CHAPTER 5
ANISOTROPY OF MAGNETIC SUSCEPTIBILITY
(AMS)
Page No.
5.1 Introduction 111
5.2 Magnetic Mineralogy of Lava Flows 113
5.3 The Effects of Time, Temperature and Weathering 114
5.4 Magnetic Foliation 115
5.5 Magnetic Lineation 116
5.6 Instrument Used 116
5.7 Measuring of Anisotropy of Magnetic Susceptibility 117
5.8 Methodology 118
5.9 Analysis of the AMS results 121
5.10 References 141
111
CHAPTER 5
ANISOTROPY OF MAGNETIC SUSCEPTIBILITY (AMS)
5.1 Introduction
Important works on the magnetic anisotropy of rocks were carried out during
the 1940s and 1950s (Ising, 1942; Graham, 1954). These authors first realized that
magnetic methods may be used to characterize the preferred orientation of minerals
within the rock samples. Ising studied varved clays in Sweden and noticed that the
magnetic susceptibility was higher on the bedding plane than orthogonally to it.
Graham recognized that the anisotropy of magnetic susceptibility (AMS) may be
regarded as a petrofabric element, he later extended the analysis to various
sedimentary rocks of the Appalachian Mountains and pointed out the existence of
distinct and systematic relationships of the magnetic properties with structural setting
(Graham, 1966). The studies progressively developed the following decades and a
first comprehensive review on magnetic anisotropy and its application in geology and
geophysics was published by (Hrouda, 1982). Over the past 20-30 years, researches
on magnetic anisotropy gained widespread use and were extended to examine the
fabric in a variety of sedimentary, igneous, and metamorphic rocks (Lanza and
Meloni, 2006; Hrouda, 2007).
Two principal mechanisms control the magnetic anisotropy of rocks. 1. Lattice
alignment of crystals with magnetocrystalline anisotropy, 2. Shape alignment of
ferromagnetic grains.
The magnetic anisotropy of rocks is often determined by means of the analysis,
of the anisotropy of the magnetic susceptibility (AMS), which is the significant
property that has found the most geophysical applications. The AMS of rocks is
controlled by preferentially oriented magnetic mineral grains and, therefore, it
contains information about both the grains susceptibilities and their orientation-
distribution. Knowing the composition of the rock forming minerals and their
magnetic anisotropy characteristics, it is possible to determine the spatial distribution
of the grains and the geological processes inference. A preferential orientation
distribution of mineral grains is in fact typical of almost all rock types and it develops
during various geological processes, such as water flow in sediments, magma flow in
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igneous rock, ductile deformation in metamorphic rocks, and even incipient strain in
the paramagnetic clay matrix of apparently undeformed fine-grained sediments.
All the materials are “susceptible” to become magnetized in the presence of an
applied magnetic field, and the magnetic susceptibility describes this transient
magnetism within a material sample. If the magnetic field is relatively weak, the
magnetization of a rock is a linear function of the intensity of this field. The low field
magnetic susceptibility is defined as the ratio of the induced magnetization (M, dipole
moment per unit volume or J, dipole moment per unit mass) to the applied low-
intensity magnetic field (H). Only for isotropic substances the induced magnetization
is strictly parallel to the applied field, and the magnetic susceptibility is a scalar. In
the general case of anisotropic media, like minerals and rocks, the induced
magnetization is not parallel to the applied field.
The magnetization of a rock induced in a weak magnetic field is a linear
function of the intensity of field
M1 = k11 H1 + k12 H2 + k13H3 M2 = k2l H1 + k22 H2 + k23 H3 M3 = k31 Hl + k32 H2 + k33 H3
where Mi (i = 1, 2, 3) are the components of the magnetization vector (in the
Cartesian coordinate system), Hj (j = 1, 2, 3) the components of the vector of the
intensity of magnetic field and the set of the constants kij (kij = kji) represents the
components of the symmetric tensor of second rank, called the susceptibility tensor.
