www.elsevier.com/locate/ijcoalgeo

International Journal of Coal Geology 54 (2003) 57–68

Pliocene lignites from Apofysis mine, Amynteo basin,

Northwestern Greece: petrographical characteristics and

depositional environment

A. Iordanidis*, A. Georgakopoulos

Department of Mineralogy-Petrology-Economic Geology, School of Geology, Aristotle University of Thessaloniki,

GR-54006 Thessaloniki, Greece

Abstract

Coal petrological investigation along with proximate and elemental analyses were undertaken to determine the

petrographic characteristics of the Apofysis lignites (Amynteo basin, Northwestern Greece) and their depositional

environment. Eight samples (representing different lignite beds of the Apofysis deposit) were collected from a borehole.

The Apofysis lignites have an Eu-ulminite B reflectance of Rr = 0.22%, and in terms of lithotype belong to matrix soft

brown coals. Huminite is the most abundant maceral group and consists mostly of humodetrinite. Inertinite has relatively

low percentages whereas liptinite concentrations are low in the lower lignite beds and higher in the upper ones. Ternary

plots and facies indices were employed in order to investigate the palaeoenvironment. The depositional environment of the

Apofysis lignites is not definitely ascribed to a forest swamp or a reed marsh environment. The high ash content of the

analysed samples is a clear indication of a topogenous setting. Low tissue preservation index (TPI) and high gelification

index (GI) values are observed. High alkalinity and strongly reducing conditions may be inferred from the presence of

syngenetic (framboidal) pyrite, the low TPI values which indicate high bacterial activity, and thus high pH conditions, and

the preservation of gastropod shells and chlorophyllinite. High GI indicates a constant influx of calcium-rich waters into

the coal swamp. The Apofysis lignite deposit may be interpreted to be autochthonous to hypoautochthonous. The peat

accumulation was governed by a high groundwater level (wet telmatic to limno-telmatic facies) and a moderate subsidence

rate.

D 2003 Elsevier Science B.V. All rights reserved.

Keywords: Coal petrology; Depositional environment; Lignites; Amynteo; Ptolemais; Greece

1. Introduction

Most Greek lignite deposits are located in the

Florina–Ptolemais–Kozani basin, a large inten-

0166-5162/03/$ - see front matter D 2003 Elsevier Science B.V. All right

doi:10.1016/S0166-5162(03)00019-3

* Corresponding author. Tel.: +30-31-998-459; fax: +30-31-

998-568.

E-mail address: aiordanidis@yahoo.co.uk (A. Iordanidis).

sively exploited area, in Northern Greece. This area

is exploited by opencast mining and feeds nearby

lignite-fired power stations. The contribution of

lignite to the total electric power output of the

country exceeds 75%. Several studies have been

published on the petrography of Greek lignites, but

few works have been carried out for the Ptolemais

area (Cameron et al., 1984; Kaouras, 1989; Fowler

et al., 1991; Antoniadis, 1992; Antoniadis et al.,

s reserved.

A. Iordanidis, A. Georgakopoulos / International Journal of Coal Geology 54 (2003) 57–6858

1994; Valceva et al., 1995; Antoniadis and Lamp-

ropoulou, 1995; Antoniadis and Rieber, 1997;

Kalaitzidis et al., 1998, 2000; Georgakopoulos and

Fig. 1. Simplified geological map of the Florina–Ptolemais–Koza

Valceva, 2000). In particular, no detailed and sys-

tematic coal petrographic investigations have been

carried out for the Amynteo area. The present work

ni basin, showing the location of the Apofysis lignite mine.

A. Iordanidis, A. Georgakopoulos / International Journal of Coal Geology 54 (2003) 57–68 59

aims to study the vertical differentiation in petro-

graphic characteristics of Apofysis lignites and

make a broad estimation of the depositional envi-

ronment.

2. Geologic setting

The elongated intermontaine Florina–Ptolemais–

Kozani basin is a NNW–SSE trending graben

system that extends over a distance of 250 km

from Bitola, in the Former Yugoslavian Republic of

Macedonia to Servia, southeast of Kozani, Greece.

The basement consists of metamorphic schists in

the west and crystalline limestone in the east. The

Amynteo basin is part of this graben that opened in

the late Miocene and was divided into sub-basins in

the Pleistocene (Pavlides and Mountrakis, 1986).

The Apofysis opencast lignite mine is situated 700

m above sea level at the southwestern margins of

the Amynteo coal-bearing basin and covers a sur-

face area of 4.4 km2 (Fig. 1). The Apofysis

deposits consist of rythmic alterations of lignite

beds and lacustrine and fluvial sediments (Koukou-

zas et al., 1981).

Fig. 2. Simplified stratigraphic column of the drilled section of the

Apofysis lignite deposit, showing the sampling intervals.

