Professor Salem Aboglila                                                           

Geochemistry & Environmental Chemistry science Faculty – Azzaytuna University-Libya

Mobile : 00218913700361

            :00218923394183

Email: salem.aboglila@gmail.com 

Address: Salem Abdul Ghni Aboglila / TIP 52945, Aramex House Old Bath Road Colnbrook, Slough,Berkshire SL3 0NS 

Nov 2010 PhD degree Thesis title: Organic and Isotopic Geochemistry of Source-rocks and Crude Oils from the East Sirte Basin (Libya). Curtin University of technology (palaeoenvironment study)

Eighty-five rock samples corresponding to the Palaeozoic formations were taken from two wells in

the NC 200 Block of the Murzuq Basin. The study aimed to find out geochemical characteristics of

parameters and specific Gas Chromatography-Mass Spectrometry (GC-MS) biomarkers were 

applied to determine the potential hydrocarbon generation. Per se, Rocks are good sources and 

hold fair content of organic matter, crossing in the range of good accumulation, in which the very 

good source rocks have an organic carbon richness (TOC) reached of 3.7 wt%. The studied rocks 

are ranged from immature to late mature organic matter (OM) with total organic carbon richness 

(TOC) range between 0.4 – 3.7 wt%. Rock-Eval parameters S1, S2, S3, Tmax, S2/S3, OI, PI and HI 

of the source rock samples have values ranged from 0.02 – 0.3, 0.22 – 6, 0.36 – 4, 423 – 443, 24= 

350, 0 – 0.27 and 42 – 384 respectively. The range of hydrogen index (HI) related to oxygen index 

(OI) displays that all kerogen types from Type II to Type III are exist and increase with depth. The 

Tmax parameter is wide-ranging among studied formations, indicating different levels of organic 

matter maturity, from immature oil window and to late mature for the Devonian-Carboniferous and 

Silurian source rocks, associated with more depth. Molecular composition analysis of n-alkanes and 

other biomarkers supported the findings of Rock-Eval pyrolysis data, revealing varied hydrocarbon 

signatures across the formations. The Carbon isotope analysis (δ13C) suggested multiple sources 

contributing to the generated oil, including Type I to Type III kerogens. Silurian Bir Tlacsin/Tanezzuft Formations, the Devonian Awaynat Wanin/BDS II Formations, and

Seven sedimentary rocks and seven crude oils undertook a geochemical analysis to describe their organic matter type and

then tag the Paleoenvironments based on the organic matter. The samples were collected from B1-NC151, A1-NC58, P1-

NC1, E1-NC174, D1-NC151, H29-NC115, and D1-NC174 boreholes, located in Murzuq Basin. The study was established to

understand life forms in the ecosystem based on biomarkers that biochemical techniques recognized. Microscopy was used

for kerogen typing and Spore Color Index reference. Organic matter (EOM) was extracted from cutting samples. Furthermore,

hydrocarbons were saturated and aromatic fractionated from the samples to investigate using Gas chromatograph system.

Spore color index (SCI), range between 1.5-3.5, Amorphous organic matter (AOM) from 42 to 95 percentage, Phytoclasts %

were 4-15.5, and Palynomorphs % range 0.5 to 7.5. The percentage of Carbon 85.66-86.29, Hydrogen 13.16-13.73, Nitrogen

0.06 -0.27, and Sulfur 0.31-0.70, besides wax were measured, ranging among 1.3 to 6.0 %. Pristine/n-C17, Phytane/n-C18,

Pristine/Phytane, carbon preference index measurements (CPI) and DBT/P as saturated hydrocarbon ratios from whole oil

chromatographs were established. Tricyclic terpanes, hopanes and n-alkanes were distinguishing as the most important oil

biomarkers that reserved the characteristics in the Paleoenvironments. 

greetings, I Hope you are doing well. Professor. Salem Aboglila Head of the Department of Environmental Science School of Basic Sciences Libyan Academy for Postgraduate Studies Tripoli – Libya

https://wavejo.com/editiorial-board-mebers

I am writing to let you know that you have got a formal confirmation letter, which is accompanied by this message as a PDF file.