The components of the susceptibility tensor are in general non zero, but there exists
such a Cartesian coordinate system in which the non-diagonal components of the
susceptibility tensor are zero and the above equations change into
M1 = k11 H1 M2 = k22 H2 M3 = k33 H3
The components k11, k22, k33 are called the principal susceptibilities and their
directions, as the principal directions. The principal susceptibilities are usually
referred to as the maximum, intermediate and minimum susceptibilities respectively.
Low-field anisotropy of magnetic susceptibility (AMS) is an increasingly used
petrofabric tool that allows us to solve a large number of problems of geological
interest. Although the sources of the AMS of any rock type ultimately reside in their
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mineral components, whether associated with their crystalline structure, the shape of
individual mineral grains or their distribution within a more or less isotropic matrix
(Hrouda, 1982, Tarling & Hrouda, 1993) The orientation of principal susceptibilities
represents distribution of magnetic minerals fabric in rock; however, the rock
composition and metamorphic grade may affect the anisotropy of magnetic
susceptibility and bulk susceptibility of rock type (Borradaile and Henry, 1997,
Nakamura and Borradaile, 2004). The bulk susceptibility (Km), anisotropy
susceptibility and other forms of magnetic anisotropy commonly play a great roll to
determine the state of strain and petrofabric, and are also used as strain indicators. The
AMS may be represented by magnitude ellipsoids, geometrically shaped by three
magnetic principal axes (K1≥ K2≥K3) those are closely related to the strain axes (λ1>λ2
>λ3). There are two elements, magnetic foliation ‘F’ (K1- K2 Plane) and magnetic
lineation ‘L’ (K1) (Tarling and Hrouda, 1993) and their anisotropy parameters are
described by eccentricity ‘Pj’ and its shape ‘T’.
5.2 Magnetic Mineralogy of Lava Flows
The magnitudes of bulk magnetic susceptibility (km) have large differences
among different lava flows or within the single lava flow. It depends upon the
different factors as source of lava flows, dominance and contribution of different
magnetic minerals. Different stages of lava flows also play vital role in contribution of
magnetic anisotropy. Exact discrimination of magnetic mineralogy and their
contribution for rock anisotropy property is difficult and it required detail analysis
although (Borradaile, 1988) and (Hrouda & Kahan, 1991) have shown that a small
amount of ferromagnetic minerals (~l volume %) is enough to dominate the magnetic
properties of a rock including its characteristic (km). Further (Tarling & Hrouda,
1993) suggest that, if km > 5x10-3SI is very likely that the contributions from
ferromagnetic minerals rather than paramagnetic and diamagnetic minerals. In other
case if km < 10-4SI the ferromagnetic contribution can be negligible and the
interpretation of the anisotropy is only relevant to the paramagnetic and diamagnetic
minerals fraction. For rocks with a bulk susceptibility intermediate between these two
extremes, a more detailed examination of the mineral content might be required
before drawing a valid petrofabric interpretation of the measured AMS (Canon-Tapia,
E 2004.) All mineral grains with in a rock contribute to its total susceptibility but
their individual influence depends upon the intrinsic susceptibility as well as on their
concentration (Hrouda and kahan, 1991)
Fig. 5.1 Mineral contribution to the susceptibility of a rock (After Hrouda
and kahan ,1991)
5.3 The Effects of Time, Temperature and Weathering
It is difficult to understand the importance of the changes that are induced
both temperature and time in the magnetic mineralogy and, hence, in the anisotropic
properties of the rock types. Temperature increases are usually the most effective, but
changes that occur as a consequence of the passage of time can be very significa
yet, being much more subtle, difficult to detect. In general, it is sediments that are
most sensitive to both temperature and the passage of time, reflecting their
heterogeneous composition and multifarious environmental history.
Most mineralogical changes induced by increasing temperature are likely to be
associated with an increased degree of metamorphism, particularly as the greenschist
grade is approached at some 250
also result in major fluctuations in local Eh
modifications of the mineralogy. Such changes will almost always result in a
noticeable modification of the mean susceptibility of the rocks affected, reflecting
either the creation or destruction of f
fabric is likely to be drastically altered. These thermochemical effects are most
114
their individual influence depends upon the intrinsic susceptibility as well as on their
(Hrouda and kahan, 1991) as shown in Fig. 5.1.
