 38.74 0.09 9.54 0.05 25.82 98.54
73 0.01 0.15 0.03 24.26 38.24 0.07 10.47 0.18 25.10 98.52
74 0.03 0.06 0.03 24.26 38.22 0.10 10.79 BD 24.82 98.30
75 BD 0.07 0.03 24.70 38.23 0.03 7.64 BD 27.78 98.47
76 0.02 0.11 0.03 24.55 38.38 BD 7.58 0.05 27.65 98.38
55
Chlorite
Detection limit for chlorite (ppm)
Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3
Chlorite 180 180 110 130 160 120 210 230 140
Sample 396 m Wavelength Dispersive Spectroscopy Composition (wt %)
No. Description Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3 Total
1
traverse,
points
manually
selected
0.04 0.09 0.90 0.10 28.43 19.93 19.47 0.10 19.28 88.34
0.05 0.09 1.56 0.19 29.53 16.03 18.94 0.17 18.36 84.91
0.86 0.10 0.65 1.08 32.76 16.21 18.31 0.04 21.56 91.57
0.03 0.11 1.14 0.12 28.98 17.06 20.10 0.09 19.15 86.79
0.16 0.08 3.27 0.39 28.16 15.97 18.59 0.20 15.35 82.17
0.09 0.04 8.75 0.09 34.86 11.58 19.28 4.21 12.63 91.53
2
traverse,
points
manually
selected
0.05 0.12 1.23 0.14 28.79 17.29 20.85 0.09 19.18 87.74
0.03 0.11 0.62 0.11 29.58 18.89 20.76 0.06 20.82 90.99
0.03 0.06 2.13 0.13 31.21 18.06 20.26 0.19 18.73 90.80
0.02 0.08 0.71 0.09 28.37 18.36 20.66 0.04 20.27 88.60
0.04 0.11 2.56 0.15 32.20 19.19 19.24 0.21 18.02 91.72
3
traverse,
points
manually
selected
0.03 0.08 1.30 0.16 28.44 17.50 20.40 0.09 18.76 86.74
0.03 0.10 1.41 0.16 28.43 17.09 20.19 0.07 18.75 86.22
0.02 0.12 2.04 0.15 31.19 17.49 19.28 0.18 19.02 89.49
DB 0.10 1.89 0.15 30.02 17.55 19.68 0.15 18.28 87.81
0.24 0.11 0.83 0.36 26.82 19.12 19.91 0.07 18.33 85.79
Sample 396 m Wavelength Dispersive Spectroscopy Relative Uncertainty due to Counting Statistics
No. Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3
1
44.41 17.88 3.23 12.72 0.49 0.58 0.53 19.89 0.62
30.02 19.63 2.35 8.18 0.48 0.64 0.54 12.35 0.63
3.19 16.82 3.83 2.16 0.45 0.64 0.55 46.75 0.57
46.35 14.9 2.8 11.67 0.48 0.63 0.52 22.56 0.62
11.26 20.35 1.58 4.4 0.49 0.65 0.54 11.5 0.69
18.88 42.75 0.95 15.81 0.43 0.77 0.53 1.2 0.75
2
33.51 14.18 2.66 9.93 0.49 0.62 0.51 24.1 0.62
44.78 15.88 3.9 12.88 0.48 0.59 0.51 30.57 0.59
62.33 26.66 1.99 10.63 0.47 0.61 0.52 11.2 0.62
81.23 20.46 3.69 15.5 0.49 0.6 0.51 54.41 0.6
42.91 14.69 1.8 9.71 0.46 0.59 0.53 10 0.64
3
54.06 20.82 2.61 8.82 0.49 0.62 0.52 23.13 0.62
40.18 17.61 2.5 9.39 0.49 0.63 0.52 28.17 0.62
108.33 13.97 2.03 9.81 0.46 0.61 0.53 11.72 0.62
100 16.77 2.1 9.4 0.47 0.61 0.53 13.97 0.63
7.71 15.07 3.34 4.79 0.51 0.59 0.52 28.54 0.63
56
Sample 888 m Wavelength Dispersive Spectroscopy Composition (wt %)
No. Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3 Total
C9 0.00 0.22 0.16 0.09 24.23 7.62 31.74 0.00 21.24 85.30
C10 0.01 0.27 0.05 0.10 25.33 7.81 31.76 0.02 22.14 87.49
C11 0.06 0.26 0.13 0.25 21.97 11.44 26.56 0.01 19.08 79.78
C12 0.04 0.24 0.59 0.28 29.81 10.44 25.56 0.03 24.17 91.17
C13 0.02 0.24 0.05 0.20 24.73 11.11 25.95 0.01 21.02 83.33
C14 0.13 0.16 0.07 0.46 25.99 10.57 25.72 0.01 23.53 86.63
C15 0.00 0.23 0.07 0.26 26.87 8.78 27.82 0.01 23.84 87.89
C16 0.03 0.28 0.03 0.42 23.03 9.38 25.75 0.00 19.41 78.33
C17 0.06 0.24 0.26 0.31 26.68 11.44 25.08 0.00 22.63 86.70
C18 0.04 0.24 0.23 0.34 26.41 11.38 24.81 0.02 22.28 85.73
C19 0.02 0.27 0.04 0.25 26.60 11.87 27.06 0.00 22.30 88.41
C20 0.00 0.31 0.05 0.15 23.72 11.30 26.85 0.00 19.86 82.24
C21 0.00 0.31 0.06 0.15 23.97 11.48 27.50 0.00 19.99 83.47
Sample 961 m Distance from Vein Wavelength Dispersive Spectroscopy Composition (wt %)
No. Distance
(mm) Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3 Total
C1 0.31 0.31 0.22 0.05 0.09 26.63 13.79 27.15 0.03 18.36 86.64
0.32 0.29 0.22 0.03 0.13 26.64 13.01 27.28 0.02 18.37 86.01
C2 0.73 0.38 0.16 0.06 0.21 28.51 13.48 27.64 0.01 18.40 88.85
0.73 1.06 0.12 0.07 0.33 30.45 14.32 22.57 0.00 19.00 87.93
