Directory UMM :Data Elmu:jurnal:O:Organic Geochemistry:Vol32.Issue1.2001:

Organic Geochemistry 32 (2001) 69±85
www.elsevier.nl/locate/orggeochem

Phenylnaphthalenes and polyphenyls in Palaeozoic source
rocks of the Holy Cross Mountains, Poland
Leszek Marynowski a,*, Franciszek Czechowski b, Bernd R.T. Simoneit c
a
Department of Earth Sciences, Silesian University, 60 BeËdzinska St., 41-200 Sosnowiec, Poland
Institute of Organic Chemistry, Biochemistry and Biotechnology, Wroc•aw University of Technology,
.
27 Wybrzeze WyspianÂskiego St., 50-370 Wroc•aw, Poland
c
Environmental and Petroleum Geochemistry Group, College of Oceanic and Atmospheric Sciences,
Oregon State University, Corvallis, OR 97331, USA

b

Received 24 January 2000; accepted 9 October 2000
(returned to author for revision 12 May 2000)

Abstract

Source rocks from a marine depositional setting from Palaeozoic formations in the Holy Cross Mountains region
(Midlands, Poland) were analysed for aromatics using capillary gas chromatography±mass spectrometry (GC±MS).
The occurrence of two novel series of aromatic hydrocarbons in these sediments, namely phenyl derivatives of fused
ring polycyclic aromatic hydrocarbons (PhPAH) and polyphenyls (PPh), was established. Furthermore, the methyl
derivatives of these compounds were also present. The chromatographic behaviour of the triaromatic members of the
series, i.e. two isomers of phenylnaphthalene (1-PhN and 2-PhN) and three isomers of terphenyl (o-TrP, m-TrP and pTrP) was evaluated using authentic standards. The isomeric composition of the phenylnaphthalenes (PhNs) and terphenyls (TrPs) was found to depend on thermal maturity. In the lower maturity samples abundances of 1-PhN and o-TrP
are higher. Increase in sample maturity is indicated by an increase in the relative abundance of 2-PhN as well as m-TrP
and p-TrP. Three thermal maturity parameters of the organic matter based on the relative abundances of the PhN and
TrP isomers are proposed: PhNR=2-PhN/1PhN, TrP1=p-TrP/o-TrP, and TrP2=(m-TrP+p-TrP)/o-TrP. In general
their values positively correlate with the vitrinite re¯ectance (Ro) and MDR, while correlation of the other biomarker
maturity parameters such as the Ts/Tm ratio are less apparent. The compounds above are believed to be geochemical
products from unknown precursors. A potential geochemical process of formation for the o-TrP is proposed, and
involves initial preservation of carbohydrates in sediments through sulfur incorporation, further dehydration, cyclisation and aromatisation to respective furan and/or thiophene derivatives, and ®nally reductive elimination of oxygen
and sulfur in the furan and thiophene products, respectively. # 2001 Elsevier Science Ltd. All rights reserved.
Keywords: Palaeozoic source rocks; Phenyl-polyaromatic hydrocarbons; Polyphenyls; Phenylnaphthalenes; Terphenyls; Maturity indices

1. Introduction
Aromatic hydrocarbon distributions in coals and
organic extracts of sedimentary rocks have received

* Corresponding author.
E-mail address: marynows@ultra.cto.us.edu.pl (L. Marynowski).

much attention, mainly because of their usefulness as
indicators of the thermal maturity of the sediments
(Radke et al., 1982; Radke and Welte, 1983; Alexander
et al., 1985, 1986; Cha€ee et al., 1986; Cumbers et al.,
1986, 1987; Radke, 1987, 1988; Yawanarajah and
Kruge, 1994; Willsch and Radke, 1995; Requejo et al.,
1996). Biphenyl and alkylbiphenyls, as well as alkylaromatics with fused aromatic rings are ubiquitous constituents of ancient sediments, as they occur in

0146-6380/01/$ - see front matter # 2001 Elsevier Science Ltd. All rights reserved.
PII: S0146-6380(00)00150-9

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L. Marynowski et al. / Organic Geochemistry 32 (2001) 69±85

comparable relative concentrations in various sediments
of terrestrial and marine origin (White and Lee, 1980;

Alexander et al., 1986; Radke, 1987; Fan Pu et al., 1991;
Trolio et. al., 1999).
The occurrence and formation of phenyl derivatives
of aromatic hydrocarbons have received much less
attention than their methyl analogues. The presence of
triaromatic members of these structures, i.e., phenylnaphthalenes (PhNs) and terphenyls (TrPs), in
organic-rich sediments has already been documented.
Phenyl substituted naphthalenes, i.e. 1-PhN and 2-PhN,
have been found in extracts from rocks of the Permian
Kupferschiefer Rote Fule zone (PuÈttmann et al., 1990)
and in late Permian organic-rich marl from northen
Italy (Sephton et al., 1999). Additionally, abundant
dibenzothiophenes and dibenzofurans in these sediments were noted. PhNs also are common aromatic
constituents of the extracts from bituminous coals
(White and Lee, 1980; Czechowski, unpublished data).
The ®rst indication of the occurrence of terphenyls in
high volatile bituminous coal was given by Bartle et al.
(1975) who used toluene supercritical extraction to
study coal liquefaction. Terphenyl (unidenti®ed isomer)
was also a prominent constituent in products of catalytic liquefaction of South African coals (So®anos and

Butler, 1989). The o-TrP in vitrinite from dull coal
(Radke et al., 1982) and recently m-TrP and p-TrP were
observed at comparable concentrations in higher rank
bituminous coals (Willsch and Radke, 1995). Also,
Cha€ee et al. (1986 and earlier references therein, p.
324) give tentative observation of p-TrP. However, no
extractable TrPs were found in sediments from marine
depositional environments.
Oxidation experiments have established that phenylpolyaromatic hydrocarbons are common structural
units in the macromolecular network of the coal matrix.
Aqueous sodium dichromate oxidation of Pocahontas
no. 3 coal produced a variety of aromatic hydrocarbons,
where PhNs, phenylanthracenes and phenylphenanthrenes, as well as biphenyl, terphenyls and quaterphenyls represented a high proportion of the hydrocarbons
released (Stock and Obeng, 1997). These authors suggested that linear polyphenyls are linkages in the coal
matrix, as such units are particularly resistant to oxidation. Additionally, oxidation of coal (Hayatsu et al.,
1975, 1982) and ¯ash pyrolysis of charcoal from the
samples representing the Cretaceous±Tertiary boundary
(Kruge et al., 1994) have revealed dibenzofurans in the
bituminous coals and polyaromatic matrices, with
structures related to phenyl-aromatics in the fossil

charcoal. Dibenzofuran and dibenzothiophene moieties,
from which biphenyl and its alkyl derivatives can be
formed, are also present in organic-rich sediments in the
unbound form, as they were extracted from Posidonia
shale and a Permian marine sediment (Radke and
Willsch, 1994; Sephton et al., 1999).