Fig. 5.1 Mineral contribution to the susceptibility of a rock (After Hrouda
and kahan ,1991)
5.3 The Effects of Time, Temperature and Weathering
It is difficult to understand the importance of the changes that are induced
both temperature and time in the magnetic mineralogy and, hence, in the anisotropic
properties of the rock types. Temperature increases are usually the most effective, but
changes that occur as a consequence of the passage of time can be very significa
yet, being much more subtle, difficult to detect. In general, it is sediments that are
most sensitive to both temperature and the passage of time, reflecting their
heterogeneous composition and multifarious environmental history.
ogical changes induced by increasing temperature are likely to be
associated with an increased degree of metamorphism, particularly as the greenschist
grade is approached at some 250-300˚C, but the migration of hot or cold fluids can
also result in major fluctuations in local Eh-pH conditions, with consequent
modifications of the mineralogy. Such changes will almost always result in a
noticeable modification of the mean susceptibility of the rocks affected, reflecting
either the creation or destruction of ferromagnetic minerals, and the mean shape of the
fabric is likely to be drastically altered. These thermochemical effects are most
their individual influence depends upon the intrinsic susceptibility as well as on their
Fig. 5.1 Mineral contribution to the susceptibility of a rock (After Hrouda
It is difficult to understand the importance of the changes that are induced by
both temperature and time in the magnetic mineralogy and, hence, in the anisotropic
properties of the rock types. Temperature increases are usually the most effective, but
changes that occur as a consequence of the passage of time can be very significant,
yet, being much more subtle, difficult to detect. In general, it is sediments that are
most sensitive to both temperature and the passage of time, reflecting their
ogical changes induced by increasing temperature are likely to be
associated with an increased degree of metamorphism, particularly as the greenschist
˚C, but the migration of hot or cold fluids can
pH conditions, with consequent
modifications of the mineralogy. Such changes will almost always result in a
noticeable modification of the mean susceptibility of the rocks affected, reflecting
erromagnetic minerals, and the mean shape of the
fabric is likely to be drastically altered. These thermochemical effects are most
115
pronounced in sediments in which the mineralogy of the magnetic constituents is
prone to major change. In an extreme case when temperature increases the magnetic
fabrics may even be inverted, as when predominantly single-domain magnetite or
maghaemite grains are produced.
Additionally, the drying out of sediment results not only in chemical changes
due to oxidation but also to the physical realignment of minerals as water menisci
pass through the sample (Noel, 1980).
Weathering marks the peak of readjustment to the environment at the Earth’s
surface. It is primarily a chemical process of oxidation and hydration, but pressure
release can also cause the physical disintegration of a rock. Generally, it is the
chemical changes that are of the most profound importance as these alter both the
composition and grain size of individual minerals. Few studies have been undertaken
specifically to identify the effects of weathering-induced changes on magnetic
anisotropy; usually, however, such effects appear to be disruptive, although there are
situations in which newly formed magnetic minerals pseudomorph the original
paramagnetic grains and thereby enhance the fabric.
5.4 Magnetic Foliation
The Magnetic anisotropy of foliated rocks of several types has been measured
by the torque-meter method, and shows that the alignment of long axes magnetic
grains normally follow the pattern of foliation is evident in field observations. In a
sharp fold in lit-par- lit formation the magnetic anisotropy indicated an otherwise
undetected lineation independent of the bedding and superimposed upon the foliation
determined by the layering.
Magnetic foliations close to the northern and southern margins of the pluton
are similar to the mesoscopic foliations of the surrounding gneisses (Pratheesh et al.,
2013). The orientation of magnetic foliation can also be used to distinguish among
different structures, sills and dykes, a task sometimes impossible simply by field
observations (Halvorsen 1974).