If you need any additional information, feel free to contact me by email anytime.

Sincerely,

Dr. Fathia A. Mosa

Editor in Scientific Journal of the Faculty of Science-Sirte University.

The study area situated in the center of the Hameimat trough which is located in the southeast

of the Sirte basin. The Hameimat trough contains two of the largest oil fields in Libya,

Gialo and Abu-Attifel fields. The Upper Cretaceous Rachmat, Tagrifet, and Sirte

Formations are considered as the main source rock in Sirte Basin.

Organic geochemical study of the Upper Cretaceous Rachmat, Tagrifet and Sirte

Formations show these Formations have total organic carbon content values of 0.53% to

3.35% fair to excellent as source rock. The Kerogen types are type II and III mixed

continental and marine organic matter. The thermal maturity of these formations indicates a

mature stage in oil window.

Oil saturation index (OSI: S1*100/TOC) shows that Sirte and Rachamt formations have

low oil saturation, while the Tagrifet formation has good potential, where OSI exceeds 140

mg HC/g TOC in the most samples of the formation. The Tagrifet formation considers a

good unconventional reservoir for shale oil, where the Sirte and Rachmat formations

• consider possible for shale oil with high risk.

Certificates of re recognition from world environment

Salem Aboglila_Certificate from Journal

Abstract— Ninety-four rock samples were taken from the Middle to Late Devonian Awaynat Wanin, Early Carboniferous Marar, Late Carboniferous Assedjefar formations. The cuttings of Assedjefar Marar and Awaynat Wanin Formations collected from two wells, in the A1-163 oil field, locateed in the Murzuq Basin. RockEval Pyrolysis, Total Organic Carbon (TOC) and molecular biomarker (via the use of chromatographymass spectrometry, GC-MS) as geochemical parameters were applied to find out the types of kerogen, depositional conditions and level of organic matter maturity for representative samples. Such Formations are poor to excellent quantity of organic matter. Results of TOC related with remaining generation potential (S2) and hydrogen index (HI) data showed that the organic matter attributed to Type II/III and Type III kerogen (gas and oilprone organic matter), as well connected to S1 parameter indicated indigenous hydrocarbon exist. Ratios data of individual hydrocarbons, n-alkanes, isoprenoids and biomarkers parameters of Triterpanes and steranes indicate non-marine with marine organic matter deposited under non-marine conditions for Awaynat Wanin samples while Marar and Assedjiefar Formations deposited in nonmarine to deltaic conditions. The maturity data from Tmax, spore colour index and biomarker related parameters based on terpanes, steranes, and low molecular-weight hydrocarbons indicate the studied rocks are ranged from immature to mature.

Key Words— Awaynat Wanin Formation, Middle to Late Devonian, Kerogen, Biomarker, Rock Eval, Murzuq Basin

The Murzuq Basin, in Southwestern Libya, is one of Libyan’s most productive petroleum basins, with reserves estimated at 23 billion barrels recoverable of hydrocarbon equivalent within giant oil fields. Four crude oil samples collected from A1-NC186, E1-NC101, E2-NC101, H10-NC115 wells from Murzuq Basin, Libya, were suggested for bulk analysis and physical proprieties, alkane distribution and isoprenoids and the hopane, tricyclic terpane and sterane distributions of the oils, to confirm the presence of non-marine organic matter sources and/or any evidence of its existence. The oils show no significant variation in the ratios of the carbon, hydrogen, nitrogen and sulfur content (CHNS) composition. All samples recorded high to very high API° gravity, ranges 33.8 to 40.3; the sulfur values ranged from 0.31 to 0.45%, the wax ratio in crude oils is showing a great variety, E1-NC101and E2-NC101 oils show higher wax content, ranging from 6.1 to 6.7%. Pristineto Phytane ratios (Pr/Ph) range from 1.61 to 2.22 and the Pr/n-C17, Ph/n-C18, n-C17/n-C27 and CPI values determined as indicators of the depositional environment of the crude oils. The data of search confirmed that the crude oils were derived from marine, mixed and terrestrial sediments.