Due to the lack of an obvious natural product precursor, no source has yet been proposed to account for
the formation of more complex phenyl-polyaromatic
and polyphenyl compounds, and their geochemical
behaviour remains unrecognised.
The present paper reports the occurrence of other
phenyl-polyaromatic and polyphenyl compounds in
Palaeozoic sediments from the Holy Cross Mountains,
as well as the occurrence, and a detailed analysis of the
PhN and TrP isomeric composition for the assessment
of maturity. Their potential synthesis via multiple thermal alteration steps from carbohydrates (cellulose) is
suggested.

2. Geological setting

The Holy Cross Mountains (HCMts) are located in
the south-western part of Central Poland (the schematic
lithostratigraphy is illustrated in Fig. 1). They occupy an
area of about 3090 km, in which the Palaeozoic formations outcrop from the Mesozoic and Cenozoic (Miocene)
cover. The HCMts are situated between the Central European Variscides and East European Platform, close to
the Tornquist-Teisseyre tectonic zone. Due to the high
paleotectonic activity, the HCMts are divided into two
zones: northern, the so-called Lysogory Region, and
southern, the Kielce Region. Both zones are separated
by the Holy Cross dislocation (Fig. 1) interpreted on the
basis of geophysical investigations as a deep fracture
(Guterch et al., 1976). The Cambrian formations are the
oldest outcrops in the region with a thickness of around
2500±3000 m. They comprise shallow marine sandstone
with interbedded shale. Formations of the Ordovician
period are composed of thin shallow marine siliciclastics, overburdened gradually by carbonates. During the
Silurian period sedimentation was dominated by graptolitic black shales, where graywackies were deposited
on top. Their thickness does not exceed 2500 m. The
lower Devonian is characterised by terrigenous sediments, while during the middle and upper Devonian the
character of sedimentation changed, and consists exclusively of carbonates (carbonate platform and shelf

basin). The thickness of the Devonian formations
reached 2000 m. The carboniferous deposits consist of
black siliceous shales, organogenic limestones and siliciclastics. A stratigraphic gap in the upper carboniferous
formations is caused by the Variscian folds and uplifts.
The upper Permian deposits consist ®rst of basal breccia
and conglomerates, gradually changing to carbonates,
clastic and marly sediments, which close the Palaeozoic
sedimentation. The rocks have diversi®ed clay-mineral
assemblages. More detailed lithological and paleontological descriptions of the HCMts Palaeozoic formations
can be found in earlier work (Szulczewski, 1971, 1996;
Narkiewicz, 1988, Racki, 1992).

L. Marynowski et al. / Organic Geochemistry 32 (2001) 69±85

71

Fig. 1. Location of the Palaeozoic formations of Holy Cross Mountains area with lithological description and sample sites.

3. Analytical methods

3.3. Gas chromatography±mass spectrometry (GC±MS)

3.1. Vitrinite re¯ectance and TOC determination

GC±MS analysis was carried out with a HP5890 II
gas chromatograph equipped with a fused silica capillary column (30 m0.25 mm i.d.) coated with diphenylpolysiloxane phase (HP-5, 0.25 mm ®lm thickness).
Helium was used as a carrier gas. The GC oven was
programmed from 35 to 300 C at 3 C minÿ1. The gas
chromatograph was connected to a HP 5971A mass
spectrometer detector. The MS was operated at an ion
source temperature of 200 C, ionisation energy of 70
eV. Samples were analysed using full scan data acquisition (mass range m/z 40±600 with cycle time of 1 s) and
selected ion monitoring (SIM) modes. Phenylnaphthalenes and terphenyls were monitored using selective ion
monitoring of the molecular ions m/z 204 and 230,
respectively.

Vitrinite re¯ectance was measured on polished crosssections of the rock according to the standard procedure
used for coals (Davis, 1978).
A Leco carbon analyzer was used for the quantitation
of TOC contents. Carbonates were removed from the

samples by treatment with hydrochloric acid prior to
analysis.
3.2. Sample extraction and extract fractionation
The ®nely ground rock samples were exhaustively
Soxhlet-extracted in pre-extracted thimbles using dichloromethane:methanol (7.5:1, v/v). Asphaltenes were
removed from the extracts by precipitation in n-hexane.
The n-hexane solubles were further separated using preparative pre-washed silica gel TLC plates (Merck,
20200.025 cm). Prior to separation the TLC plates
were activated at 150 C for 3 h. Plates loaded with ca.
50 mg of the n-hexane soluble fraction were developed
with n-hexane. Bands comprising aliphatic (Rf 0.4±1.0),
aromatic (Rf 0.05±0.4) and polar (Rf 0.0±0.05) fractions
were collected and the organic material was recovered
from the silica gel with dichloromethane.

3.4. Arti®cial maturation of 1-PhN and o-TrP
A sample of 1-PhN or o-TrP (10 mg) mixed with
®nely ground aluminium montmorillonite (500 mg) was
placed into a glass tube, and after evacuation was sealed.
The sealed glass tubes were heated in a furnace for half

an hour at temperatures of 200, 300, 400 and 500 C for 1PhN/montmorillonite and 300, 400 and 500 C for oTrP/montmorillonite, respectively. After the period of

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L. Marynowski et al. / Organic Geochemistry 32 (2001) 69±85

heating at constant temperatures the ampules were
removed from the furnace, cooled to room temperature,
opened and extracted with dichloromethane for GC±
MS analysis. Appropriate blank experiments were carried out without 1-PhN or o-TrP being present.

by evaluations of CAI and biomarker maturity indices
revealed a temperature jump throughout the section
from the Kowala to the Kostomloty series. These were
assessed in the range of 40±60 C for the Kowala and
Panek series and a high increase to the range of 115±
160 C for the Kostom•oty section.

3.5. Pyrolysis of cellulose

4.2. Composition of the aromatic hydrocarbon fraction

Two samples of cellulose, pure Whatman cellulose
and cellulose separated from a Tertiary xylitic brown
coal using the procedure described elsewhere (Czechowski and Jezierski, 1997) were pyrolysed in an opensystem consisting of an electrically heated horizontal
quartz tube. A tablet (ca. 1 g) made from ®nely ground
cellulose was placed in the quartz tube. A constant ¯ow
of argon was passed through the tube to ensure rapid
removal of the volatilized pyrolysis products from the
heating zone. To further minimise secondary thermal
reactions the sample was heated up to 600 C by slow
introduction of the sample tube into the heating zone
from the argon inlet side. The volatile pyrolysis components carried out in the argon stream were absorbed into
n-hexane. The n-hexane solutions were then analysed
using GC±MS.