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5.5 Magnetic Lineation
Rock fabrics can reflect the strain state of rocks and are a rich source of
information of tectonic evolution. Lineation is a common fabric element in rocks and
is particularly useful in deciphering the history of deformation. Lineation is
commonly defined as any linear feature that occurs penetratively in a rock and
includes form lineations (crenulation, rods, elongate pebbles) and mineral elongation
(stretched grains, linear aggregates of equidimensional grains, subhedral grains with
an elongate crystal shap, etc.). Lineation introduces anisotropy in the physical
properties of rocks and therefore it can be determined by methods capable of sensing
rock anisotropy.
The most obvious means of determining the origin of magnetic lineation in
deformed rocks is to obtain AMS records from rocks deformed in different tectonic
environments in order to compare the magnetic anisotropy tensor and its axes
distribution with the structural elements (Josep M Pares, et al., 2002).
5.6 Instrument Used
The MFK1 (Multi Function Kappabridge1) Kappabridges are the most
sensitive commercially available laboratory instruments for measuring magnetic
susceptibility and anisotropy of magnetic susceptibility (AMS). The same
Kappabridge is used in the present work of AMS. The Kappabridges have the
following features:
� Automatic zeroing over the entire measuring range.
� High sensitivity
� Automatic compensation of both real and imaginary susceptibility
components.
� Auto-ranging.
� Measuring at three different frequencies (version FA and FB).
� Measuring of in-phase and relative change of out-of-phase component.
� Slowly spinning specimen (version FA and A).
� Quick AMS measurement (FA and A).
� Easy manipulation.
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� Automated field variation measurement (FA and A).
� Only three manual manipulations for measuring AMS (FA and A).
� Built-in circuitry for controlling the furnace CS4 and cryostat CSL
� Full control by computer.
� Sophisticated hardware and software diagnostics.
The Kappabridge apparatus consists of the Pick-Up Unit, Control Unit and
Computer. In principle the instrument represents a precision fully automatic
inductivity bridge. It is equipped with automatic zeroing system and automatic
compensation of the thermal drift of the bridge unbalance as well as automatic
switching appropriate measuring range. The measuring coils at frequency F1 are
designed as 6th-order compensated solenoids with remarkably high field
homogeneity. Special diagnostics was embedded in MFK1 Kappabridges, which
monitors important processes during measurement with MFK1 and also with CS4 or
CSL unit. The MFK1-FB and MFK1-B versions measure the AMS of a static
specimen fixed in the manual holder. In the static method, the same as in KLY-2,
KLY-3 and KLY-4 bridges, the specimen susceptibility is measured in 15 different
orientations following rotatable design. From these values six independent
components of the susceptibility tensor and statistical errors of its determination are
calculated. The specimen positions are changed manually during measurement.
Different component of KLY-2 is showing by arrow in the figure.
5.7 MEASURING OF ANISOTROPY OF MAGNETIC SUSCEPTIBILITY
The measurement of AMS using static specimen method with manual holder
is available with the MFK1-FB or MFK1-B Kappabridges and also with MFK1-FA or
MFK1-A. During measurement process, the susceptibility of the specimen is
measured subsequently in 15 directions following the rotatable Jelinek's design in
exactly the same way as in the KLY-2, KLY-3 and KLY-4 Kappabridges. Using the
least squares method, the susceptibility tensor is fit to these measurements of the 15
directional susceptibilities (Fig. 5.2) and the errors of the fit are calculated.
118
Fig.5.2 MFK1-FA – KLY-2 showing different component.
5.8 Methodology
Sampling procedure in collecting rock samples for AMS is same as used for
paleomagnetic studies (Cox and Doell, 1960; Collinson, 1983; Tarling, 1983; Tarling
and Hrouda, 1993). In both cases oriented block sample collected. Rock sample can
be collected by two ways either drilling in the field itself or oriented block sample
collected for laboratory treatments. Specific size of rock specimen is required for
various measurements because most of the instruments have standard size specimen
holder which are identical for both AMS and paleomagnetic study. However,
magnetic anisotropy is more sensitive to the shape of the specimen than
paleomagnetic. These two methods viz: AMS & palaeomagnetic are most common
standard shape with diameter 2.5 cm and height of 2.1 cm and for cube 2.0 cm side.