Drill cutting samples (n = 92) from the Devonian Awaynat Wanin Formation and Silurian Tanezzuft Formation, sampled from three wells F1, G1 and H1, locate in the northern edge of the Murzuq basin (approximately 700 kilometers south of Tripoli). The studied samples were analyzed in the objective of their organic geochemical assessment such as the type of organic matter, depositional conditions and thermal maturity level. A bulk geochemical parameters and precise biomarkers were estimated, using chromatography-mass spectrometry (GC-MS) to reveal a diversity of their geochemical characterizations. The rock formations are having varied organic matter contents, ranged from fair to excellent. The total organic carbon (TOC) reached about 9.1 wt%, ranging from 0.6 to 2.93 wt% (Awaynat Wanin), 0.5 to 2.54 wt% (Tanezzuft) and 0.52 to 9.1 wt% (Hot Shale). The cutting samples are ranged oil-prone organic matter (OM) of hydrogen index (HI) ranged between 98 –396 mg HC/g TOC, related kerogen types are type II and II/III, with oxygen index (OI): 6 - 190 with one sample have value of 366 mg CO2/g. Thermal maturity of these source rocks is different, ranging from immature to mature and oil window in the most of Tanezzuft Formation and Hot Shale samples, as reflected from the production index data (PI: 0.08 - 034). Tmax and vitrinite reflectance Ro% data (Tmax: 435 – 454 & Ro%: 0.46 - 1.38) for the Awaynat Wanin. Biomarker ratios of specific hydrocarbons extracted from represented samples (n = 9), were moreover used to study thermal maturity level and depositional environments. Pristine/Phytane (Pr/Ph) ratios of 1.65 - 2.23 indicated anoxic to suboxic conditions of depositional marine shale and lacustrine source rock.

This search aims to apply developed geochemical methods to a number of oils and source rock extracts to better establish the features of ancient environments that occurred in the Murzuq basin. Geochemical and geophysical approaches were used to confirm further a source contribution from other Paleozoic formations to hydrocarbon accumulations in the basin. One hundred and forty rock units were collected from B1-NC151, D1-NC174, A1-NC 76, D1-NC 151, F1-NC58, A1-NC 186, P1-NC 101, D1-NC 58, H1-NC58 and A1-NC58 wells. Seven crude oils were collocated A1-NC186, B1-NC186, E2-NC101, F3-NC174, A10-NC115, B10-NC115 and H10-NC115 wells. A geochemical assessment of the studied rocks and oils was done by means of geochemical parameters of total organic carbon (TOC), Rock-Eval analysis, detailed-various biomarkers and stable carbon isotope. The TOC values from B1-NC151 range 0.40% to 8.5%, A1-NC186 0.3% and 1.45, A1-NC76 0.39% to 0.74%, D1-NC151 0.40% to 2.00% to F1-NC58 0.40% to 1.12%. D1_NC174 0.30% to 10 %, P1-NC101 0.80% to 1.35%, D1-NC58 0.5% to 1.10%, H1-NC58 0.20% to 3.50%, A1-NC58 0.40% to 1.60%. The categories of organic matter from rock-eval pyrolysis statistics point to that type II kerogen is the main type, in association with type III, and no of type I kerogen recognized. Vitrinite reflectance (%Ro), Tmax and Spore colour index (SCI) as thermal maturity parameters reflect that the measured rock units are have different maturation levels, ranging from immature to mature sources. acritarchs distribution for most samples could be recognized and Palynomorphs are uncommon. Pristane to phytane ratios (> 1) revealed marine shale to lacustrine of environmental deposition. The Stable carbon isotope (δ 13C) values of seven rock-extract samples are -30.98‰ and -29.14‰ of saturates and -29.86‰ to -28.37‰ aromatic fractions. The oil saturate hydrocarbon fractions range between -29.36‰ to -28.67‰ and aromatic are among -29.98 ‰ to -29.55 ‰. The δ 13C data in both rock extractions and crude oils are closer to each other, typical in sign of Paleozoic age. It is clear that the base of Tanezzuft Formation (Hot shale) is considered the main source rocks. The Devonian Awaynat Wanin Formation as well locally holds sufficient oil prone kerogen to consider as potential source rocks. Ordovician Mamuniyat Formation shales may poorly contain oil prone kerogen to be addressed in future studies. An assessment of the correlations between the oils and potential source rocks and between the oils themselves indicated that most of the rocks extracts were broadly similar to most of the oils and supported by carbon stable isotope analysis results. 