C3 0.74 0.29 0.19 0.07 0.08 26.91 12.78 27.96 0.00 17.85 86.12
0.74 0.36 0.20 0.04 0.13 28.33 15.45 25.10 0.00 18.62 88.23
C4 2.22 0.09 0.04 0.06 24.60 39.72 0.10 10.15 0.08 26.59 101.43
2.22 0.29 0.16 0.08 0.18 28.44 14.62 26.36 0.14 17.96 88.22
C5 1.86 0.29 0.16 0.09 0.22 28.95 15.31 25.67 0.08 17.92 88.72
1.77 0.19 0.18 0.06 0.13 29.12 17.13 23.64 0.10 18.37 88.91
C6 0.48 0.27 0.26 0.04 0.17 29.15 16.74 23.00 0.09 18.49 88.21
0.52 0.21 0.20 0.05 0.08 27.49 14.13 27.49 0.00 18.68 88.35
C7 0.51 0.22 0.19 0.06 0.13 29.05 16.31 24.39 0.00 18.38 88.72
1.77 0.28 0.24 0.06 0.58 27.18 17.64 22.95 0.01 17.07 86.01
C8 1.78 0.24 0.17 0.09 0.69 28.38 16.42 23.59 0.01 18.31 87.91
Sample 961 m Wavelength Dispersive Spectroscopy Relative Uncertainty due to Counting Statistics
No. Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3
C1 7.12 8.45 26.7 15.98 0.51 0.72 0.44 55.25 0.63
7.86 8.51 38.17 10.49 0.51 0.74 0.44 80.99 0.63
C2 5.92 11.14 22.74 7.43 0.49 0.72 0.44 239.31 0.63
2.92 14.43 17.58 4.96 0.47 0.69 0.49 100 0.62
C3 7.47 9.76 17.43 17.8 0.5 0.75 0.44 965.2 0.64
6.09 8.69 32.52 11.28 0.49 0.67 0.46 100 0.63
C4 17.58 36.7 22.19 0.39 0.4 14.07 0.75 26.52 0.48
6.82 10.85 16.38 8.2 0.49 0.69 0.45 15.26 0.64
57
C5 6.9 11.37 15.3 6.88 0.48 0.67 0.46 24.85 0.64
10.44 10.99 20.74 10.81 0.48 0.63 0.48 20.97 0.63
C6 7.52 7.26 28.39 8.81 0.48 0.64 0.49 21.34 0.63
9.34 8.85 25.25 16.04 0.5 0.71 0.44 100 0.63
C7 9.25 9.56 21.71 10.64 0.48 0.65 0.47 100 0.63
7.45 7.36 21.95 3.27 0.5 0.62 0.49 222.24 0.66
C8 8.35 10.28 14.43 2.95 0.49 0.65 0.48 229.88 0.63
Sample 980 m Wavelength Dispersive Spectroscopy Composition (wt %)
No. Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3 Total
C22 0.04 0.36 0.05 0.14 28.80 15.70 23.99 0.02 19.90 89.00
C23 0.02 0.42 0.16 0.09 26.69 12.75 27.89 0.03 19.10 87.14
C24 0.03 0.44 0.03 0.22 27.29 15.87 21.96 0.00 19.46 85.29
C25 0.04 0.39 0.04 0.21 28.56 17.42 20.83 0.00 19.56 87.05
C26 0.01 0.35 0.04 0.18 27.65 17.17 23.46 0.02 18.40 87.27
C27 0.02 0.30 0.06 0.15 28.45 17.41 22.48 0.00 18.91 87.78
C28 0.01 0.32 0.05 0.18 26.63 16.66 21.15 0.00 17.69 82.68
C29 0.04 0.43 0.03 0.16 28.34 15.03 25.68 0.02 19.68 89.41
C30 0.01 0.43 0.11 0.12 28.01 14.85 25.71 0.03 20.11 89.37
C31 0.02 0.36 0.04 0.11 26.26 14.19 26.62 0.00 18.58 86.18
C32 0.01 0.42 0.08 0.15 26.41 14.56 23.70 0.03 18.20 83.57
C33 0.02 0.39 0.03 0.16 28.84 16.22 21.40 0.00 18.85 85.92
C34 0.01 0.46 0.04 0.15 27.61 14.80 25.12 0.03 19.21 87.43
C35 0.02 0.45 0.02 0.14 28.60 16.87 23.40 0.02 19.49 89.01
C36 0.08 0.35 0.04 0.40 30.46 16.50 23.12 0.01 19.96 90.91
C37 0.07 0.33 0.04 0.36 29.98 16.85 22.74 0.00 19.61 89.99
C38 0.12 0.20 0.07 0.19 28.22 16.41 23.55 0.01 18.86 87.63
C39 0.28 0.23 0.09 0.38 28.98 16.32 21.95 0.01 19.24 87.48
C40 0.03 0.40 0.04 0.31 30.25 17.53 21.02 0.02 19.60 89.22
C41 0.03 0.41 0.04 0.30 28.79 16.61 22.07 0.04 18.91 87.19
58
Plagioclase
Detection limit for plagioclase (ppm)
Oxide Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3
Plagioclase 180 180 110 130 210 130 220 210 160
Sample 396 m Wavelength Dispersive Spectroscopy Composition (wt %)
No. Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3 Total
1a
(elongate
traverse,
points
manually
selected)
2.86 0.01 0.20 14.59 49.36 0.03 0.21 31.63 98.88
2.87 0.14 14.96 49.80 0.04 0.57 0.04 31.84 100.27
3.61 0.16 13.27 51.64 0.08 0.53 0.03 29.97 99.29
3.22 0.09 13.88 51.04 0.07 0.58 0.04 30.98 99.90
3.29 0.01 0.16 14.11 50.58 0.05 0.53 0.03 31.18 99.94
3.65 0.01 0.14 13.06 52.21 0.07 0.53 0.06 30.05 99.79
2.62 0.02 0.11 14.67 49.80 0.07 0.50 0.02 31.72 99.54
2.10 0.07 16.29 48.09 0.03 0.52 0.02 33.13 100.27
2.13 0.02 0.09 16.18 48.07 0.01 0.55 32.89 99.95