3. Sampling and analytical methods

Eight lignite samples were collected from a

borehole located in the central part of the Apofysis

mine. Since the Apofysis deposit is a complex

succession of lignite beds and interbedded clastic

materials, only lignite beds thicker than 50 cm were

chosen for sampling. Lignite beds are located in the

depth interval between 50 and 100 m. A simplified

stratigraphic column of the Apofysis lignite deposit

showing the sampling intervals is shown in Fig. 2.

The depth of sampling is also shown in Table 1.

For proximate and ultimate analysis an aliquot of

each sample was ground to < 100 mesh and

analysed following the procedures outlined by

DIN (Deutsches Institut fur Normung-DIN, 1995,

1978). Sulphur was determined using a LECO SC-

144DR analyzer. Carbon, hydrogen and nitrogen

were determined using a LECO CHN-2000 ana-

lyzer. Total organic carbon (TOC) was analyzed

using a LECO CR-12 carbon determinator. Pol-

ished blocks were prepared for maceral analysis

and Eu-ulminite B reflectance measurements (ran-

dom). At least 300 points were counted in

reflected white light in order to determine the

content of huminite and inertinite macerals, as well

as the mineral matter and pyrite contents. For the

determination of liptinite maceral content, the

count was repeated in fluorescence mode. The

combination of the two modes gave a complete

maceral analysis based on a total of more than

600 points. Maceral subgroups were determined for

the huminite group. The samples were also macro-

scopically described according to the classification

Table 1

Proximate and ultimate analyses of Apofysis lignite samples, as well as lithotype determination

Sample

ID

Depth

(m)

Moisture

(ad) %

Ash

(ad) %

Ash

(db) %

C

(daf) %

H

(daf) %

N

(daf) %

O

(daf) %

S

(daf) %

S +O

(daf) %

Lithotypes

A129 58.9 16.1 9.3 11.1 57.6 4.6 0.8 34.2 2.8 37.0 stratified-brown

A139 64.3 22.5 39.2 50.6 41.9 3.5 1.3 50.8 2.5 53.3 friable-unstratified-

brown

A144 67 22.1 24.3 31.2 55.0 5.4 1.6 nd nd 38.0 stratified-brown

A152 71 17.8 15.2 18.5 57.3 4.6 1.5 nd nd 36.6 stratified-black

A158 75 23.7 21.2 27.8 58.6 4.1 1.9 32.7 2.7 35.4 unstratified-black

A167 82.6 22.3 11.6 14.9 58.9 5.0 1.5 nd nd 34.6 stratified-black

A171 85 18.9 31.4 38.7 54.1 4.4 1.9 37.9 1.7 39.7 stratified-brown

A173 87 15.9 22.5 26.8 66.8 3.1 2.1 nd nd 28.0 stratified-black

nd = not determined; ad = air-dried basis; db = dry basis; daf = dry ash-free basis.

A. Iordanidis, A. Georgakopoulos / International Journal of Coal Geology 54 (2003) 57–6860

system for lithotypes of soft brown coals adopted

by ICCP (1993).

4. Results and discussion

The moisture, ash and total sulphur contents

together with the results of ultimate analysis are

summarized in Table 1. TOC measurements and

maceral composition along with mineral matter and

pyrite contents are shown in Table 2. Random

vitrinite reflectance measurements on Eu-ulminite B

in two samples (a total of 100 counts) gave a mean

value of 0.22% (F 0.02) Rrandom in both samples, a

value that suggests a transition from peat to lignite.

TOC ranges from 63.8% up to 71.0% (daf). Carbon

ranges from 41.9% to 66.8% (daf), hydrogen from

3.1% up to 5.4% (daf) and nitrogen from 0.8% to

2.1% (daf).

According to the terminology and descriptions

recommended by the International Committee for

Coal and Organic Petrology (ICCP, 1993), the Apof-

ysis lignites belong to matrix coal with an obvious

vertical differentiation in colour and stratification, as

shown in Table 1. Brown (weakly gelified) and

brownish black (more strongly gelified) coal litho-

types are consistent through out the lithostratigraphic

section. The dark, more gelified coal may be the

product of anaerobic processes, while the pale coal,

generally formed by strong decay, may reveal more

or less aerobic conditions. However, according to

Hagemann and Wolf (1987), the light and dark

lignite bands result mainly from different degrees

of plant decompositions.