This present paper includes a detailed evaluation of specific biomarkers together with stable carbon isotope (δ13C) by gas chromatography-mass spectrometry (GC–MS) and Gas Chromatograph– Isotope Ratio Mass Spectrometry (GC–IR–MS). Eight crude oil samples were collected from the A, B, H (east) and H (west) Fields, located in the Murzuq Basin, Libya. Stable Carbon isotope data (δ13C) together with biomarker ratios data of individual hydrocarbons, n-alkanes, isoprenoids, terpenes, hopanes, steranes and aromatic have been determined in crude oils to delineate their bacterial degradation, source facies, organic matter precursors, depositional conditions and a variation of maturation. Based on source-specific parameters including n-C19 alkane, % C27S, %C28S, %C29S, %C23TT, %C30αβ, %rC28, DBT/P, CPI, Pr/Ph, Ts/Tm, dh 30/h 30, 1 MN, 2 MN, 26-27 DMN, 15 DMN, 236 TMN, 146-135 TMN, 125 TMN, 136 TMN ratios and δ13C‰ of saturates and aromatics fractions. Such oils showed non-biodegradation, n-C19 peak proved oils generated from a Lower Palaeozoic source rocks as emphasizedvian-C19 peak, the dominance of C29steranes

over C27 and C28 with light Carbon isotope ratio (δ13C‰) values. The abundances of isosterane C29, C27, C28.Tricyclohexaprenol and bacteriohopane polyols and aminopolyols, recommended as mixture bioprecursors of tricyclic terpenes and hopanes, furthermore regular sterane ratio gives values characteristic of Lower Palaeozoic marine source rocks and holding green algae and most likely a quantity of contribution from acritarchs. Carbon preference indices (CPIs)>0.9 pointed to an anoxic deposition, dibenzothiophene to phenanthrene (DBT/Prange 0.49 - 0.58) recommend a siliciclastic source rather than carbonate and/or evaporate saline deposition. The ratios of CPIs, pristane/n-C17 and phytane/n-C18, n-alkanes (C16 to C22) against (C23 to C33), Ts/Tm, C30diahopane/C30hopane, methylnaphthalene, dimethyl naphthalene and trimethyl naphthalene indicated that the oils analysed are mature except the B Field oil being slightly less mature than the A, H (east) and H (west) Fields oils

Cutting samples (n = 150) and Core samples (n = 6) from the Taouratine, Dembaba, Assedjefar Marar, Awaynat Wanin, Tanezzuft and Mamuniyat Formations ( Jurassic to Ordovician), derived from wells (A-3, B-1, H-1 and H-15), locate in the A, B and H fields, present in Murzuq Basin were analysed. Rock-Eval Pyrolysis, Total Organic Carbon and specific Aromatic Molecular Biomarker (by the use of chromatography- mass spectrometry GC-MS) as geochemical parameters implemented to investigate their Lithology, kerogen type, organic matter (OM) richness and maturity evaluation. Such Formations are fair to very good quantity of organic matter passing in the course of excellent source rocks, have average of organic carbon richness (TOC) value ranged between 0.2% to 16.7% with one anomalously rich sample at 666m (well H-1) where a dark grey shale has a TOC content of 46.1% and high potential yield over 90000 ppm. The studied rocks are ranged from immature to mature of hydrogen index (HI) ranged between 24 - 302 mg HC/g TOC versus pyrolysis Tmax, with dominance of kerogen II/III Type, resulted based on HI versus oxygen index (OI), ranged from 3 to 161 mg CO2/g TOC. The Tmax , spore colouration (SCI) and Vitrinite Reflectance (% Ro) as maturity parameters ranged among 425 - 445, 5 - 8.5 and 0.35 - 3 respectively.