Optimum height/ diameter ratio for cylinder can vary between 0 .8 to 0 .9 (Porath et
al., 1966; Noltimier, 1971a; Scriba and Heller, 1978; Collinson, 1983; Tarling and
Hrouda, 1993). In the present study, 20 dyke sites were sampled for AMS study
during the field work, which was held from April - 2009, May - 2010 and November -
2011. In most cases sampling was restrained to middle and lower parts of the flows in
119
order to detect reheating effects and partial alteration of magnetic oxides. Weathered
and jointed rocks are very susceptible for oxidations and hence could have been
affected by remagnetization. Total 200 standard size specimens are measured with the
help of MFK1-FA – KLY-2 for AMS study and there details are given in the Table
5.1. All the measurements have done with pattern of the Jelinek's design of the 15
directions measurements as shown in the Fig. 5.3 given below. The position design is
the same for the cubic and cylindrical specimens.
Fig 5.3 Jelinek's design of the 15 directions measurements of cubic and
cylindrical specimens.
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Table 5.1
Anisotropy of Magnetic Susceptibility Parameters
Sample
No.
of
sam
ples
K1
K2
K3
Kmean
SI Units
K1
K2
K3
Pj
T
L
F
D I D I D I
S1 26 1.003
1 0.996 2.04E-02 340.5 1.1 250 28.2 72.6 61.8 1.025 -0.164 1.014 1.01
RP2 26 1.006
0.998 0.996 1.88E-02 279.8 40.4 164.5 26.7 51.5 37.9 1.039 -0.256 1.025 1.013
JP3 26 1.001
1 0.999 3.75E-03 223.3 3.8 315.5 30 126.7 59.7 1.018 -0.075 1.010 1.007
KG4 25 1.001
1 0.999 1.19E-03 35.3 4 130.4 51.9 302.2 37.9 1.01 -0.053 1.005 1.005
GK5 25 1.003
0.999 0.998 3.16E-03 168.1 77.5 347 12.5 77.1 0.2 1.011 0.161 1.005 1.006
KS6 26 1.001
1.001 0.998 9.18E-04 8.8 12.5 242.4 69.5 102.4 16 1.009 0.287 1.003 1.006
KS7 25 1.001
3 0.999 0.988 1.26E-02 253.5 9.6 348.8 28.7 146.8 59.4 1.057 0.163 1.024 1.031
KS8 25 1.014
1 0.986 1.51E-02 73.3 10.1 168.3 25.9 323.8 61.9 1.073 0.387 1.018 1.05
KRP9 26 1.002
1.001 0.998 1.20E-03 255.5 40.3 9.8 26 122.8 38.7 1.014 0.377 1.004 1.01
IBM10 25 1.002
1 0.998 1.93E-02 102.7 35.1 246.2 48.9 359 18.7 1.025 -0.235 1.015 1.009
NML11 26 1.002
1 0.999 9.65E-04 202.8 44.4 338.8 36.3 87.5 23.6 1.016 0.021 1.008 1.008
MCL12 25 1.001
1 0.999 1.47E-02 355.1 10.2 263.3 9.7 130.7 75.8 1.018 0.004 1.009 1.009
SNG13 26 1.003
1.001 0.996 1.70E-02 110.8 24 266.8 64 16.6 9.4 1.022 -0.076 1.011 1.01
MBN14 26 1.002
1 0.998 2.68E-02 70.4 10.7 329.7 44.7 170.7 43.3 1.21 -0.148 1.011 1.009
KKR15 25 1.003
0.999 0.998 3.80E-03 175.5 51.6 49.8 24.8 306 27.3 1.02 -0.019 1.01 1.009
CPG16 25 1.008
0.999 0.992 8.72E-03 118.1 82.3 353.7 4.4 263.2 6.3 1.031 -0.024 1.016 1.014
NVP17 21 1.001
1 0.999 9.68E-04 166.1 52.5 348.5 37.5 257.2 0.9 1.008 0.004 1.004 1.004
CTL18 25 1.101
0.994 0.905 5.79E-02 166.1 52.5 348 37.5 257 0.9 1.008 0.004 1.004 1.004
EKT19 25 1.002
1 0.998 6.00E-03 62.8 60 332.4 0.2 242.3 30 1.019 0.195 1.008 1.011
K1- Maximum Susceptibility, K2- Intermediate Susceptibility, K3- Minimum Susceptibility, D –
Degrees, I- Degrees, T- Shape Parameter, L – Magnetic Lineation,
F – Magnetic Foliation, Pj – Corrected Degree of Anisotropy,
121
5.9 Analyses of the Anisotropy of Magnetic Susceptibility (AMS) Results
The AMS study of the 20 dykes of the study area specimens revealed the mean
susceptibility values ~1.23 x 10-2 SI Units, indicating the dominance of ferromagnetic
minerals in the studied samples. The degree of anisotropy values are found as 1.033
matching well with the dolerite dykes of other regions of Precambrian terrains.