Huminite is the most abundant maceral group

(71.9–90.8 vol.%, mmf) and consists mostly of

humodetrinite [except sample A173 where humocol-

linite (Fig. 3a and b) is more abundant and sample

A167 where humotelinite is more abundant], while

inertinite has relatively low percentages (up to 14

vol.%, mmf) and liptinite shows low contents in the

lower lignite beds but higher concentrations (up to

25.7 vol.%, mmf) in the upper lignite beds. Character-

istic maceral types are shown in microphotographs of

Apofysis lignites in Figs. 3 and 4. The relative

abundance of maceral groups and mineral matter is

represented in ternary plots (Fig. 5). Although mac-

erals of the humodetrinite subgroup (i.e. attrinite and

densinite) are not analysed separately, it is observed

that both macerals contribute equally to the maceral

composition of the studied coals (Fig. 3c–e). Genesis

of humodetrinite may be attributed to relatively aero-

bic conditions (Teichmuller et al., 1998b). The Apof-

ysis mine is situated at the margins of the Amynteo

coal-bearing basin (i.e. at the margins of the precursor

peat mires), and at the margin of a peat bed, there is

greater prevalence of the physical breakdown of peat

to particulate matrix (Kuder et al., 1998), thus the

prevalence of humodetrinite. Attrinite and densinite

are also the principal constituents of peats and brown

coals from treeless marshes. It is considered that

‘coniferous-forest coals’ display better preservation

and larger sizes of cellular tissues (humotelinites) than

the ‘angiosperm-forest coals’, and also that reed peats

and reed brown coals (i.e. deposits of poorly lignified

and relatively cellulose-rich plants) consist mainly of

humodetrinite (Cameron et al., 1984; Teichmuller et

al., 1998b). However, the general assumption that

Table

2

Totalorganic

carbon(TOC)contents(w

t.%),maceral

andmineral

mattercontents(vol.%)andcalculatedfacies

indices

oflignitesamplesfrom

theApofysismine

Sam

ple

TOC

Huminitevol.%

(mmf)

Inertinitevol.%

(mmf)

Liptinitevol.%

(mmf)

Mineral

matter

Faciesindices

ID(daf)

%Htel

Hdet

Hcol

SHum

Fus

Sfus

Idet

Scle

SIner

Cut

Spor

Fluo

Res

Chlo

Lipd

Sub

SLip

MM

Pyr

TPI

GI

GWI

VI

A129

66.4

34.7

47.1

0.0

81.7

0.0

0.0

6.6

0.0

6.6

4.4

0.2

0.6

0.0

0.2

6.2

0.0

11.7

18.8

3.5

0.6

12.4

1.9

0.5

A139

63.8

10.3

60.8

0.8

71.9

1.6

0.0

0.8

0.0

2.4

8.0

0.4

2.5

4.2

1.7

8.9

0.0

25.7

52.6

2.3

0.2

30.2

11.1

0.2

A144

67.0

29.2

44.9

6.8

80.8

2.1

0.4

2.1

0.0

4.5

6.2

1.1

3.7

0.5

0.0

3.0

0.2

14.6

12.4

2.8

0.6

17.8

2.2

0.5

A152

68.4

7.8

65.5

4.6

77.9

4.3

0.5

1.6

0.0

6.5

2.3

1.2

2.6

0.9

0.3

8.4

0.0

15.6

30.8

2.7

0.2

12.0

12.9

0.2

A158

71.0

23.9

45.8

5.2

75.0

3.6

1.6

6.2

0.3

11.8

4.8

1.0

2.7

0.3

0.0

4.4

0.0

13.3

41.2

2.2

0.5

6.4

3.9

0.5

A167

70.3

64.5

19.5

6.5

90.6

1.1

0.0

1.1

0.0

2.2

1.1

1.7

0.6

2.8

0.0

1.1

0.0

7.3

10.7

2.8

2.4

41.8

0.6

2.7

A171

65.8

4.9

71.3

5.6

81.8

7.0

0.7

6.3

0.0

14.0

0.0

0.0

0.0

2.1

0.0

1.4

0.7

4.2

29.1

1.5

0.2

5.9

21.7

0.2

A173

68.5

32.0

19.2

39.5

90.8

1.1

0.0

1.6

0.0

2.7

3.8

1.6

0.0

1.1

0.0

0.0

0.0

6.6

8.4

3.3

0.5

34.0

2.1

1.3

daf=dry-ash

free;mmf=mineral

matterfree

basis;Htel=

humotelinite;

Hdet=humodetrinite;

Hcol=

humocollinite;

SHum=totalhuminite;

Fus=fusinite;

Sfus=Sem

ifusinite;

Idet=inertodetrinite;

Siner=totalinertinite;

Cut=

cutinite;

Spor=sporinite;

Fluo=fluorinite;

Res=resinite;

Chlo=chlorophyllinite;

Lipd=liptodetrinite;

Sub=suberinite;

SLip=totalliptinite;

MM

=mineral

matterother

than

pyrite;Pyr=pyrite;TPI=tissue

preservation

index;GI=gelification

index;GWI=groundwater

influence

index;

VI=vegetationindex.

A. Iordanidis, A. Georgakopoulos / International Journal of Coal Geology 54 (2003) 57–68 61

herbaceous/reed/and other monocotyledonen peats

give a high proportion of unstructured macerals

(humodetrinite) due to their lower lignin content is

not necessarily true. In addition, the general assump-

tion that gymnosperms are more resistant to decom-

position than woody angiosperms, which in turn are

more resistant than herbaceous angiosperm material,

may also be misleading (Dehmer, 1995). A wet forest

swamp may give rise to peats with a petrographic

composition similar to marsh peats if the depositional

conditions favour microbial destruction of the cellular

structure (Diessel, 1992). The best preserved tissues

are the deeper roots (Fig. 3f) that were protected from

aerial oxidation and reached below the peatigenic

layer.