2.45 0.09 15.34 48.86 0.02 0.57 0.01 32.18 99.52
2.58 0.04 0.11 15.23 49.15 0.07 0.59 0.03 32.16 99.95
3.10 0.15 14.37 50.42 0.05 0.55 0.05 31.32 100.01
2.10 0.09 16.56 47.71 0.02 0.56 0.03 32.98 100.04
2.21 0.04 0.08 15.98 48.32 0.05 0.54 0.01 32.70 99.93
2.67 0.01 0.13 15.25 49.04 0.04 0.57 0.02 31.85 99.57
2.39 0.01 0.13 15.39 48.65 0.07 0.56 0.02 32.47 99.69
2.86 0.17 14.47 49.89 0.03 0.48 0.03 31.69 99.61
2.89 0.02 0.16 14.42 49.71 0.03 0.45 0.01 31.57 99.26
4.48 0.01 0.32 11.63 53.73 0.04 0.43 0.04 29.39 100.06
2.13 0.12 16.10 48.11 0.01 0.10 33.69 100.27
1b (short
traverse,
points
manually
selected)
0.02 0.20 0.07 96.68 0.28 0.28 0.54 98.08
2.82 0.13 15.07 49.72 0.04 0.56 0.04 31.93 100.32
2.55 0.02 0.10 15.57 48.42 0.05 0.58 32.25 99.55
2.13 0.02 0.08 16.27 47.95 0.04 0.55 0.05 32.85 99.93
1.68 0.03 0.06 17.19 46.83 0.02 0.56 0.01 33.70 100.08
1.98 0.02 0.08 16.63 46.82 0.03 0.55 33.86 99.96
2.32 0.12 16.14 47.95 0.02 0.57 32.37 99.48
3.51 0.16 13.49 51.41 0.06 0.54 30.49 99.65
2.51 0.18 14.66 49.37 0.02 0.30 31.65 98.69
4.68 0.02 0.35 10.99 54.63 0.01 0.44 0.02 28.13 99.27
2
3.31 0.02 0.22 14.02 51.08 0.01 0.19 31.44 100.29
3.17 0.20 14.33 50.58 0.02 0.57 0.03 31.45 100.35
4.80 0.41 10.38 53.50 0.14 0.20 0.04 28.33 97.80
5.62 0.46 8.94 56.79 0.01 0.14 0.02 27.15 99.12
4.92 0.34 10.67 55.11 0.01 0.23 28.51 99.79
5.67 0.01 0.57 9.09 56.52 0.26 27.37 99.49
4.29 0.31 11.85 53.93 0.01 0.21 0.02 29.50 100.11
4.82 0.31 11.12 54.76 0.01 0.23 28.73 99.99
5.40 0.01 0.41 9.82 56.12 0.32 0.03 28.17 100.28
5.33 0.51 9.42 56.68 0.03 0.23 27.50 99.68
3.90 0.30 12.54 52.28 0.01 0.15 30.40 99.57
5.96 0.32 8.82 56.98 0.01 0.09 0.02 27.11 99.32
2.76 0.02 0.21 14.92 49.55 0.47 32.26 100.19
59
2.16 0.01 0.14 16.30 48.13 0.02 0.31 33.17 100.25
3
4.84 0.02 0.35 10.93 53.49 0.21 0.46 28.83 99.12
4.30 0.02 0.45 11.93 54.30 0.40 0.47 30.64 102.51
4.83 0.02 0.45 10.03 54.04 0.38 0.34 27.73 97.82
5.97 0.37 8.96 55.96 0.23 0.32 27.11 98.93
5.29 0.01 0.69 9.12 54.72 0.65 0.75 26.92 98.15
4
1.95 0.11 16.65 47.44 0.01 0.63 0.04 33.37 100.20
1.62 0.01 0.06 17.47 46.67 0.03 0.59 33.97 100.43
1.63 0.05 17.15 46.21 0.02 0.57 0.03 33.54 99.20
1.83 0.02 0.09 16.94 47.07 0.03 0.47 33.81 100.26
1.84 0.02 0.07 16.94 47.18 0.04 0.66 33.72 100.48
Sample 396 m Wavelength Dispersive Spectroscopy Relative Uncertainty due to Counting Statistics
No. Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3
1a
(elongate
traverse,
points
manually
selected)
1.4 109.85 8.13 0.51 0.35 38.88 9.83 100 0.43
1.39 100 10.21 0.51 0.35 28.87 4.48 50.46 0.43
1.23 100 9.01 0.54 0.34 15.67 4.88 69.29 0.44
1.31 100 15.05 0.53 0.35 18.25 4.35 43.9 0.43
1.29 126.83 9.78 0.52 0.35 24.56 4.48 61.57 0.43
1.22 105.58 10.44 0.54 0.34 16.24 4.55 30.9 0.44
1.46 75.77 12.55 0.51 0.35 17.28 4.86 116.89 0.42
1.65 391.31 19.14 0.48 0.36 36.57 4.87 78.91 0.41
1.65 97.79 13.86 0.49 0.36 107.47 4.55 100 0.42
1.52 100 14.24 0.5 0.36 50.62 4.45 197.6 0.42
1.48 34.05 12.39 0.5 0.35 18.47 4.25 67.87 0.42
1.33 441.47 9.75 0.52 0.35 24.28 4.57 34.32 0.43
1.66 1037.62 14.58 0.48 0.36 68.55 4.5 65.77 0.42
1.61 32.2 16.31 0.49 0.36 22.54 4.59 189.38 0.42
1.45 150.06 11.41 0.5 0.35 28.98 4.38 97.58 0.42
1.53 106.31 10.55 0.5 0.36 17.85 4.45 120.1 0.42
1.38 100 9.04 0.51 0.35 43.26 5.27 58.9 0.42
1.37 72.09 9.28 0.52 0.35 40.55 5.39 248.84 0.43
1.09 144.04 5.76 0.58 0.34 30.77 5.37 53.37 0.44
1b (short
traverse,
points
manually
selected)
47.83 100 8.24 16.08 0.23 5.56 7.28 100 4.14
1.4 318.12 10.73 0.5 0.35 26.52 4.55 50.32 0.42
1.47 92.26 13.1 0.5 0.36 25.15 4.41 100 0.42
1.65 80.79 16.61 0.48 0.36 27.61 4.72 34.63 0.42
1.88 53.63 20.66 0.47 0.36 54.12 4.37 126.33 0.41
1.71 86.33 15.74 0.48 0.36 35.25 4.61 364348.5 0.41
1.57 100 11.27 0.49 0.36 64.68 4.4 365171.8 0.42