4. Results and discussion
4.1. Samples
The locations of the sedimentary rock samples analysed are shown in Fig. 1 while their geological ages and
some selected characteristics are given in Table 1. Samples analysed comprised carbonates (limestones and
dolostones) and shales (except sandstone from Gruchawka). They derived from boreholes (cores) as well as
from active and inactive quarries. The later were collected from sites of the minimal weathering. To avoid
contamination the samples, prior to powdering and
extraction, were ultrasonically washed in methanol.
Bitumens of the investigated rocks are autochtonous
(Marynowski, 1999).
In the area investigated the total organic carbon
(TOC) content ranges from 0.01 to 2%, and only in the
case of two Kowala shales analysed is it higher (4.0 and
23.3%). The maturities of the samples were within the
oil generation zone, viz. 0.5±1.2% Ro. The values of the
extract yields are rather small, usually below 80 mg of
extract per gram of TOC in the rock. The concentration
of saturated hydrocarbons varies from 8 to 76% and the
aromatic fraction usually makes up 9±40% of the total
extractable organic matter (Table 1).
The data on the conodont color alteration index (CAI)
of HCMts area are also listed in Table 1 (Belka, 1990),
while the biomarker maturity indices were described earlier (Marynowski, 1997). Geothermal histories assessed

The characteristic feature of aromatic hydrocarbon
fractions from samples of the Palaeozoic carbonate and
clastic rocks from the Holy Cross Mountains is their
uncommon molecular composition, compared to typical
aromatic hydrocarbons of marine sources from another
areas. An example of the aromatic hydrocarbon total
ion current (TIC) from a low maturity Radkowice
sample, illustrating the major identi®ed compounds, is
shown in Fig. 2. The dominant compounds are phenanthrene, chrysene and/or triphenylene. Other abundant
compounds include polyphenyls (PPhs), as well as phenyl
substituted fused-ring polycyclic aromatic hydrocarbons
(PhPAHs) represented mainly by phenylnaphthalenes
(PhNs), phenyl¯uorene and diphenyl¯uorene. The presence of polyaromatic sulfur compounds (dibenzothiophene, benzonaphthothiophenes and various benzobisbenzothiophenes, as well as their furan counterparts Ð
Fig. 2) is common in samples with high concentrations
of previously unreported PhPAHs and PPhs in the solvent extracts. The composition of the two novel groups
of aromatic compounds is illustrated in the summed ion
chromatograms characteristic for PhPAHs and PPhs
(Fig. 3a Ð m/z 154+204+254+304 and Fig. 3b Ð m/z
154+168+230+244+306+320+382+396+458+472).
In the sample discussed the PhPAH are comprised of
phenylnaphthalenes (PhNs), phenylphenanthrenes, binaphthyls, tetraphenylene and, while the PPh are comprised of biphenyl, terphenyls (TrPs), quaterphenyls,
quinquephenyls and sexiphenyls as well as their methylated derivatives, with the ortho substitution pattern
dominant. Relatively abundant dibenzofuran is also
shown in Fig. 3b. The identi®cation of all PhN, TrP and
binaphthyls isomers as well as tetraphenylene was
achieved by comparison of the retention times and mass
spectra of representative peaks in the ion chromatograms
with the data of the authentic standards (Aldrich).
Binaphthyls were synthetized according to Copeland et al.
(1960). Other described compounds are tentatively identi®ed on the basis of chromatographic behaviour and
mass spectral interpretation (Fig. 3b).
4.3. Maturity trends of PhNs and TrPs
The triaromatic members of the new series, PhNs and
TrPs, are found in all samples investigated. They are
apparently the phenyl analogues of methylnaphthalenes
and methylbiphenyls. The PhN isomers were detected as

73

L. Marynowski et al. / Organic Geochemistry 32 (2001) 69±85
Table 1
Geochemical characteristics of the samples from the Holy Cross Mountains and their extracts

No.

Locality

Lithology

Age

CAla

Ro
(%)

TOC
(%)

EOM
(mg/g
TOC)

Aliph.
(%)

Arom.
(%)

NSO+
Asph
(%)

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32

Wis nioÂwka
MoÂjcza
Gruchawka
Bukowa GoÂra
Zache•mie
Do•y Opacie
Radkowice
Radkowice
Radkowice
Jurkowice
SÂwieËtomarz
—abeËdzioÂw
KarwoÂw
Budy
Wymys•oÂw
Laskowa GoÂra
Panek
GoÂra Zamkowa
DeËbska Wola
Kowala Quarry
Jaworznia
SitkoÂwka Kowala
JoÂzefka
Wietrznia
GoÂrno
SÂluchowice
Kostomloty
TudoroÂw
GoÂra —gawa
Kowala Quarry
BesoÂwka
Kadzielnia

Shale
Limestone
Sandstone
Shale
Dolostone
Dolostone
Dolostone
Green shale
Black shale
Shale
Sandstone
Dolostone
Limestone
Limestone
Limestone
Dolostone
Limestone
Limestone
Limestone
Shale
Limestone
Limestone
Limestone
Limestone
Limestone
Shale
Shale
Limestone
Limestone
Shale
Limestone
Limestone

U. Cambrian
Llanvirn
Siegenian
Emsian
Eifelian
Eifelian
Eifelian
Eifelian
Eifelian
Eifelian
Eifelian
Givetian
Givetian
Givetian
Givetian
Givetian
Frasnian
Frasnian
Frasnian
Frasnian
Frasnian
Frasnian
Frasnian
Frasnian
Frasnian
Frasnian
Frasnian
Famennian?
Famennian
Famennian
Famennian
Famennian

±
1
±
±
±
±
1
1
1
2
3.5
±
1
2
±
±
±
1
1
1±1.5
±
±
1.5
±
2
1.5
3

±
±
nf
nf
nf
nf
nf
nf
nf
nf
nf
nf
nf
nf
0.76
1.22
nf
nf
nf
0.55
0.63
0.63
0.74
0.79
0.85
0.96
1.2
nf
0.52
0.53
0.67
0.82

0.13
0.11
0.09
0.07
0.03
0.03
2.30
1.13
9.80
0.26
0.05
0.03
0.01
0.15
0.14
0.37
0.14
0.03
0.03
4.00
0.01
0.25
0.53
0.32
0.28
0.97
0.53
0.37
0.73
23.00
0.32
0.10

59
37
33
43
50
20
37
10
29
38
240
50
100
93
107
11
21
233
67
30
200
68
57
47
31
94
94
19
27
40
6
120

42
35
65
47
17
26
22
51
8
27
30
20
36
31
40
30
25
29
39
10
16
18
45
76
71
54
55
37
15
15
36
71

40
28
19
19
22
30
13
26
17
35
18
30
22
35
16
28
22
27
26
25
18
24
20
14
3
29
9
11
17
26
31
23

18
37
16
34
61
44
65
23
75
38
52
50
42
34
44
42
53
44
35
65
66
58
35
10
26
17
36
52
68
59
33
6