Whereas another property of anisotropy of magnetic susceptibility lineation and
foliation values are found as 1.003 and 1.25 (Minimum- Maximum) and 1.004 and
1.05 (Minimum- Maximum) respectively showing mostly prolate fabrics.
In most sites of the study magnetic susceptibility is dominantly, shows the
presence of ferromagnetic minerals. Mainly coarse to fine-grained Ti-poor
titanomagnetite up to pure magnetite carry the magnetic fabrics. Three primary AMS
fabrics are recognized in the present work.
Normal AMS fabric (where the greater circle joining K1 and K2 is parallel to
the dyke trend) is dominant in 12 dykes. This fabric is interpreted as a result of
magma flow in which the analysis of Kmax inclination permitted to infer that the
majority of dykes were fed by inclined flows. Intermediate AMS fabric (where the
greater circle joining K1 and K3 is parallel to the dyke trend) was found in 5 dykes.
This type of fabrics is interpreted as due to vertical compaction of a static magma
column with the minimum stress along the dyke strike. Inverse AMS fabric (where
the greater circle joining K2 and K3 is parallel to the dyke trend) is also observed in
the other 2 dykes. This type of fabrics is due to the presence of fine grained
ferromagnetic minerals in the dykes samples. Inclined and horizontal flows allow us
to infer the relative position of at least three magma sources (or magma chambers).
122
S-1 NW-SE
Fig. 5.4: a. Lower hemispheres Stereoplot of AMS data
b. Mean Susceptibility (km) Vs Degree of c. Degree of Anisotropy (Pj) Vs Shape
Anisotropy (Pj) diagram Parameter (T) diagram
Oblate
Prolate
123
RP-2 N-S
Fig. 5.4: a. Lower hemispheres Stereoplot of AMS data
b. Mean Susceptibility (km) Vs Degree of c. Degree of Anisotropy (Pj) Vs Shape
Anisotropy (Pj) diagram Parameter (T) diagram
Oblate
Prolate
124
JP-3 NW-SE
Fig. 5.4: a. Lower hemispheres Stereoplot of AMS data
b. Mean Susceptibility (km) Vs Degree of c. Degree of Anisotropy (Pj) Vs Shape
Anisotropy (Pj) diagram Parameter (T) diagram
Oblate
Prolate
125
KG-4 NNW-SSE
Fig. 5.4: a. Lower hemispheres Stereoplot of AMS data
b. Mean Susceptibility (km) Vs Degree of c. Degree of Anisotropy (Pj) Vs Shape
Anisotropy (Pj) diagram Parameter (T) diagram
Oblate
Prolate
126
GK-5 NE-SW
Fig. 5.4: a. Lower hemispheres Stereoplot of AMS data
b. Mean Susceptibility (km) Vs Degree of c. Degree of Anisotropy (Pj) Vs Shape
Anisotropy (Pj) diagram Parameter (T) diagram
Oblate
Prolate
127
KS-6 NE-SW
Fig. 5.4: a. Lower hemispheres stereoplot of AMS data
b. Mean Susceptibility (km) Vs Degree of c. Degree of Anisotropy (Pj) Vs Shape
Anisotropy (Pj) diagram Parameter (T) diagram
Oblate
Prolate
Oe
128
KS-7 NE-SW
Fig. 5.4: a. Lower hemispheres stereoplot of AMS data