1.26 100 9.44 0.54 0.35 20.95 4.64 100 0.43
1.49 100 8.49 0.51 0.35 45.28 7.58 100 0.43
1.07 88.43 5.43 0.6 0.33 91.74 5.37 72.8 0.45
1.64 1018.17 11.32 0.49 0.36 191.49 18.94 100 0.41
2
1.29 96.51 7.53 0.52 0.35 117.19 11.4 100 0.43
1.32 726.29 8.2 0.52 0.35 70.71 4.49 62.84 0.43
1.05 100 4.88 0.61 0.34 9.49 10.6 42.63 0.45
0.96 3.1E+08 4.86 0.66 0.33 74.07 15.18 86.11 0.46
1.04 100 5.64 0.6 0.33 161.35 9.39 100 0.45
0.96 105.95 4.13 0.66 0.33 100 8.34 100 0.46
1.12 100 5.93 0.57 0.34 107.89 10.49 97.53 0.44
1.05 100 6.17 0.59 0.33 106.7 9.62 599.01 0.45
60
0.99 142.14 5.07 0.63 0.33 466.37 6.95 65.09 0.45
0.99 100 4.37 0.64 0.33 43.72 9.79 100 0.46
1.18 100 6.07 0.55 0.34 119.07 13.43 100 0.43
0.93 100 5.73 0.67 0.33 133.46 22.81 85.9 0.46
1.41 79.56 7.46 0.51 0.35 100 5.36 100 0.42
1.61 138.02 10.98 0.48 0.36 52.12 7.13 100 0.41
3
1.05 92.6 5.55 0.59 0.34 7.38 5.12 100 0.45
1.11 78.34 4.77 0.57 0.34 4.7 5.14 1182.93 0.43
1.05 71.06 4.81 0.62 0.34 4.82 6.82 100 0.46
0.94 100 5.36 0.66 0.33 6.62 6.83 1191.87 0.46
0.99 149.16 3.66 0.65 0.33 3.42 3.6 100 0.46
4
1.73 100 12.31 0.48 0.36 78.63 4.14 54.82 0.41
1.9 109.85 19.05 0.47 0.37 33.6 4.56 418.98 0.41
1.9 100 24.3 0.47 0.37 54.44 4.42 69.13 0.41
1.77 95.09 14.05 0.48 0.36 40.79 5.02 100 0.41
1.78 67.71 18.63 0.48 0.36 29.38 4.02 100 0.41
Sample 888 m Wavelength Dispersive Spectroscopy Composition (wt %)
No. Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3 Total
6 1.92 0.03 0.07 17.26 47.01 0.04 0.48 BD 33.37 100.19
7 1.98 0.03 0.04 17.22 47.59 0.02 0.49 0.03 33.54 100.95
8 4.71 0.02 0.18 12.42 53.60 0.06 0.55 0.05 29.33 100.93
9 2.32 BD 0.08 16.74 48.25 0.07 0.41 0.01 33.18 101.06
10 1.87 0.01 0.04 17.50 46.89 0.04 0.47 0.01 34.00 100.84
11 1.95 0.01 0.03 17.10 47.11 0.07 0.52 BD 33.92 100.72
12 2.11 0.02 0.07 16.91 47.57 0.04 0.54 BD 33.38 100.64
13 2.33 0.02 0.07 16.59 48.02 0.03 0.52 0.01 32.64 100.23
14 2.32 BD 0.07 16.38 47.60 0.06 0.50 BD 32.64 99.57
15 2.53 0.01 0.08 15.89 48.59 0.06 0.51 0.02 32.57 100.25
16 1.95 BD 0.09 16.94 47.24 0.02 0.51 BD 33.28 100.03
17 2.40 0.01 0.08 16.29 47.92 0.06 0.53 0.01 32.76 100.07
18 2.45 0.01 0.04 16.15 48.34 0.06 0.56 BD 32.53 100.13
19 2.54 0.01 0.05 15.90 48.59 0.06 0.58 BD 32.45 100.19
20 4.20 BD 0.16 12.79 52.58 0.04 0.63 BD 29.75 100.15
21 2.14 0.01 0.05 16.65 47.77 0.03 0.49 0.02 32.90 100.05
Sample 961 m Wavelength Dispersive Spectroscopy Composition (wt %)
No. Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3 Total
5
(elongate
traverse,
points
manually
selected)
1.09 0.02 0.07 18.00 45.67 0.05 0.50 35.23 100.62
1.38 0.06 17.60 46.88 0.01 0.40 35.01 101.34
0.31 0.01 16.23 0.01 65.38 0.11 0.01 18.74 100.81
0.28 0.01 13.75 0.03 66.65 0.13 19.26 100.11
2.78 0.09 14.87 50.10 0.09 0.67 32.40 101.00
1.13 0.06 18.39 46.01 0.59 0.01 35.50 101.70
0.88 0.02 0.05 18.85 45.25 0.01 0.47 0.01 35.34 100.89
1.11 0.01 0.03 18.19 45.81 0.43 0.03 35.30 100.91
1.43 0.07 17.65 46.77 0.09 0.43 0.02 34.25 100.71
61
Sample 961 m Wavelength Dispersive Spectroscopy Relative Uncertainty due to Counting Statistics
No. Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3
5
(elongate
traverse,
points
manually
selected)
2.41 100.49 18.64 0.46 0.37 26.28 5.04 100 0.4
2.1 364.03 19.36 0.47 0.36 117.19 5.98 100 0.4
5.34 109.85 0.7 105.78 0.3 100 17.07 322.28 0.55
5.43 250 0.76 34.48 0.29 100 14.81 100 0.54
1.41 100 15.04 0.51 0.35 14.24 3.99 3663.43 0.42
2.32 340.48 21.06 0.46 0.37 269.92 4.31 175.85 0.4
2.77 64.93 22.59 0.45 0.37 181.66 5.26 191.05 0.4
2.37 231.66 36.1 0.46 0.37 321.73 5.52 69.84 0.4
2.05 100 18.46 0.47 0.36 13.54 5.52 104.28 0.41
Sample 980 m Wavelength Dispersive Spectroscopy Composition (wt %)
No. Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3 Total