Shale
Limestone
Dolostone
Dolostone
Dolostone

Famennian
Frasnian
Givetian
Givetian
Eifelian

±
±
±
±
±

0.55
nf
0.64
nf
0.73

4.00
0.01
0.53
0.08
0.20

43
300
113
75
65

27
35
32
42
45

22
31
22
25
28

51
34
46
33
27

Limestone
Limestone
Dolostone
Dolostone
Dolostone
Shale
Shale

Famennian
Famennian
Givetian
Givetian
Givetian
Eifelian
Tournaisian

1.5±2
1.5±2
±
±
±
±
1±1.5

0.85
0.86
0.99
nf
nf
1.15
0.53

0.75
0.38
0.11
0.03
0.10
0.30
3.70

97
155
100
200
70
30
16

35
52
44
49
36
30
38

23
21
27
9
17
20
34

42
27
29
40
47
50
28

Shale
Limestone
Limestone

Visean
Zechstein
Zechstein

1.5±2
±
±

0.85
0.56
0.90

0.80
0.11
0.40

15
18
50

54
32
26

33
32
20

13
36
54

Kowala-1 borehole
33
- depth 39.8 m
34
- depth 318.8 m
35
- depth 633.2 m
36
- depth 732.5 m
37
- depth 955.5 m
Janczyce-1 borehole
38
- depth 73.7 m
39
- depth 229.7 m
40
- depth 705.1 m
41
- depth 943.0 m
42
- depth 951.5 m
43
- depth 1239.3 m
44
Jab•onna IG-1
borehole-depth 52.0
45
OstroÂwka
46
Ga•eËzice
47
KajetanoÂw
a

Data from Belka (1990).

1
1±1.5
1±1.5
1.5

74

L. Marynowski et al. / Organic Geochemistry 32 (2001) 69±85

Fig. 2. The aromatic compounds from a sample of Radkowice green shale (GC±MS total ion chromatogram). Legend: DBFudibenzofuran, DBT- dibenzothiophene, BNFu- benzonaphthofurans, BNTs- benzonaphthothiophenes, BBFu- benzobisbenzofurans,
BBTs- benzobisbenzothiophenes.

a characteristic group of two peaks in the m/z 204 ion
chromatogram and TrP isomers as a group of three
peaks in the m/z 230 ion chromatogram. Their mass
spectra are similar and show intense molecular and
doubly charged molecular ions. It was shown that 1PhN elutes before 2-PhN, while the TrPs elute in the
order: o-TrP, m-TrP and p-TrP. The retention behaviour determined here for the PhNs and TrPs is in
agreement with those reported for standard polycyclic
aromatic hydrocarbons (Lee et al., 1979).
The isomeric ratios of these compounds vary with the
level of thermal maturity, and the potential of their use
as maturity indicators was explored. The maturation
behaviour of the PhNs and TrPs is similar to their
methylnaphthalene and methylbiphenyl analogues. Distribution patterns of PhNs and TrPs for selected samples
of increasing maturity (based on Ro) are presented in
Fig. 4. In the lower maturity sample (Ro=0.52%) a
marked predominance of 2-PhN over 1-PhN and o-TrP
over the m-TrP and p-TrP isomers occurs. Systematic
changes in isomer constitution are observed with
increasing maturity of the samples. Isomerisation of the
TrPs with increasing maturity is proposed to account for
these e€ects and may be explained in terms of the relative
thermodynamic stabilities of the respective isomers.
The isomers of TrP can be considered as phenyl-substituted biphenyls and therefore the same maturity
principle can be applied as to the methylbiphenyls.

Indeed, in the Palaeozoic rocks the observed high predominance of o-TrP during early catagenesis decreases
with increasing maturity on advanced stages of catagenesis where m-TrP and p-TrP become gradually more
abundant (Fig. 4). The driving force for such a shift is
the reduction of steric hindrance of the o-TrP isomer.
The observed maturity trend in the relative abundances
of the isomers re¯ects the stability of the TrPs which
appears to be in the order: m-TrP>p-TrP>o-TrP. This
is in agreement with a general rule applied to substituted
aromatic ring systems, where compounds with meta
substituents are most stable, and those with ortho substituents are least stable. Literature data of TrP isomer
stabilities evaluated from the molar enthalpies of formation con®rm that m-TrP is thermodynamically the
most stable isomer (Verevkin, 1997). The PhN isomerisation is more advanced compared to that of the
TrPs for a given level of maturity.
Both compound classes have been used to develop
maturity indicators de®ned as the ratios of particular
isomers of di€erent stability. This is based on the
experimental evidence that the initially formed thermodynamically least stable 1-PhN and o-TrP have undergone further thermocatalytic isomerisation in more
mature sediments to the higher stability isomers of
PhNs and TrPs by phenyl shifts catalysed by Lewis
acids (e.g. admixtures of clay constituents contained in
the carbonate rocks). The proposed maturity indicator

L. Marynowski et al. / Organic Geochemistry 32 (2001) 69±85

75

Fig. 3. Partial summed mass chromatograms of the aromatic fraction isolated from a sample of Radkowice green shale: (a) biphenyl,
phenylnaphthalenes, binaphthyls, indeno[2,3-b;3,4-c]¯uorene, phenylphenanthrenes, tetraphenylene and phenyltriphenylenes (m/z
154+ 204+ 254+ 304), (b) biphenyl, methylbiphenyls and dibenzofuran, terphenyls, (*) methylterphenyls, (&) phenyldibenzofurans, (!) quaterphenyls, (?) methylquaterphenyls, quinquephenyls, methylquinquephenyls, sexiphenyls and methylsexiphenyls (m/z
154+ 168+ 230+ 244+ 306+ 320+ 382+ 396+ 458+ 472).

for the PhNs, designated as PhNR, is expressed as the
relative abundance of the more stable 2-PhN to the less
stable 1-PhN:
PhNR ˆ 2-PhN=1-PhN
A corresponding rearrangement of o-TrP to m-TrP and
p-TrP, the thermodynamically more stable two isomers,
allows the proposal of two maturity parameters for TrPs:
TrP1 ˆ p-TrP=o-TrP

TrP2 ˆ …m-TrP ‡ p-TrP†=o-TrP
The respective values of the de®ned maturity indicators are presented in Table 2. The correlations of the
PhNR and TrP1 indices are shown in Fig. 5 versus
vitrinite re¯ectance (Ro) in a range of 0.5±1.4%, and the
maturity indicators of other marker compounds: MDR
(methyldibenzothiophene ratio, Radke et al., 1986) and
Ts=Tm ratio (pentacyclic terpanes). The trends of the
illustrated correlations are generally similar and exhibit
positive regressions, i.e. a steady increase with higher