b. Mean Susceptibility (km) Vs Degree of c. Degree of Anisotropy (Pj) Vs Shape
Anisotropy (Pj) diagram Parameter (T) diagram
Oblate
Prolate
129
KS-8 NE-SW
Fig. 5.4: a.Lower hemispheres stereoplot of AMS data
b. Mean Susceptibility (km) Vs Degree of c. Degree of Anisotropy (Pj) Vs Shape
Anisotropy (Pj) diagram Parameter (T) diagram
Oblate
Prolate
ate
130
KRP-9 NNE-SSW
Fig. 5.4: a.Lower hemispheres stereoplot of AMS data
b. Mean Susceptibility (km) Vs Degree of c. Degree of Anisotropy (Pj) Vs Shape
Anisotropy (Pj) diagram Parameter (T) diagram
Oblate
Prolate
131
IBM 10 E-W
Fig. 5.4: a. Lower hemispheres stereoplot of AMS data
b. Mean Susceptibility (km) Vs Degree of c. Degree of Anisotropy (Pj) Vs Shape
Anisotropy (Pj) diagram Parameter (T) diagram
Oblate
Prolate
132
NML-11 N-S
Fig. 5.4: a. Lower hemispheres stereoplot of AMS data
b. Mean Susceptibility (km) Vs Degree of c. Degree of Anisotropy (Pj) Vs Shape
Anisotropy (Pj) diagram Parameter (T) diagram
Oblate
Prolate
133
MCL-12 NW-SE
Fig. 5.4: a. Lower hemispheres stereoplot of AMS data
b. Mean Susceptibility (km) Vs Degree of c. Degree of Anisotropy (Pj) Vs Shape
Anisotropy (Pj) diagram Parameter (T) diagram
Oblate
Prolate
134
SNG-13 E-W
Fig. 5.4: a. Lower hemispheres stereoplot of AMS data
b. Mean Susceptibility (km) Vs Degree of c. Degree of Anisotropy (Pj) Vs Shape
Anisotropy (Pj) diagram Parameter (T) diagram
Oblate
Prolate
135
MBN-14 NE-SW (ENE-WSW)
Fig. 5.4: a. Lower hemispheres stereoplot of AMS data
b. Mean Susceptibility (km) Vs Degree of c. Degree of Anisotropy (Pj) Vs Shape
Anisotropy (Pj) diagram Parameter (T) diagram
Oblate
Prolate
e
136
KKR-15 E-W
Fig. 5.4: a. Lower hemispheres stereoplot of AMS data
b. Mean Susceptibility (km) Vs Degree of c. Degree of Anisotropy (Pj) Vs Shape
Anisotropy (Pj) diagram Parameter (T) diagram
Oblate
Prolate
137
CPG-16 NE-SW
Fig. 5.4: a. Lower hemispheres stereoplot of AMS data
b. Mean Susceptibility (km) Vs Degree of c. Degree of Anisotropy (Pj) Vs Shape
Anisotropy (Pj) diagram Parameter (T) diagram
Oblate
Prolate
138
NVP-17 NW-SE
Fig. 5.4: a. Lower hemispheres stereoplot of AMS data
b. Mean Susceptibility (km) Vs Degree of c. Degree of Anisotropy (Pj) Vs Shape
Anisotropy (Pj) diagram Parameter (T) diagram
Oblate
Prolate
139
CTL-18 NE-SW
Fig. 5.4: a. Lower hemispheres stereoplot of AMS data
b. Mean Susceptibility (km) Vs Degree of c. Degree of Anisotropy (Pj) Vs Shape
Anisotropy (Pj) diagram Parameter (T) diagram
Oblate
Prolate
e
140
EKT-19 NE-SW
Fig. 5.4: a. Lower hemispheres stereoplot of AMS data
b. Mean Susceptibility (km) Vs Degree of c. Degree of Anisotropy (Pj) Vs Shape
Anisotropy (Pj) diagram Parameter (T) diagram
Oblate
Prolate
141
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