22 0.74 BD 0.02 19.38 44.75 0.04 0.45 BD 35.82 101.20
23 0.58 BD 0.02 19.68 44.19 0.03 0.42 BD 35.89 100.80
24 0.61 0.01 0.04 19.54 44.36 0.02 0.43 0.01 35.48 100.50
25 0.64 0.02 0.02 19.56 44.34 BD 0.42 BD 35.58 100.60
26 0.66 0.03 0.03 19.28 44.18 0.07 0.43 0.03 35.40 100.12
27 0.70 0.01 0.04 19.24 44.28 0.02 0.45 BD 35.58 100.31
28 0.50 0.01 0.02 19.48 43.62 0.02 0.39 BD 35.16 99.21
29 0.51 BD 0.04 19.57 44.09 BD 0.38 BD 35.75 100.35
30 1.25 0.01 0.04 18.47 45.78 0.02 0.57 0.02 34.74 100.89
31 1.30 BD 0.02 18.17 45.88 0.04 0.54 BD 34.61 100.57
32 1.35 0.02 0.04 18.14 45.59 0.01 0.59 0.01 34.39 100.14
33 2.58 BD 0.07 15.73 48.17 0.02 0.18 BD 32.48 99.24
34 2.74 BD 0.06 16.07 49.11 0.02 0.21 BD 33.61 101.82
35 0.78 0.03 0.03 19.33 45.05 0.04 0.41 0.02 35.43 101.13
36 0.76 0.02 0.03 19.22 44.50 BD 0.43 0.02 35.23 100.20
37 1.37 BD 0.06 15.05 40.42 0.03 0.45 BD 34.23 91.63
38 0.73 BD 0.02 19.27 44.72 0.01 0.46 0.03 35.46 100.70
39 0.75 BD 0.03 18.91 44.32 0.11 0.64 BD 35.10 99.84
40 2.23 BD 0.05 11.73 43.24 0.10 0.13 0.02 34.75 92.25
41 0.72 0.01 0.02 19.43 44.57 BD 0.47 0.02 35.60 100.85
42 0.70 BD 0.01 19.50 44.57 0.03 0.46 BD 35.40 100.67
43 0.71 0.01 0.03 19.27 44.71 0.05 0.40 BD 35.75 100.92
44 0.50 BD 0.03 19.53 43.15 0.05 0.39 0.02 35.48 99.15
45 1.22 BD 0.03 18.37 45.84 0.06 0.50 0.01 34.62 100.65
46 2.29 BD 0.08 16.72 47.78 0.01 0.14 0.01 33.38 100.41
47 0.57 BD 0.02 19.72 44.01 0.01 0.39 BD 35.76 100.48
48 0.66 0.02 0.02 19.39 44.48 0.07 0.40 BD 35.78 100.82
49 0.62 0.03 0.01 19.56 44.45 0.03 0.41 BD 35.85 100.95
50 0.74 0.03 0.01 19.30 44.44 0.01 0.42 BD 35.74 100.69
51 0.76 0.01 0.01 19.24 44.62 BD 0.41 BD 35.61 100.68
52 0.75 0.01 0.03 19.40 44.56 0.02 0.42 BD 35.79 100.99
53 0.69 0.02 0.01 19.47 44.53 0.03 0.44 0.01 35.84 101.05
54 0.57 0.03 0.02 19.37 43.75 0.03 0.39 0.02 35.35 99.52
55 1.03 0.01 0.03 18.92 45.17 0.05 0.49 BD 35.04 100.75
56 1.80 0.01 0.05 17.04 46.40 0.04 0.60 0.02 33.26 99.23
57 1.47 BD 0.05 18.26 45.94 0.07 0.62 BD 34.08 100.48
62
58 3.10 0.03 0.09 14.98 49.80 0.01 0.19 0.03 32.41 100.64
59 2.32 BD 0.04 16.36 48.47 0.01 0.56 BD 32.93 100.69
60 1.73 0.02 0.04 17.50 46.84 0.05 0.70 0.05 33.59 100.51
61 1.68 0.01 0.05 17.62 46.70 0.06 0.61 0.04 33.43 100.19
62 1.19 0.01 0.01 18.55 45.40 0.01 0.56 BD 34.52 100.24
63 1.41 BD 0.06 18.01 45.93 0.04 0.60 0.01 34.30 100.36
64 1.66 BD 0.05 17.59 46.72 0.01 0.09 0.02 34.66 100.79
65 1.22 0.02 0.03 18.37 45.82 0.05 0.56 BD 34.53 100.60
66 2.15 0.01 0.04 16.71 47.57 0.04 0.59 0.01 33.06 100.18
67 1.53 0.02 0.05 17.93 48.78 0.04 0.36 0.01 36.29 104.99
68 1.10 0.02 0.03 18.49 45.11 0.04 0.54 0.01 34.69 100.03
69 0.97 BD 0.03 18.76 44.82 0.02 0.56 0.01 35.00 100.18
70 0.13 0.38 0.05 0.29 26.76 10.85 25.86 BD 20.14 84.45
71 0.64 BD 0.03 10.47 38.43 0.05 0.43 0.01 24.92 74.98
72 1.12 0.01 0.07 18.24 45.08 0.19 0.70 0.02 34.40 99.83
73 1.72 0.01 0.02 17.48 47.19 0.02 0.64 0.02 34.10 101.20
74 0.95 0.03 0.06 18.36 49.56 0.07 0.54 0.01 37.81 107.39
75 2.12 0.01 0.09 16.50 47.89 0.10 0.55 0.01 33.04 100.32
76 1.92 0.01 0.03 17.00 47.45 0.06 0.55 BD 33.85 100.88
77 1.67 0.02 0.03 16.06 42.53 0.04 2.32 BD 31.40 94.07
78 1.85 BD 0.03 16.80 47.33 0.01 0.11 BD 34.22 100.36
79 1.87 BD 0.06 17.29 47.19 0.02 0.61 0.05 33.63 100.73
80 2.33 BD 0.06 16.97 48.32 0.06 0.67 0.02 33.41 101.84
81 2.02 0.01 0.05 16.99 47.38 BD 0.14 0.01 34.01 100.61
82 1.16 0.01 0.04 18.49 45.34 0.06 0.61 BD 34.36 100.06
83 1.12 BD 0.05 18.50 45.47 0.01 0.56 0.02 34.84 100.55
84 1.06 0.02 0.02 18.74 45.38 0.05 0.59 0.01 35.01 100.88
85 1.00 0.02 0.06 18.53 44.39 0.15 0.49 0.02 34.24 98.91
86 1.06 BD 0.03 18.73 45.20 0.04 0.56 BD 34.95 100.59
87 1.10 0.05 0.04 18.52 44.98 0.09 0.61 BD 34.66 100.05