76

L. Marynowski et al. / Organic Geochemistry 32 (2001) 69±85

Fig. 4. Partial mass chromatograms of phenylnaphthalenes (m/z 204) and terphenyls (m/z 230) of the aromatic fraction of selected
samples with increasing maturity: (a) Gora Lgawa, Ro=0.52%; (b) SitkoÂwka- Kowala, Ro=0.63%; (c) Janczyce-1 (depth 1239.3 m),
Ro=1.15%.

maturity. The isomerisation of the phenylaromatics,
similarly as the alkylaromatic compounds, is catalysed
by acids and therefore likely to be a€ected by variations
in sediment components, such as clay minerals. It was
recognised earlier that the lithology of source rocks may
a€ect the distribution of aromatic sulfur compounds
(Connan et al., 1986; Chakhmakhchev and Suzuki,
1995). This explains the wide scatter of the data points
over the overall correlation zones shown in Fig. 5, particularly high in the case of correlations with Ts=Tm
ratio (Fig. 5c and f), which is believed to be due to the
variations in the mineral matrix assemblages of the
Palaeozoic rocks from the HCMt formations. This factor
is partly responsible for the deviations in relative abundances of the compounds used in the maturity parameters. However, the in¯uence of the mineral matrix
factor on the catalytic potential of the sediment is dicult to assess and therefore the observed PhN and TrP
isomeric compositions are the net result of more complex
simultaneous processes. It should be noted, however,

that mature sediments from carbonate source rocks
where clay components are not present, exhibit a higher
proportion of 1-PhN and o-TrP isomers, whilst mature
samples derived from sediments containing clay components have higher proportions of 2-PhN as well as mTrP and p-TrP isomers.
4.4. Arti®cial thermal maturation of 1-PhN and o-TrP
To recognise the in¯uence of thermal maturity on the
distributions of PhN and TrP isomers arti®cial maturation experiments in the presence of montmorillonite
were carried out on the less stable isomers: 1-PhN and
o-TrP. The in¯uence of the mineral matrix was evaluated by performing the same experiments using dolomite. Isomerisation over montmorillonite of 1-PhN
occurs at lower temperature (200 C) than that of o-TrP
which started at about 300 C. Clay-catalysed isomerisation reactions start at these temperatures resulting in generation of higher abundances of the respective

77

L. Marynowski et al. / Organic Geochemistry 32 (2001) 69±85
Table 2
Biomarker maturity indicators of the bitumen in samples from the Holy Cross Mountains
No. Locality

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32

Wis nioÂwka
MoÂjcza
Gruchawka
Bukowa GoÂra
Zache•mie
Do•y Opacie
Radkowice
Radkowice
Radkowice
Jurkowice
SÂwieËtomarz
—abeËdzioÂw
KarwoÂw
Budy
Wymys•oÂw
Laskowa GoÂra
Panek
GoÂra Zamkowa
DeËbska Wola
Kowala
Jaworznia
SitkoÂwka Kowala
JoÂzefka
Wietrznia
GoÂrno
SÂluchowice
Kostomloty
TudoroÂw
GoÂra —gawa
Kowala
BesoÂwka
Kadzielnia

Kowala-1 borehole
33
- depth 39.8 m
34
- depth 318.8 m
35
- depth 633.2 m
36
- depth 732.5 m
37
- depth 955.5 m
Janczyce-1 borehole
38
- depth 73.7 m
39
- depth 229.7 m
40
- depth 705.1 m
41
- depth 943.0 m
42
- depth 951.5 m
43
- depth 1239.3 m
44
Jab•onna IG-1
borehole- depth 52.0 m
45
OstroÂwka
46
Ga•eËzice
47
KajetanoÂw
a
b
c
d
e
f
g

DMNc TrMNd MDRe DMDBTf TMDBTg PhNR TrP1
Ts/Tm C29Ts/C29Ha Index
MB-MDFb
±
1.00
0.21
±
0.79
0.78
0.47
0.50
0.51
1.95
0.26
0.26
0.74
0.27
1.30
±
0.65
0.55
0.35
0.23
1.29
0.16
1.47
2.51
3.08
±
6.56
0.45
0.10
0.21
0.67
1.38

±
0.51
0.20
±
0.35
0.25
0.43
0.30
0.46
0.40
0.15
0.12
±
0.15
0.59
±
0.30
0.22
0.09
0.38
0.63
0.15
0.49
1.08
1.30
±
1.78
0.73
0.14
0.37
0.33
0.66

0.90
0.29
0.12
0.67
0.35
±
0.24
0.37
0.27
0.47
0.17
0.10
0.25
0.09
0.50
0.62
0.18
±
0.09
0.13
0.32
0.13
0.40
0.22
0.38
0.69
0.90
0.06
0.13
0.22
0.20
0.30

0.42
0.29
0.21
0.33
0.23
±
0.17
0.25
0.13
0.23
0.20
0.20
0.20
0.21
0.26
0.48
0.25
0.23
0.28
0.23
0.24
0.21
0.19
0.30
0.27
0.36
0.51
0.22
0.16
0.14
0.24
±

0.94
0.82
0.54
0.90
0.77
±
0.45
0.53
0.41
0.77
0.70
0.67
0.68
0.50
0.78
0.96
0.47
0.52
0.72
0.45
0.72
0.47
0.81
0.90
0.85
0.91
0.97
0.62
0.44
0.42
±
±

4.70
5.00
2.27
9.38
8.33
2.17
1.07
0.64
0.73
1.83
2.27
1.44
2.50
1.39
3.43
25.00
1.46
1.71
1.92
0.93
2.27
1.39
2.50
3.57
5.00
12.50
6.25
1.79
1.47
0.73
1.92
2.78

0.78
0.90
0.61
1.00
2.25
±
0.25
0.12
0.18
0.42
0.54
0.46
0.67
0.44
0.71
3.00
0.29
0.53
0.45
0.57
0.77
0.40
0.75
0.74
0.67
3.00
2.02
0.53
0.28
0.40
0.48
0.76

1.76
2.10
1.90
2.35
5.29
±
0.54
0.49
0.44
1.00
1.25
1.30
1.32
1.00
1.55
8.10
1.14
1.26
1.12
1.50
0.60
0.76
1.61
4.11
1.61
5.29
4.30
1.37
0.70
0.67
2.47
1.73

15.7
4.0
3.3
24.0
6.1
3.8
1.4
1.9
2.3
1.9
4.0
3.8
1.9
2.4
2.1
15.7
2.8
3.8
2.3
2.7
3.5
3.5
2.8
3.2
5.3
15.7
10.1
1.7
2.2
1.2
2.7
6.7