In calcium-rich coals, neutral to alkaline deposi-

tional environments allow bacteria to cause severe

structural decomposition, leading to the formation of

humic gels and peatification products relatively rich in

nitrogen and hydrogen (Teichmuller et al., 1998a).

That is true for sample A173, which has the highest

humocollinite and nitrogen contents, although the

hydrogen content is rather low. The surrounding and

basement rocks of the Amynteo basin consist mainly

of crystalline limestones, which are supposed to be the

sources of calcium. A high content of eugelinite is

also characteristic of the calcium-rich brown coals

(see Fig. 3g). The presence of chlorophyllinite in the

upper lignite beds suggests wet and alkaline reducing

conditions (Cabrera et al., 1995; Dehmer, 1995;

Querol et al., 1996). A high content of calcium leads

to a high degree of bacterial degradation of the plant

remains and to bacterial reduction of sulphates, result-

ing in coals with high amounts of collinite and pyrite

(e.g. sample A173).

The pyrite content is relatively high (1.5–3.5

vol.%), in discordance with the presumed terrestrial

origin of the Apofysis lignites. Pyrite is found mostly

in the form of framboidal pyrite (Fig. 3h) and suggests

enhanced activity of sulphate-reducing bacteria, prob-

ably related to carbonate and sulphate-rich waters in

the basin during peat formation (Kuder et al., 1998;

Teichmuller et al., 1998a). Pyrite thus indicates a

marine influence and suggests that the Amynteo basin

was not totally isolated from the marine environment

during peat accumulation. Iron sulphide in peats can

be formed only through bacterial activity, since there

is insufficient energy for a purely chemical reduction

Fig. 3. Microphotographs of macerals in the Apofysis lignites: (a) phlobaphinite (ph) and suberinite (sub); (b) same field as (a) under blue light

irradiation; (c) humotelinite (ht) and humodetrinite (hd); (d) fusinite (fus), humodetrinite (hd) and humotelinite (ht); (e) humotelinite (htel),

humodetrinite (hdet) and corpohuminite (crph); (f) cross section of rootlet; (g) humotelinite (htel) and gelinite (gel); (h) framboidal pyrite. All

microphotographs were taken under reflected white light and oil immersion, except (b) and (f), which were taken under fluorescence-inducing

blue light.

A. Iordanidis, A. Georgakopoulos / International Journal of Coal Geology 54 (2003) 57–6862

Fig. 4. Microphotographs of macerals in the Apofysis lignites: (a) clay minerals and humodetrinite matrix; (b) porigelinite (por) intruded into

cell lumens; (c) Bogen structure of fusinite; (d) megaspore; (e) suberinite (sub) cell walls of a cortex; (f) compacted sporinite; (g) cutinite; (h)

megaspore. All photomicrographs were taken under fluorescence-inducing blue light and oil immersion, except (a), (b) and (c), which were

taken under reflected white light.

A. Iordanidis, A. Georgakopoulos / International Journal of Coal Geology 54 (2003) 57–68 63

Fig. 5. Ternary plots of (a) huminite, (inertinite + liptinite) and mineral matter contents and (b) of huminite, inertinite and liptinite contents (mmf).

A. Iordanidis, A. Georgakopoulos / International Journal of Coal Geology 54 (2003) 57–6864

of sulphates to sulphides (Neavel, 1966). The iron

probably enters the swamp adsorbed on clays.

Because of this, pyrite is commonly found adjacent

to clay-rich zones (Cabrera et al., 1995). Though it is

difficult to recognize minerals in humodetrinite-rich

coals (Markic and Sachsenhofer, 1997), clays were

determined in this study as the main constituents of

the mineral matter (Fig. 4a and b).

Under aerobic degradation, the most resistant com-

ponents, like liptinite and mineral matter, are rela-

tively enriched, and increased amounts of the liptinite

group macerals may therefore indicate higher levels of

degradation in the peat swamp (Cabrera et al., 1995;

Rimmer et al., 2000). The high liptinite content of the

A139 sample corroborates the fact that the amount of

liptinite is generally high in coals with high mineral

matter content. The liptinite in this study consists

mostly of resinite and cutinite, macerals that are very

resistant to degradation and thus may preferentially be

preserved. The enrichment of liptinite macerals, such

as sporinite (Fig. 4d,f,h), cutinite (Fig. 4g) and resinite

as well as dispersed fragments of fusinite and semi-

fusinite in the form of inertodetrinite, in most of the

coal samples support the hypothesis that the peat was

subjected to severe humification (Ligouis et al., 1998).