88 1.66 BD 0.04 17.29 42.59 0.07 0.59 0.02 32.04 94.30
89 1.67 BD 0.05 17.62 46.10 0.05 0.57 0.01 34.14 100.20
90 2.12 0.02 0.05 16.91 47.64 BD 0.29 BD 33.62 100.67
91 0.82 BD 0.02 19.35 44.75 0.03 0.45 BD 35.47 100.88
92 0.76 0.03 0.02 19.34 44.81 0.02 0.50 BD 35.39 100.86
93 2.38 BD 0.04 16.46 48.43 BD 0.07 BD 33.33 100.71
94 2.04 0.02 0.03 16.79 47.49 0.04 0.59 0.01 33.26 100.28
95 1.63 0.01 0.05 17.73 46.70 0.05 0.56 BD 34.29 101.03
96 3.44 0.01 0.07 14.54 50.57 0.08 0.58 0.02 30.87 100.17
97 2.58 0.02 0.09 15.81 48.72 0.01 0.11 BD 32.96 100.30
98 1.17 0.02 0.05 18.27 45.68 0.04 0.51 BD 34.15 99.88
99 1.57 0.02 0.06 17.68 46.53 0.06 0.59 BD 34.05 100.57
100 1.60 BD 0.04 17.72 46.18 0.01 0.56 BD 34.32 100.43
101 2.40 0.03 0.07 16.46 47.93 BD 0.09 BD 33.42 100.40
102 1.59 BD 0.05 17.81 46.50 0.02 0.57 BD 34.12 100.67
103 1.01 BD 0.02 18.92 45.38 0.05 0.53 BD 35.04 100.94
104 2.21 0.02 0.08 16.72 47.93 BD 0.39 0.01 33.17 100.53
105 2.30 0.03 0.09 16.50 48.30 0.11 0.56 0.01 33.26 101.17
Sample 1,249 m Wavelength Dispersive Spectroscopy Composition (wt %)
No. Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3 Total
63
106 2.66 BD 0.11 15.79 49.03 BD 0.52 0.04 32.66 100.81
107 1.46 BD 0.05 18.05 46.26 BD 0.16 BD 34.90 100.88
108 0.51 0.01 0.02 19.58 44.22 0.03 0.49 BD 35.70 100.55
109 0.76 0.01 0.06 19.26 44.76 0.02 0.49 BD 35.62 100.97
110 0.81 BD 0.03 19.06 44.96 0.09 0.49 BD 35.33 100.77
111 1.14 BD 0.05 18.57 45.79 0.02 0.41 0.01 34.99 100.98
112 0.84 0.01 0.02 19.11 45.01 0.04 0.48 0.01 35.46 100.99
113 0.78 0.01 0.03 18.97 45.10 0.05 0.44 BD 35.56 100.93
114 0.77 BD 0.01 19.18 44.85 0.08 0.47 BD 35.28 100.65
115 0.73 BD 0.03 19.06 44.71 0.04 0.47 BD 35.05 100.10
116 0.76 0.01 0.05 18.87 44.81 0.02 0.56 BD 35.12 100.20
117 1.17 BD 0.06 18.51 45.81 0.02 0.60 BD 35.26 101.44
118 0.76 0.02 0.03 19.02 44.56 0.04 0.48 BD 35.43 100.33
119 0.66 BD 0.04 19.28 44.28 0.02 0.47 BD 35.15 99.89
120 0.76 0.01 0.03 18.88 44.84 0.05 0.53 BD 35.39 100.49
121 0.82 0.01 0.02 18.91 44.93 0.02 0.48 BD 35.59 100.78
122 0.78 BD 0.02 18.99 44.71 0.02 0.52 0.01 35.25 100.30
123 0.81 BD 0.03 18.98 44.94 0.02 0.49 BD 35.21 100.50
124 0.83 0.01 0.03 19.02 44.99 0.03 0.52 BD 35.39 100.80
125 0.81 0.01 0.04 19.20 44.80 0.02 0.49 BD 35.51 100.88
126 0.87 BD 0.04 18.81 44.86 0.01 0.47 BD 35.41 100.46
127 1.16 0.03 0.04 18.25 45.72 0.08 0.23 BD 34.98 100.48
128 0.90 BD 0.03 18.84 44.76 0.02 0.62 0.01 35.33 100.52
129 2.05 0.01 0.08 16.71 47.50 0.01 0.47 0.02 33.42 100.27
130 1.59 0.01 0.05 17.69 46.28 0.01 0.74 BD 33.91 100.27
131 0.54 BD 0.03 19.61 44.40 0.02 0.47 BD 36.04 101.11
132 0.82 0.03 0.04 19.11 44.70 0.05 0.50 BD 35.65 100.91
133 0.80 0.01 0.03 19.12 44.75 0.01 0.49 BD 35.41 100.62
134 0.26 0.53 0.11 12.53 52.32 11.77 18.20 BD 3.09 98.81
135 0.85 0.02 0.05 19.02 44.77 BD 0.68 BD 35.30 100.70
136 2.72 0.02 0.10 15.50 49.32 0.25 0.83 0.03 31.62 100.40
137 0.67 BD 0.03 19.46 44.71 0.04 0.43 0.02 35.63 101.00
138 0.76 BD 0.02 19.13 45.05 0.03 0.45 BD 35.44 100.88
139 0.79 BD 0.03 19.14 44.80 0.02 0.49 BD 35.57 100.83
140 0.85 0.02 0.03 18.92 45.09 0.04 0.43 BD 35.70 101.06
141 0.78 BD 0.03 19.07 44.96 0.03 0.43 0.01 35.44 100.75
142 0.76 BD 0.03 19.17 44.88 0.04 0.41 BD 35.42 100.71
143 0.74 BD 0.05 19.18 44.92 0.04 0.44 BD 35.40 100.78
144 0.73 BD 0.04 19.34 44.65 0.03 0.44 BD 35.34 100.56
145 0.77 BD 0.03 19.27 44.73 0.03 0.42 0.01 35.78 101.03
146 0.70 BD 0.05 19.34 44.76 0.03 0.49 0.02 35.51 100.90
147 0.72 BD 0.04 19.32 44.99 0.02 0.46 BD 35.39 100.94
148 0.74 0.03 0.04 19.38 45.01 0.02 0.50 BD 35.77 101.48
149 0.02 BD 0.10 0.18 1.46 0.64 57.96 BD 1.11 61.48
150 0.73 BD 0.02 19.37 44.92 BD 0.55 BD 35.65 101.24
64
151 0.76 0.03 0.03 19.15 44.95 0.01 0.54 BD 35.28 100.75