0.22
0.34
0.26
0.60
0.72

0.30
0.22
0.17
0.23
0.45

0.20
0.21
0.26
0.24
0.53

0.26
0.27
0.26
0.25
0.24

0.73
0.66
0.60
0.58
0.65

0.52
2.27
1.50
2.27
1.79

0.32
0.63
0.44
0.56
0.52

0.57
1.54
0.92
1.32
0.85

1.3
3.3
2.2
2.3
3.2

1.72
2.84
±
±
±
±
0.69

0.53
1.11
±
±
±
±
0.29

0.27
0.45
0.48
0.51
0.77
0.91
0.38

0.21
0.31
0.32
0.20
0.42
0.49
0.25

0.83
0.89
0.89
0.69
0.91
0.97
0.72

1.79
4.17
8.33
4.17
8.33
25.00
0.76

0.52
0.83
1.69
0.70
1.82
6.00
0.34

1.06
1.54
3.36
2.39
5.00
6.73
0.70

1.9
5.7
4.3
6.1
4.6
32.3
0.6

2.51
0.21
1.20

0.97
0.15
0.55

0.33
0.09
0.45

0.33
0.21
0.38

0.84
0.61
0.93

3.13
2.00
4.40

±
0.60
0.93

±
1.19
1.50

4.0
2.6
13.3

TrP2

10.5
16.0
2.9
5.3
0.45
1.45
17.0
54.0
3.43
8.0
2.
9.17
0.46
1.61
0.10
0.31
0.31
0.95
0.34
1.04
2.27
8.36
0.92
2.72
0.2
0.72
0.61
1.68
0.63
1.76
28.0 101.0
0.73
1.73
0.55
1.82
0.96
2.48
0.48
1.85
0.34
0.88
0.81
2.9
0.18
0.51
0.56
1.56
1.9
6.3
2.4
5.6
2.5
4.3
0.28
0.63
0.19
0.81
±
±
0.41
1.19
1.11
3.42
±
0.71
0.57
0.43
1.14

±
2.1
1.14
1.22
4.21

0.81
1.48
1.56
4.31
1.37
2.83
1.04
2.59
1.00
2.25
50.0 114.0
0.13
0.5
0.94
0.3
9.71

3.44
0.81
22.9

C29Ts/C29H- 18a(H)-30-norhopane/C2917a(H)-hopane (Peters and Moldowan, 1993).
MB-MDF index- (3-MB+4-MB)/ (3-MB+4-MB+4-MDF+2 and 3-MDF+1-MDF);- MB- methylbiphenyl. MDF- methyldibenzofuran.
DMN-dimethylnaphthalene ratio (2,6- and 2,7-DMN)/ (2,6- and 2,7-+1,6-+1,4- and 2,3- and 1,5-+1,2-DMN) (Yawanarajah and Kruge, 1994).
TrMN- trimethylnaphthalene ratio (1,3,7-+1,3,6-+2,3,6-TMN)/(1,3,7-+1,3,6-+2,3,6-+1,2,5-TMN) (Yawanarajah and Kruge, 1994).
MDR- methyldibenzothiophene ratio: 4-MDBT/1-MDBT (Radke et al., 1986).
DMDBT- dimethyldibenzothiophene ratio: 2.4-DMDBT/1.4-DMDBT (Chakhmakhchev et al., 1997).
TMDBT- trimethyldibenzothiophene index of isomers ratio with unknown structures (Chakhmakhchev et al., 1997).

78

L. Marynowski et al. / Organic Geochemistry 32 (2001) 69±85

Fig. 5. Cross plots showing a correlation between the maturity indices, PhNR (plots a, b and c), TrP1 (plots d, e and f) vs. vitrinite
re¯ectence, Ro, methyldibenzothiophene ratio, MDR, and pentacyclic triterpane, Ts/Tm, ratio. A logarithmic scale is used for both
horizontal and vertical axes.

thermodynamically more stable isomers (TIC traces of
the reaction products are shown Fig. 6). The relative
proportion of more stable PhN and TrP isomers to less
stable isomers increases with increasing temperature. An
increase of the heating temperature up to 500 C in
intervals of 100 favours the gradual increase in abundance of more thermodynamically stable isomers: 2PhN, m-TrP and p-TrP (Fig. 6), as appears to occur
with increasing maturity in sediments (Fig. 4). At higher
temperatures more side products are generated. From 1PhN abundant decomposition and cyclisation products
besides 2-PhN have formed: naphthalene, biphenyl,
¯uoranthene and in lesser amounts methylphenylnaphthalenes and methyl¯uoranthenes. Similarly, from oTrP the products consisted of m-TrP and p-TrP as well as
naphthalene, biphenyl, ¯uorene, phenanthrene, triphenylene, methylterphenyls and phenyl¯uorenes. The cyclisation of o-TrP to triphenylene, which occurs already at
300 C, is consistent with the similar cyclisation of orthomethylbiphenyl to ¯uorene (Kagi et al., 1990). Fluorene
derivatives with additional phenyl substituent(s) are also
found in the natural samples (Fig. 2). They are cyclisation products of the ortho-substituted methyl-TrP at the
terminal phenyl ring. The high abundance of the

observed structures indicates that in the case of methylderivatives of TrP cyclisation through the methylene
bridge to a ®ve membered ring proceeds preferentially
compared with respective cyclisation between orthosubstituted phenyls resulting in formation of a sixmembered ring. Also maturity-related trends in the distribution of PhNs and TrPs evaluated from arti®cial
maturation experiments (due to high temperature and
short reaction time) can not be directly related to
natural maturation of the organic sediments, however, the observed trends are consistent to those in
natural samples.
Acid-catalysed isomerisation results in an equilibrium
mixture of the terphenyl isomers. Evidence for equilibrium in thermocatalytic isomerisation derives from
laboratory heating experiments performed with p-TrP
over montmorillonite at 400 C, from which the same
distributions were obtained as by heating of o-TrP. This
is due to isomerisation reactions resulting in the interconversion of the isomers. However, it is important to
note that no isomerisation of 1-PhN and o-TrP occurred
with dolomite up to temperatures of 500C. This explains
why in samples of carbonate matrix the relative concentration of the less stable isomers, 1-PhN and o-TrP,

L. Marynowski et al. / Organic Geochemistry 32 (2001) 69±85

is higher and is re¯ected by lower values of the PhNR,
TrP1 and TrP2 maturity indices (Tables 1 and 2).
The lateral distribution of the MDR and TrP1
maturity indices over the investigated area of the
HCMts is presented in Fig. 7. The values clearly indicate
a much higher geothermal gradient in the NW part of
the area, particularly around the Kostomloty, Laskowa,
WisnioÂwka and Zachelmie locales.

79

4.5. Origin of the phenylnaphthalenes and terphenyls
The presence of PhPAH and PPh compounds as common constituents in Palaeozoic HCMts strata inspired the
search for a possible biological precursor source of these
structures. As is well documented, only a minority of the
PAH compounds present in fossil fuels inherited their
structure directly from biosynthetic compounds, while

Fig. 6. Mass chromatograms revealing the distributions of PhNs and TrPs in the clay catalysed thermal rearrangement products of:
(a) 1-PhN and (b) o-TrP. Legend: MePhN- methylphenylnaphthalenes, MeFl- methyl¯uoranthenes, PhF- phenyl¯uorenes, MeTrPhmethyltriphenylenes.