Waxes are associated with a number of macerals,

especially cutinite and suberinite. A more temperate

climate with gymnosperm flora may also be inferred

from the presence of waxes and cutines, as also

suggested from palynological data from the nearby

Ptolemais basin (Singh and Singh, 2000; van Hoeve,

2000).

Ternary diagrams of specific maceral assemblages

are used for the evaluation of depositional conditions.

The depositional environment of the Apofysis lig-

nites, as shown in a ternary plot (Fig. 6), is not

definitely ascribed to forest swamp or a reed marsh

environment. These ternary plots are indicators only

and should be used complementary to palaeobotany

and palynology in order to determine the coal-forming

environments (DiMichele et al., 1987; Shearer and

Moore, 1994).

Diessel (1986) has introduced two petrographic

indices, i.e. the gelification index (GI) and tissue

preservation index (TPI). These indices were used to

characterize the depositional environments of Austral-

ian Permian coals. For low rank Miocene and Jurassic

coals, these indices have been modified by Kalkreuth

et al. (1991) and Petersen (1993), respectively. On the

basis of some criteria used in the classification of

modern peatlands, Calder et al. (1991) introduced the

groundwater influence index (GWI) and the vegeta-

tion index (VI) to characterize paleomires. In the

present study the formulas proposed by Georgako-

Fig. 6. Ternary plot showing suggested peat-forming environments for the Apofysis lignites, based on maceral assemblages (modified from

Kalkreuth et al., 1996).

inite

A. Iordanidis, A. Georgakopoulos / International Journal of Coal Geology 54 (2003) 57–68 65

poulos and Valceva (2000) for TPI, VI and GWI and

by Petersen (1993) for GI have been adapted. The

formulae are:

TPI ¼ humoteliniteþ semifusiniteþ fusinite

humodetriniteþ humocollinite þ inertodetr

VI ¼ humoteliniteþ fusinite þ semifusinite þ scle

humodetriniteþ inertodetriniteþ liptodetriniteþ

GWI ¼ humodetriniteþ humocolliniteþ clay minerals

humotelinite

;

TPI is mainly governed by water depth and the

frequency of dry periods and is modified by pH and

trophic level, but the botanical composition plays also

GI ¼ huminite

inertinite

rotinite þ suberiniteþ resinite

sporiniteþ cutiniteþ fluorinite

a role. Low TPI values, for example, can be either the

result of the vegetation type (e.g. high angiosperm/

gymnosperm ratio) or due to less favourable condi-

tions of tissue preservation (Kolcon and Sachsenhofer,

1999). GI is a measure of groundwater table and/or

pH indicator, because gelification requires the contin-

uous presence of water and because microbial activity

requires low acidity (Kolcon and Sachsenhofer,

1999). A fluctuating water table caused by drier

periods may increase the wildfire frequency, which

also will influence the GI due to the formation of

inertinite during burning of the plants. These facies

indices should be treated with caution, since palae-

obotanical and/or palynological data are needed in

A. Iordanidis, A. Georgakopoulos / International Journal of Coal Geology 54 (2003) 57–6866

order to have a more accurate description of the

palaeoenvironment (Calder, 1993; Collinson and

Scott, 1987; Crosdale, 1993).

The calculated values of TPI, GI, GWI and VI are

shown in Table 2. TPI values resemble VI values

except for sample A173, probably due to its high

humocollinite content. TPI versus GI and GWI versus

VI diagrams have also been used in order to determine

the depositional environments (Fig. 7). Low TPI and

high GI values are observed (Fig. 7a). TPI values less

than 0.5 and GI values higher than 6 suggest a

topogenous mire. The calculated values of GWI>1

and VI < 1 (Fig. 7b) suggest a rheotrophic site (limno-

telmatic or even inundated stage). GI>10 suggests a

marsh-reed environment or a forest with high degrees

of degradation, permanently flooded. These values

suggest either a limno-telmatic swamp with low sub-

sidence combined with a slow fall in the groundwater

table or a treeless, open marsh area with major

contributions from open marsh and limnic plant

communities. It is very difficult to separate telmatic

and limnic conditions, because subaquatic (limnic)

sedimentation also takes place in forest swamps and

particularly in reed swamps (Singh and Singh, 2000).

There is numerous evidence that support the first

hypothesis (i.e. limno-telmatic swamp). The high

pyrite content suggests enhanced bacterial activity,

which in turn destroys cellular structure and thus the

poor tissue preservation. The gastropods found in

lignites and intercalated marls from lower sections

reveal an alkaline environment and flooding events

(Inci, 1998; Markic and Sachsenhofer, 1997). An

Fig. 7. Plots of (a) gelification index (GI) versus tissue preservation index

index (VI) (modified from Diessel, 1986; Calder et al., 1991).

alkaline, calcerous non-marine environments is also

suggested by the abundance of humocollinite in the

lower lignite beds, as well as the high GI values

indicate a constant influx of calcium-rich waters into

the coal swamp (Markic and Sachsenhofer, 1997;

Singh and Singh, 2000). The negative correlation

between TPI and ash for the Apofysis lignites indicates

that intense clastic sedimentation reduced the tree

density and/or produced unfavourable conditions for

tissue preservation (Markic and Sachsenhofer, 1997).