152 0.73 0.01 0.03 19.39 44.67 0.02 0.53 BD 35.66 101.04
153 1.38 0.01 0.07 18.10 46.03 0.03 0.78 0.06 34.05 100.51
154 0.54 0.02 0.03 19.57 43.49 BD 0.46 BD 35.05 99.16
155 0.72 0.01 BD 19.37 44.89 0.04 0.47 0.02 35.40 100.92
156 0.70 BD 0.02 19.30 44.99 0.04 0.55 BD 35.60 101.20
157 2.10 0.01 0.09 16.90 47.70 0.03 0.95 0.01 33.41 101.19
158 0.69 BD 0.05 19.27 44.60 0.02 0.42 0.02 35.30 100.38
159 1.67 0.01 0.07 17.37 46.43 0.09 0.64 0.04 33.40 99.71
160 1.55 BD 0.07 17.69 46.24 0.05 0.68 0.04 33.26 99.59
161 1.40 0.02 0.09 17.90 46.09 0.03 0.69 BD 34.39 100.61
162 0.75 BD 0.06 19.10 44.49 0.03 0.51 0.03 35.10 100.07
163 0.69 BD 0.06 19.36 44.55 0.03 0.42 0.01 35.60 100.72
164 1.71 0.01 0.10 17.39 46.89 0.07 0.72 BD 33.94 100.84
165 1.86 BD 0.07 17.21 46.63 0.03 0.80 0.01 33.30 99.91
166 1.28 BD 0.06 18.36 46.17 0.07 0.64 BD 34.44 101.03
167 1.23 BD 0.07 18.36 45.79 0.06 0.66 0.02 34.29 100.48
168 1.64 BD 0.06 17.75 46.67 0.05 0.89 0.02 33.64 100.72
169 1.24 0.01 0.03 18.25 45.45 0.03 0.71 BD 34.47 100.19
170 0.59 BD 0.05 19.54 44.42 0.06 0.39 BD 35.46 100.49
171 0.57 0.01 0.02 19.63 44.45 0.14 0.48 BD 35.87 101.18
172 2.27 0.03 0.12 16.38 48.23 0.18 0.79 BD 32.18 100.19
173 2.53 BD 0.10 16.09 48.38 0.07 0.83 0.06 32.34 100.39
174 0.56 BD 0.04 19.69 44.42 0.02 0.51 0.01 35.86 101.11
175 0.61 BD 0.02 19.70 44.49 0.02 0.53 BD 35.56 100.92
176 2.66 BD 0.12 15.89 49.27 0.08 0.91 0.03 31.98 100.94
177 1.52 BD 0.08 17.89 46.59 0.01 0.33 0.02 34.76 101.20
Sample 1,378 m Wavelength Dispersive Spectroscopy Composition (wt %)
No. Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3 Total
178 4.86 BD 0.25 11.59 53.83 0.06 0.79 0.05 28.77 100.20
179 4.64 BD 0.22 12.09 53.12 0.06 0.79 0.06 29.06 100.04
180 4.84 BD 0.28 11.63 53.79 0.05 0.93 0.06 28.38 99.96
181 5.05 BD 0.26 11.38 54.09 0.05 0.89 0.02 28.20 99.93
182 3.94 BD 0.18 13.30 50.95 0.02 0.66 0.02 30.31 99.38
183 4.37 BD 0.20 12.55 52.06 0.01 0.65 BD 29.82 99.66
184 4.57 BD 0.20 12.24 53.05 0.04 0.34 BD 29.51 99.94
185 5.26 BD 0.30 10.80 56.00 BD 0.29 BD 27.67 100.34
186 3.45 0.01 0.30 14.18 49.86 BD 0.22 BD 31.14 99.18
187 4.73 0.01 0.28 12.04 53.73 0.01 0.30 BD 29.37 100.47
188 4.98 BD 0.27 11.61 54.01 0.01 0.36 0.01 29.14 100.39
189 2.71 BD 0.15 15.66 49.40 BD 0.19 BD 32.73 100.85
190 4.95 BD 0.31 11.37 53.79 0.03 0.37 0.01 28.43 99.26
191 5.17 0.02 0.30 11.09 54.88 BD 0.41 BD 28.37 100.25
65
192 4.92 BD 0.27 11.62 53.54 0.01 0.41 0.06 28.98 99.80
193 4.63 0.02 0.23 12.12 53.33 0.03 0.41 0.01 29.74 100.53
194 4.94 BD 0.27 11.63 54.06 0.03 0.43 0.01 28.85 100.23
195 3.19 0.01 0.11 15.05 49.88 BD 0.57 0.03 31.88 100.71
196 4.32 0.03 0.53 12.57 52.95 BD 0.58 0.06 29.72 100.77
197 2.89 BD 0.15 15.44 50.48 0.01 0.19 BD 33.29 102.45
198 2.89 BD 0.12 15.35 49.56 0.01 0.20 BD 32.22 100.34
66
Amphibole
Sample 1,249 m Wavelength Dispersive Spectroscopy Composition (wt %)
No. Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3 Total
1 0.80 0.18 0.24 12.76 53.54 19.16 6.22 0.43 3.81 97.13
2 0.73 0.22 0.21 12.58 53.89 19.40 5.53 0.42 3.52 96.51
3 1.11 0.34 0.16 12.45 51.50 16.85 8.32 0.21 7.07 98.00
4 0.87 0.24 0.21 12.38 53.14 18.22 8.28 0.28 4.34 97.97
5 1.02 0.28 0.22 12.22 52.03 17.18 8.76 0.27 5.18 97.15
6 0.67 0.27 0.15 12.38 54.59 16.34 9.00 0.46 3.87 97.73
7 0.90 0.19 0.19 12.81 53.36 18.65 7.11 0.34 4.37 97.92
8 0.67 0.24 0.16 12.28 53.44 17.49 9.61 0.32 3.75 97.98
9 0.86 0.17 0.27 12.85 53.30 19.25 6.17 0.42 4.22 97.51
10 0.70 0.17 0.28 12.97 55.00 18.87 6.22 0.39 3.74 98.34
11 0.81 0.30 0.20 11.82 51.78 17.64 9.54 1.90 3.99 97.98
12 1.25 0.19 0.23 13.19 51.62 17.32 6.32 0.59 7.39 98.09
13 0.68 0.32 0.11 11.85 54.03 18.60 8.50 0.43 3.02 97.54
14 0.84 0.22 0.20 12.70 54.32 19.58 6.21 0.27 4.08 98.42
15 1.02 0.19 0.27 12.58 52.42 18.86 6.48 0.41 4.81 97.04