Fig. 7. Spatial distribution of the kerogen maturation parameters: MDR and TrP1 of selected sediment samples from the Holy Cross
Mountains region.

80

L. Marynowski et al. / Organic Geochemistry 32 (2001) 69±85

the vast majority of PAHs are the products of complex
geochemical transformations of naphthenic and/or ole®nic biological precursors (Radke, 1987, Simoneit, 1998).
The skeletons of the PhPAH and PPh compounds discussed here are not known to be synthesised by living
organisms (Barton et al., 1999), and, therefore, cannot
be attributed directly to known biological precursors
without signi®cant structural changes. The lack of a
simple structural relationship to speci®c natural product
precursors has led us to suggest that these compounds
are geochemical diagenetic products formed via geosynthetic processes involving the structural rearrangement
of other biological compounds.
The literature describes few possibilities which could
be considered for an origin of these structures observed
in nature. Some examples are described. (i) Generation
of phenyl substituted PAHs in ancient vegetation ®res.
As established by Killops and Massoud (1992), pyrolytic origin PAHs in Upper Jurassic strata contained
more stable isomer of PhN i.e. 2-PhN. (ii) Shock wave
synthesis of PAHs from benzene, which resembles a
pyrolytic reaction of benzene at high temperatures, produced higher-molecular weight PAHs, ranging from 128
(naphthalene) to 306 da (quaterphenyl) (Mimura, 1995),
with phenylnaphthalenes and terphenyls of broadly
similar isomeric composition as observed in more mature
samples analyzed here. The relative concentration of the
respective isomers was in the order: m-TrP>p-TrP>oTrP and 2-PhN>1-PhN. Direct copyrolysis of benzene
and naphthalene in vacuum at 530 C resulted in formation of isomeric phenylnaphthalenes, terphenyls (2-PhN
and m-TrP dominant) with cyclodehydrogenation products of 1-PhN and o-TrP, i.e., ¯uoranthene and triphenylene, respectively (Perez and Cristalli, 1991).
However, free radical reactions in kerogen maturation
occur at rather advanced stages of catagenesis. The
processes above cannot be excluded as supplementary to
the formation of PhPAH and PPh compounds during
late catagenesis, but are excluded in these relatively
immature samples where these compounds are already
observed with a speci®c ortho isomeric prevalence. (iii)
The low temperature formation of C±C bonds between
two 6-membered and other polyaromatic rings could
proceed via an oxidative coupling process with phenolic
precursors (which are widespread in natural systems as
revealed by pyrolysis, Senftle et al., 1986; Senftle and
Larter, 1987), or by electrophilic substitution proceeding easily with phenolic compounds. These reactions
might occur during the accumulation and diagenesis of
sedimentary organic matter. (iv) Structures possessing
unsaturated polyene chains are known to be present in
recent sediments. Cyclisation and aromatisation of linear polyene chains in some carotenoids, are considered
as an alternative pathway. It is well established that
among the numerous polyalkylaromatic diagenetic and
catagenetic products from the diaromatic carotenoid

isorenieratene, also highly alkylated structures with
additional aromatic rings are generated (via an intramolecular Diels±Alder cyclisation of the polyene isoprenoid
chain followed by aromatisation), i.e., possessing biphenyl or phenylnaphthalene moieties (Koopmans et al.,
1996). In the samples analysed such structures are not
observed and there is no indication for the occurrence of
speci®c biomarkers derived from isorenieratene, which
are characteristic of photic-zone anoxia in the depositional settings (Koopmans et al., 1996, Sinninghe
Damste and Koopmans, 1997). Because of the absence
of aryl and diaryl isoprenoids in most of the samples,
this pathway of PhN and TrP formation was excluded.
A characteristic feature of the PAHs from the
Palaeozoic rocks of the HCMts is the higher abundance
of polycyclic aromatic sulfur and polycyclic aromatic
oxygen compounds. Particularly dibenzofurans, benzonaphthofurans, dibenzothiophenes, benzonaphthothiophenes and polybenzothiophenes contribute signi®cantly
to the aromatic hydrocarbon fraction. Generation of
alkylbenzenes and benzo[b]thiophenes was observed in
the products from arti®cial thermal maturation of highsulfur coal (Radke and Willsch, 1993). Similar structures
possessing a furan or thiophene ring resulted from the
pyrolysis of sulfurised carbohydrates. The dominance of
such aromatic hydrocarbons and their furan and thiophene derivatives was also found as a characteristic for
the Rote Fule zone of the Kupferschiefer (PuÈttmann et
al., 1990, 1998), a sediment of marine origin. This suggests that they are not derived exclusively from higher
plants. Thus, the abundance of these compounds in the
bitumen of Palaeozoic strata from the HCMts indicates
an obvious similarity of the observed composition with
products generated from kerogen of terrigenous and/or
marine origins. This led to the supposition that a common carbon source for various depositional environments might be polysaccharides, which could have
contributed to the deposition and preservation of the
organic matter. Carbohydrates may originate from terrestrial, macroalgal and planktonic sources. This supposition is further supported by the presence of furan and
thiophene polyaromatic compounds in the samples which
are indicative for carbohydrates and their sulfurised products contributed to sediments. In contrast to the early
proposal that carbohydrates are preferentially degraded
and do not contribute signi®cant amounts of organic
carbon to sediments (de Leeuw and Largeau, 1993;
Tyson, 1995), it has recently been shown that carbohydrates form a large fraction of the sedimentary organic
matter as a result of their early diagenetic sulfurisation
(van Kaam-Peters et.al., 1998; Sinninghe Damste et al.,
1998). The occurrence of a carbohydrate sulfurisation
process in the natural environment has recently been
con®rmed by simulation experiments of the sulfurisation of glucose, cellulose and other carbohydrates with
inorganic sul®de, polysul®de and hydrogen sul®de

L. Marynowski et al. / Organic Geochemistry 32 (2001) 69±85

Fig. 8. Tentative reaction scheme for the formation of o-TrP from polysaccharides.