In summary, it can be concluded that the Apof-

ysis deposit was autochthonous to hypoautochtho-

nous. The peat accumulation was governed by a

high groundwater level (wet telmatic to limno-tel-

matic facies) and a moderate subsidence rate. High

alkalinity, reducing conditions and marine influence

may be inferred from the presence of syngenetic

(framboidal) pyrite. The low TPI values indicate

high bacterial activity, and thus high pH conditions,

and the preservation of gastropod shells and chlor-

ophyllinite support an alkaline environment (Querol

et al., 1996).

5. Conclusions

The Apofysis lignites have an Eu-ulminite B reflec-

tance of 0.22% Rr and the investigated samples belong

to the lithotype category of matrix soft brown coals.

Huminite is the most abundant maceral group and

consists mostly of humodetrinite, whereas inertinite

has relatively low percentages and liptinite shows low

(TPI) and (b) groundwater influence index (GWI) versus vegetation

A. Iordanidis, A. Georgakopoulos / International Journal of Coal Geology 54 (2003) 57–68 67

contents in the lower lignite beds and higher (up to

25.7 vol.%, mmf) in the upper lignite sections. Pyrite

content is relatively high (1.5–3.5 vol.%) in the

Apofysis lignites. Pyrite is found mostly in the form

of framboidal pyrite and suggests enhanced activity of

sulphate-reducing bacteria, probably related to carbo-

nate and sulphate-rich waters in the basin. The pres-

ence of high amounts of pyrites thus indicates a marine

influence on the precursor mires.

Low TPI and high GI values are observed. TPI less

than 0.5 and GI higher than 6 suggest a topogenous

mire. GWI>1 and VI < 1 suggest a rheotrophic site

(limno-telmatic or even inundated stage). GI>10

reveals a marsh-reed environment or a forest with

high degrees of degradation, permanently flooded.

The depositional environment of the Apofysis lignites

is not definitely ascribed to forest swamp or a reed

marsh environment. The high ash content of the

investigated samples is a clear indication of a top-

ogenous setting. High alkalinity and reducing condi-

tions may be inferred from the presence of syngenetic

(framboidal) pyrite, the low TPI values which indicate

high bacterial activity, and thus high pH conditions,

and the preservation of gastropod shells and chloro-

phyllinite. Thus, the Apofysis lignite deposit may be

interpreted as autochthonous to hypoautochthonous.

The peat accumulation was governed by a high

groundwater level (wet telmatic to limno-telmatic

facies) and a moderate subsidence rate.

All facies indices should be treated with caution,

since several authors have included or excluded

specific maceral types in their calculations, depending

on the rank and specific petrographic features of the

studied coals, which might result in misleading con-

clusions. Because of these ambiguities, petrographic

indices should be used together with independent

information, like palaeobotany and/or palynology in

order to give an integrated picture of the character-

istics of the depositional environment.

Acknowledgements

Financial support from Deutscher Akademischer

Austauschdienst (DAAD), through a short-term

research scholarship awarded to A. Iordanidis, is

gratefully acknowledged. The analytical work was

conducted at the Institute of Geology and Geo-

chemistry of Petroleum and Coal, RWTH-Aachen,

Germany. Professor Ralf Littke and scientific staff of

the former Institute are personally thanked. The help

of employees of the Public Power Corporation of

Greece during sampling is deeply appreciated. We are

also most thankful to W. Kalkreuth, T.A. Moore and

H.I. Petersen for their constructive review.

References

Antoniadis, P.A., 1992. Uber das Lignitvorkommen von Lava

(Kozani): Struktur, Bau und Palaogeographie nach Sedimento-

logischen Aspekten. Min. Metall. Ann., Athens 2, 87–106.

Antoniadis, P.A., Lampropoulou, E., 1995. Depositional environ-

ment interpretations based on coal facies analysis of Lava’s

lignite deposit (Greece). Doc. Nat. 96, 1–12.

Antoniadis, P.A., Rieber, E., 1997. Zu Fossilinhalt, Kohlegenese

und Stratigraphie des Kohlebeckens von Lava in Nord Grie-

chenland. Acta Palaeobot. 37 (1), 61–80.

Antoniadis, P.A., Blickwede, H., Kaouras, G., 1994. Polleninhalt

und petrographischer Aufbau des Flozabschnittes (36,0–51,0 m)

eine Tiefbohrung der obermiozanen Braunkohle von Lava bei

Kozani NW-Griechenland. Miner. Wealth, Athens 9, 7–17.