16 0.85 0.22 0.25 12.69 52.62 18.30 7.22 0.40 4.32 96.87
17 1.17 0.24 0.21 12.75 52.00 18.73 6.72 0.50 5.53 97.85
18 1.01 0.21 0.21 12.99 50.96 16.40 7.83 0.38 8.00 97.99
19 1.05 0.27 0.19 12.37 51.86 17.29 8.80 0.16 6.00 97.99
20 1.33 0.26 0.26 12.62 51.11 18.44 6.95 0.57 6.32 97.86
21 1.26 0.27 0.21 12.82 51.40 16.72 6.87 0.48 7.78 97.79
22 0.80 0.32 0.20 12.69 54.11 19.53 5.27 0.41 3.53 96.87
23 0.70 0.46 0.17 12.23 54.87 20.59 4.85 0.41 2.95 97.24
24 1.07 0.37 0.13 11.94 51.49 17.70 8.64 0.29 5.15 96.78
25 0.79 0.35 0.16 12.27 52.78 18.05 8.05 0.24 4.04 96.73
26 0.78 0.37 0.17 11.99 51.43 15.77 9.88 0.33 6.71 97.43
27 0.83 0.40 0.15 12.18 51.22 15.86 11.65 0.20 5.56 98.05
28 1.00 0.25 0.20 11.99 52.44 18.56 7.80 0.35 4.72 97.30
29 0.90 0.19 0.24 12.71 52.86 17.66 7.86 0.38 5.36 98.16
30 1.00 0.24 0.23 12.77 52.27 18.83 6.51 0.48 4.88 97.20
31 0.79 0.36 0.16 12.74 53.31 18.66 7.37 0.23 4.05 97.67
32 0.87 0.30 0.18 11.91 52.58 17.83 8.87 0.39 4.80 97.75
33 0.85 0.39 0.13 11.72 52.58 17.53 9.45 0.35 4.17 97.17
34 0.53 0.43 0.14 12.52 55.72 20.96 4.95 0.42 2.19 97.87
35 0.52 0.51 0.13 12.42 55.89 20.37 5.38 0.36 2.24 97.81
36 0.28 0.24 0.17 11.85 50.17 10.31 21.03 0.09 4.04 98.18
37 0.26 0.23 0.16 12.59 51.60 11.58 18.73 0.08 3.54 98.75
38 0.32 0.44 0.09 12.21 56.24 20.51 4.90 0.27 1.27 96.26
39 0.36 0.39 0.12 12.41 56.09 20.67 5.06 0.24 1.50 96.83
40 0.70 0.41 0.15 10.54 53.86 19.19 8.96 0.32 3.16 97.30
41 0.59 0.32 0.16 12.16 54.91 19.97 5.52 0.32 2.62 96.58
42 0.43 0.45 0.13 12.44 55.52 20.73 4.79 0.29 2.14 96.92
43 0.73 0.40 0.13 12.71 53.74 19.49 5.34 0.27 3.97 96.77
44 0.58 0.36 0.17 12.25 55.15 20.48 5.31 0.31 2.49 97.11
45 0.59 0.40 0.17 12.21 55.24 20.71 5.17 0.31 2.63 97.43
67
46 1.05 0.38 0.21 11.42 52.27 17.93 9.57 0.38 5.10 98.31
47 0.71 0.41 0.17 11.98 52.81 16.55 10.97 0.34 3.79 97.72
Sample 1,378 m Wavelength Dispersive Spectroscopy Composition (wt %)
No. Na2O MnO K2O CaO SiO2 MgO FeO TiO2 Al2O3 Total
48 0.29 0.33 0.15 12.45 51.47 13.82 14.41 0.30 3.82 97.05
49 0.42 0.23 0.22 12.08 50.35 13.91 14.85 0.25 4.18 96.49
50 0.38 0.20 0.24 12.12 50.56 13.92 14.86 0.27 4.48 97.04
51 0.48 0.24 0.25 10.50 49.21 14.17 15.26 0.24 5.33 95.69
52 0.27 0.39 0.20 12.56 51.40 14.03 13.98 0.26 4.14 97.24
53 0.34 0.41 0.41 12.33 50.43 14.31 13.49 0.39 4.89 96.99
54 0.39 0.38 0.43 11.43 49.53 12.96 15.15 0.37 5.04 95.70
55 0.42 0.53 0.31 12.46 50.38 13.26 14.65 0.39 4.83 97.24
56 0.37 0.42 0.20 11.80 50.81 13.84 14.41 0.21 4.18 96.25
57 0.40 0.44 0.20 11.49 50.62 13.76 14.46 0.14 4.03 95.55
68
Appendix E: Hypothesis Testing for a Simple Linear Regression Model for Measuring the
Molar Ratio of Fe/Al in Chlorite and Epidote with Respect to Distance from Vein
Hypothesis Testing
H0: β0 > 0
H1: β0 ≤ 0
Chlorite:
�̂� = 1.055 – 0.066x
b1 = 𝑠𝑥𝑦
𝑠𝑥2 = -0.066
b0 = �̅� - b1�̅� = 1.055
Where,
𝑠𝑥𝑦 = ∑ (𝑥𝑖−�̅�)(𝑦𝑖−�̅�)𝑛
𝑖=1
𝑛−1 = -0.007
𝑠𝑥2=
∑ (𝑥𝑖−�̅�)2𝑛𝑖=1
𝑛−1 = 0.102
�̅� = ∑ 𝑥𝑖
𝑛𝑖=1
𝑛 = 1.066
�̅� = ∑ 𝑦𝑖
𝑛𝑖=1
𝑛 = 0.985
SSE = ∑ (𝑦𝑖 − �̂�𝑖)2𝑛𝑖=1 = (n-1)(𝑠𝑦
2 − 𝑠𝑥𝑦
2
𝑠𝑥2 ) = 0.078
𝑠𝜀2=
𝑆𝑆𝐸
𝑛−2 = 0.006
𝑠𝑏1=
𝑠𝜀
√(𝑛−1)𝑠𝑥2 = 0.070
t = 𝑏1− 𝛽1
𝑠𝑏1
= -0.950, therefore we reject H0: β0 > 0.
Epidote:
�̂� = 0.383 – 0.011x
69
b1 = 𝑠𝑥𝑦
𝑠𝑥2 = -0.011
b0 = �̅� - b1�̅� = 0.383
Where,
𝑠𝑥𝑦 = ∑ (𝑥𝑖−�̅�)(𝑦𝑖−�̅�)𝑛
𝑖=1
𝑛−1 = -0.007
𝑠𝑥2=
∑ (𝑥𝑖−�̅�)2𝑛𝑖=1
𝑛−1 = 0.594
�̅� = ∑ 𝑥𝑖
𝑛𝑖=1
𝑛 = 1.197
�̅� = ∑ 𝑦𝑖
𝑛𝑖=1
𝑛 = 0.369
SSE = ∑ (𝑦𝑖 − �̂�𝑖)2𝑛𝑖=1 = (n-1)(𝑠𝑦
2 − 𝑠𝑥𝑦
2
𝑠𝑥2 ) = 0.192
𝑠𝜀2=
𝑆𝑆𝐸
𝑛−2 = 0.006
𝑠𝑏1=
𝑠𝜀
√(𝑛−1)𝑠𝑥2 = 0.018
t = 𝑏1− 𝛽1
𝑠𝑏1
= -0.613, therefore we reject H0: β0 > 0.
70
Appendix F: X-Ray Diffractograms
71
72
73
74
75
76
Appendix G: Honor Code
I pledge on my honor that I have not given nor received any unauthorized assistance on this
assignment.
Emma Grace McConville