81

82

L. Marynowski et al. / Organic Geochemistry 32 (2001) 69±85

(Moers et al., 1988; Kok et al., 1997; Gelin et al., 1998),
which resulted in sulfur incorporation yielding carbohydrate (macro)molecules as non-extractable sulfurised residues. Pyrolysis/evaporation products of this sulfurised
residue yielded several thiophene compounds with a
molecular ®ngerprint identical to that found in natural
samples. In this way carbohydrates may be preserved in
sediments in a form that is resistant to microbial attack,
and thus have a greater potential for survival during
diagenesis than the carbohydrate precursor itself.
A similar process may have occurred during the
deposition of the Palaeozoic sediments from the HCMts.
It is well documented that sulfurisation of sedimentary
organic matter occurs predominantly in marine rather
than in lacustrine sediments, where sulfate required by
sulfate reducing bacteria to produce hydrogen sul®de is
usually limiting. Polysaccharides are widely distributed
in biota where they have both structural and energy
storage roles. A possible source for the carbohydrates
probably was carbohydrate-rich algal detritus, to which
sulfur was incorporated from hydrogen sul®de produced
by sulfate reducing bacteria resulting in low-temperature sulfur cross-linked (``vulcanized'') insoluble material. Sulfurised macromolecular carbohydrates in
carbonate sediments undergo multiple competitive
structural rearrangements (early dehydration reactions
yielding a variety of unsaturated products, then their

further cyclisation and aromatisation) during diagenesis
in the presence of clay. This generates various aromatic
hydrocarbon derivatives among which the furan and
thiophene moieties are formed as intermediates.
A tentative mechanism for the formation of orthoisomers of PPh via furan intermediates as for example
o-TrP is presented in Fig. 8. It involves intramolecular
dehydration of carbohydrate sub-units leading to the
formation of a conjugated double bond system within a
carbohydrate sub-unit, followed by reductive ring
opening and further intramolecular cyclisation to sixmembered cyclohexadienyl rings via Diels±Alder type
reactions. Further dehydration between the six-membered cyclohexadienyl rings and resultant aromatisation
yields a benzofuran derivative, i.e. trihydroxybenzo[1,2b:3,4-b0 ]bis[1]benzofuran. The ®nal step involves thermocatalytic removal of hydroxy groups and heteroatoms
under more reducing conditions, i.e., the cleavage of
the weaker C±O bonds in trihydroxybenzo[1,2-b:3,4b0 ]bis[1]benzofuran giving o-TrP (generally molecules
dominated by ortho-isomers of PPh compounds).
Additional carbohydrate sub-units involved in the reaction would result in the formation of further ortho-PPh
homologs: 1,10 ;20 ,100 ;200 ,1000 -quaterphenyl, 1,10 ;20 ,100 ;200 ,1000 ;
2000 ,20000-quinquephenyl, etc., the same structures as
observed in these sediments (Fig. 3). Similar reactions
could take place when thiophene derivatives are formed

Fig. 9. Mass chromatogram (TIC) products from pyrolysis of cellulose isolated from a xylitic brown coal. Inserts of m/z 204 and m/z
230 show the presence of phenylnaphthalenes and terphenyls in the pyrolysis products.

L. Marynowski et al. / Organic Geochemistry 32 (2001) 69±85

as intermediate structures from sulfurised polysaccharides. In that case the ®nal step could involve the
cleavage of C±S bonds in benzo[1,2-b:3,4-b0 ]bis[1]benzothiophene, or more generally in polybenzopolythiophene derivatives. Similarly, 1-PhN could be formed
from benzo[b]naphtho[2,1-d]furan or benzo[b]naphtho
[2,1-d]thiophene as intermediates via thermocatalytic
reductive heteroatom removal. These furan and thiophene intermediate structures indeed are present in less
mature samples (Fig. 3). Thermal stress acting on the
Kostomloty sample (Fig. 7) dramatically changed the
distribution of the aromatic compounds, resulting in a
total disappearance of thermodynamically unstable
benzofuran and benzothiophene intermediates.
The processes above, which take place at low maturity
(during diagenesis and early catagenesis, where aromatisation to benzofuran and benzothiophene derivatives is
completed), lead to the selective formation of a-substituted PhPAHs and ortho-isomers of PPhs. During
later catagenesis they undergo Lewis-acid catalysed isomerisation where the more stable PhPAH and PPh isomers are formed, as was discussed for 1-PhN and o-TrP
earlier.
This interpretation of a proposed possible carbohydrate source for the PhPAH and PPhs is supported by
the analysis of cellulose pyrolysis products. The arti®cial
thermal maturation of cellulose separated from xylitic
brown coal was performed by pyrolysis (see Section 3).
GC±MS analysis of the pyrolytic products has revealed
the presence of the same furan derivatives as found in
the natural samples. Furthermore, PhN and TrP isomers showing a 1-PhN and o-TrP prevalence (insets of
m/z 204 and m/z 230 mass chromatograms in Fig. 9)
were present among the variety of pyrolysis products.
The results obtained from the laboratory studies imply
that PhPAH and PPh structures are indeed, at least
partly, geosynthetic compounds originating from carbohydrates via reactions described above.

83

2-PhN, m-TrP and p-TrP. This e€ect has been attributed to thermally induced, clay catalysed, isomerisation
reactions, where 1-PhN is converted to 2-PhN and oTrP forms the meta and para isomers. Three new
maturity parameters based on the isomeric composition
of these compounds are proposed: the PhNR, the TrP1
and TrP2 ratios. The development of the PhNR, TrP1
and TrP2 indices was based on the assumption that 1PhN and o-TrP are the primary geosynthetic products
generated under depositional conditions and they
undergo isomerisation upon further maturation. The
newly proposed maturity indices PhNR, TrP1 and TrP2
show, however, only general correlation with the Ro and
MDR while correlation with Ts=Tm ratio is not satisfactory. It can be partly explained by clay catalysis,
which has been shown to be signi®cant in inducing the
isomerization reactions of the phenylnaphthalenes and
terphenyls.
A successful study of the product-precursor relationship has been achieved with evidence from laboratory
pyrolysis of cellulose for carbohydrate alteration as a
primary source of the PhNs and TrPs. This yielded a
variety of PhN and TrP compounds with isomer distributions similar to those found in the low maturity
sedimentary rocks. A tentative formation mechanism
for these aromatic structures via dehydration, cyclisation and aromatisation reactions has been proposed.
The data suggest that these compounds are geochemical
products derived from carbohydrates as possible precursors. Therefore, the presence of PhPAHs and PPhs in
the HCMts Palaeozoic strata is related to the preservation of carbohydrates in marine sediments by early
diagenetic sulfurisation processes. Multiple rearrangements of the sulfurised carbohydrates result in formation of aromatic furan and thiophene derivatives. This
view is supported by the abundant presence of aromatic
furans and thiophenes in the analysed sediments.

Acknowledgements
5. Conclusions
The occurrence of the two new groups of aromatic
hydrocarbons, namely PhPAHs and PPhs, as well as
their methyl derivatives, has been established for the
Palaeozoic, predominantly marine-derived sediments of
the Holy Cross Mountains area.
The members of the compound groups with three
aromatic rings, PhNs and TrPhs, are present in all
Palaeozoic sediments from the HCMts region. The isomeric compositions of the PhNs and TrPs are maturity
dependent. 1-PhN and o-TrP are the dominant isomers
in lower maturity sediments, and appear prior to the oil
generation window. As the maturity of the sediments
increases their relative abundances decrease at the
expense of the thermodynamically more stable isomers,

Financial support of this study by the Polish Research
Committee (KBN, grant no. 6 P04