Cabrera, L., Hagemann, H.W., Pickel, W., Saez, A., 1995. The coal-

bearing, Cenozoic As Pontes Basin (northwestern Spain): geo-

logical influence on coal characteristics. Int. J. Coal Geol. 27,

201–226.

Calder, J.H., 1993. The evolution of a ground-water influenced

(Westphalian B) peat-forming ecosystem in a piedmont setting:

the No. 3 seam, Springhill coalfield, Cumberland Basin, Nova

Scotia. In: Cobb, J.C., Cecil, C.B. (Eds.), Modern and Ancient

Coal-Forming Environments. Geol. Soc. Am. Spec. Paper,

Boulder, CO, pp. 153–180.

Calder, J.H., Gibling, M.R., Mukhopadhyay, P.K., 1991. Peat for-

mation in a Westphalian B piedmont setting, Cumberland basin,

Nova Scotia: implications for the maceral-based interpretation

of rheotrophic and raised paleomires. Bull. Soc. Geol. Fr. 162,

283–298.

Cameron, A.R., Kalkreuth, W.D., Koukouzas, C.N., 1984. The pet-

rology of Greek brown coals. Int. J. Coal Geol. 4, 173–207.

Collinson, M.E., Scott, A.C., 1987. Implications of vegetational

change through the geological record on models of coal-forming

environments. In: Scott, A.C. (Ed.), Coal and Coal-Bearing

Strata: Recent Advances. Geol. Soc. Am. Spec. Paper, Boulder,

CO, pp. 67–85.

Crosdale, P.J., 1993. Coal maceral ratios as indicators of environ-

ment of deposition: do they work for ombrogenous mires? An

example from the Miocene of New Zealand. Org. Geochem. 20

(6), 797–809.

Dehmer, J., 1995. Petrological and organic geochemical investi-

gation of recent peats with known environments of deposition.

Int. J. Coal Geol. 28, 111–138.

Deutsches Institut fur Normung-DIN 51718, 1995. Testing of solid

fuels—determination of the water content and the moisture of

analysis sample.

A. Iordanidis, A. Georgakopoulos / International Journal of Coal Geology 54 (2003) 57–6868

Deutsches Institut fur Normung-DIN 51719, 1978. Testing of solid

fuels—determination of ash content.

Diessel, C.F.K., 1986. On the correlation between coal facies and

depositional environments. Advances in the Study of the Syd-

ney Basin, Proc. 20th Symposium, University of Newcastle,

Australia, pp. 19–22.

Diessel, C.F.K., 1992. Coal-Bearing Depositional Systems. Spring-

er-Verlag, Berlin. 721 pp.

DiMichele, W.A., Phillips, T.L., Olmstead, R.G., 1987. Opportun-

istic evolution: abiotic environmental stress and the fossil record

of plants. Rev. Palaeobot. Palynol. 151, 151–178.

Fowler, M.G., Gentzis, T., Goodarzi, F., Foscolos, A.E., 1991. The

petroleum potential of some Tertiary lignites from Northern

Greece as determined using pyrolysis and organic petrological

techniques. Org. Geochem. 17, 805–826.

Georgakopoulos, A., Valceva, S., 2000. Petrographic characteristics

of Neogene Lignites from the Ptolemais and Servia basins,

Northern Greece. Energy Sources 22, 587–602.

Hagemann, H.W., Wolf, M., 1987. New interpretations of the facies

of the Rhenish brown coal of West Germany. Int. J. Coal Geol.

7, 337–348.

Inci, U., 1998. Lignite and carbonate deposition in middle Lignite

succession of the Soma formation, Soma coalfield, Western

Turkey. Int. J. Coal Geol. 37, 287–313.

International Committee for Coal and Organic Petrology (ICCP),

1993. International Handbook of Coal Petrography, 2nd ed., 3rd

Suppl. University of Newcastle upon Tyne, England.

Kalaitzidis, S., Bouzinos, A., Christanis, K., 1998. The depositional

palaeoenvironment of the Upper Xylitic Horizon of the Ptole-

mais lignite deposit (in Greek). Proc. 8th Int. Congress Geol.

Soc. Greece (Patras, 27–29.5.1998). Bull. Geol. Soc. Greece,

vol. XXXII/2, pp. 289–297.

Kalaitzidis, S., Bouzinos, A., Christanis, K., 2000. The lignite-

forming palaeoenvironment before and after the volcanic tephra

deposition in the Ptolemais basin, Hellas (in Greek). Miner.

Wealth, Athens 115, 29–42.

Kalkreuth, W., Kotis, T., Papanicolaou, C., Kokkinakis, P., 1991.

The geology and coal petrology of a Miocene lignite profile at

Meliadi Mine, Katerini, Greece. Int. J. Coal Geol. 17, 51–67.

Kalkreuth, W., Riediger, C.L., McIntyre, D.J., Richardson, R.J.H.,

Fowler, M.G., Marchioni, D., 1996. Petrological, palynological

and geochemical characteristics of Eureka Sound Group coals

(Stenkul Fiord, southern Ellesmere Island, Arctic Canada).

Int. J. Coal Geol. 30, 151–182.

Kaouras, G., 1989. Kohlenpetrographische, palynologische und

sedimentologische Untersuchungen der Pliozanen Braunkohle

von Kariochori bei Ptolemais/NW Griechenland. PhD Thesis,

Georg-August-Universitat, Gottingen. 220 + 38 pp.

Kolcon, I., Sachsenhofer, R.F., 1999. Petrography, palynology and

depositional environments of the early Miocene Oberdorf lignite

seam (Styrian Basin, Austria). Int. J. Coal Geol. 4, 275–308.

Koukouzas, C., Kotis, T., Ploumidis, M., Metaxas, A., 1981. Coal

exploration of ‘Apofysis’ field of Anargiri –Amynteon area

(W. Macedonia). Research for energy sources, No. 1, Institute

of Geological and Mining Research. 52 pp. (in Greek with

English abstract).

Kuder, T., Kruge, M.A., Shearer, J.C., Miller, S.L., 1998. Environ-

mental and botanical controls on peatification—a comparative

study of two New Zealand restiad bogs using Py-GC/MS, pet-

rography and fungal analysis. Int. J. Coal Geol. 37, 3–27.

Ligouis, B., Lu, J., Pils, J., 1998. Coal petrology and Rock-Eval

pyrolysis of a coal seam in the Oligocene Molasse near Mies-

bach (Upper Bavaria, Germany): coal depositional environ-

ments. Bull. Soc. Geol. Fr. 169, 381–393.

Markic, M., Sachsenhofer, R.F., 1997. Petrographic composition

and depositional environments of the Pliocene Velenje lignite

seam (Slovenia). Int. J. Coal Geol. 33, 229–254.

Neavel, R.C., 1966. Sulfur in coal; its distribution in the seam and

in mine products. PhD Thesis, Penn State Univ. 332 pp.

Pavlides, S.B., Mountrakis, D.M., 1986. Neotectonics of the Flo-

rina–Vegoritis–Ptolemais Neogene Basin (NW Greece): an ex-

ample of extensional tectonics of the greater Aegean area. Ann.

Geol. Pays Hell. 33 (1), 311–327.

Petersen, H.I., 1993. Petrographic facies analysis of Lower and

Middle Jurassic coal seams on the island of Bornholm, Den-

mark. Int. J. Coal Geol. 22, 189–216.

Querol, X., Cabrera, Ll., Pickel, W., Lopez-Soler, A., Hagemann,

H.W., Fernandez-Turiel, J.L., 1996. Geological controls on the

quality of the Mequinenza subbituminous coal deposit, northeast

Spain. Int. J. Coal Geol. 29, 67–91.

Rimmer, S.M., Hower, J.C., Moore, T.A., Esterle, J.S., Walton, R.L.,

Helfrich, C.T., 2000. Petrography and palynology of the Blue

Gem coal bed (Middle Pennsylvanian), southeastern Kentucky,

USA. Int. J. Coal Geol. 42, 159–184.

Shearer, J.C., Moore, T.A., 1994. Botanical control on banding

character in two New Zealand coal beds. Palaeogeogr. Palaeocl.

Palaeoecol. 110 (1), 11–28.

Singh, M.P., Singh, A.K., 2000. Petrographic characteristics and

depositional conditions of Eocene coals of platform basins,

Meghalaya, India. Int. J. Coal Geol. 42, 315–356.

Teichmuller, M., Littke, R., Taylor, G.H., 1998a. The origin of

organic matter in sedimentary rocks. In: Taylor, G.H., Teichmul-

ler, M., Davis, A., Diessel, C.F.K., Littke, R., Robert, P. (Eds.),

Organic Petrology. Gebruder Borntraeger, Berlin. 704 pp.

Teichmuller, M., Taylor, G.H., Littke, R., 1998b. The nature of

organic matter-macerals and associated minerals. In: Taylor,

G.H., Teichmuller, M., Davis, A., Diessel, C.F.K., Littke, R.,

Robert, P. (Eds.), Organic Petrology. Gebruder Borntraeger,

Berlin. 704 pp.

Valceva, S., Georgakopoulos, A., Markova, K., 1995. The relation-

ship between petrographic composition and some chemical

properties for the Ptolemais Basin lignite, Greece. In: Pajares,

J.A., Tascon, J.M.D. (Eds.), Coal Science: Proc. 8th Int. Conf.

on Coal Science. Coal Science and Technology, vol. 24. Elsevier,

Amsterdam, pp. 259–262.

van Hoeve, M.L., 2000. Cyclic changes in the late Neogene vege-

tation of northern Greece. PhD Thesis, LPP Contributions Series

No. 12, Utrecht. 131 pp.