Aromatic hydrocarbon ratios by use of gas chromatography - mass spectrometry pointed to two levels of thermal maturity, where the high level of thermal maturity recorded in lower Silurian, whereas the less maturity was from other formations

The present research was implemented to analyses the seedling tolerance of three species Eucalyptus gomphocephala DC (Myrtaceae) (common name 'Tuart'), Eucalyptus marginata Sm. (common name 'Jarrah') and Corymbia calophylla (Lindl.) K.D. Hill & J. A. S. Johnson (common name 'Marri') to soil-induced stressor, namely soil alkalinity (limestone). Seeds germinated in shallow trays filled with white sand in a naturally lit glasshouse (control treatment). A liming treatment was conducted with 20% w/w crushed and sifted Tomala limestone adds to potting mix to increase soil pH. The experiment was conducted over 82 days. E. gomphocephala is restricted soils overlying limestone on study area and according to total seedling dry weight data and calculated relative growth rates coped best in a limestone-enriched soil. However, when examining all the growth and physiological data collected C. calophylla appeared to be the middling tolerant, with no significant difference in leaf allocation or leaf water loss between the well-watered controls and the limestone-enriched treatments whereas the E. marginata was the least tolerant with a 14% reduction in stomatal conductance. 

Research was conducted at Curtin University (Western Australia) to assess the seedling tolerance of three species Eucalyptus, gomphocephala DC (Myrtaceae) (common name ‘Tuart’), Eucalyptus marginata Sm. (common name ‘Jarrah’) and Corymbia calophylla (Lindl.) K.D. Hill & J. A. S. Johnson (common name ‘Marri’) to soil-induced stressor, namely water loggings (flooding). Flooding treatment was achieved by filling the tubs with water, approximately 1 cm above the soil surface and control treatment had the same method except with drainage holes. Study assessment was attained by statistical change in seedling growth, leaf allocation and leaf physiology after 70 days of seed germination. Tolerance was assessed by measuring changes in seedling growth, leaf allocation and leaf physiology after 70-80 days. C. calophylla was the most tolerant to prolonged waterlogging (80% survival, no difference in transpiration rates); E. marginata was the least tolerant (10% survival, 95% decrease in transpiration rate). E. marginata was the least tolerant to the three soil stresses. E. marginata prefers habitats that are not excessively wet on well-drained soils. C. calophylla was the most tolerant, occurring and tolerating wet, well-drained soils and thus demonstrated better physiological responses of three prominent studied eucalypts to soil-induced stresses provides us with invaluable knowledge for rehabilitating and restoring urban bush land.tolerance to prolong waterlogging. Knowing the seedling growth and

The present paper involves a detailed comparison between the salt tolerance and physiological responseof three eucalypt species occurring within the Swan Coastal Plain, Western Australia. Eucalyptus gomphocephala DC (Myrtaceae) (common name ‘Tuart’) is restricted to the calcareous (limestone), brown or yellow sand of the coastal Spearwood dunes. Eucalyptus marginata Sm. (common name ‘Jarrah’) is a small tree on the porous, well-drained sandy soils of the Bassendean dunes Plain, and a much larger tree on the Darling Range. Corymbia calophylla (Lindl.) K.D. Hill & J. A. S. Johnson (common name ‘Marri’), and has a similar distribution to that of Jarrah, but is more common on wetter, well drained soils. This investigate implemented to find out the seedling tolerance of these three species to soil-induced stressor, namely salinity via addition of sodium chloride solution. Tolerance assessment measured changes in seedling growth, leaf allocation and leaf physiology after 70-80 days. Neither E. marginata and C. calophylla could tolerate the highest salinity (0.25 M NaCl solutions) with 9-13% survival, although E. marginata was clearly the least tolerant with 52% reduction in relative growth rate and a 88% in transpiration rates. E. gomphocephala was the most tolerant to salt stress in terms of survival and growth parameters. 

Cutting samples (n = 93) from the Sirte, Tagrifet, Rakb, Rachmat, Bahi Formations of Upper Cretaceous and Nubian Formation (Lower Cretaceous) derived from eleven wells (6C1-59, 6J1-59, 6R1-59, KK1-65, OO2-65, M1-51, KK1-65, B-96, B-95, B-99, E1-NC-59) locate in the Amal, Gialo, Nafoora, and Sarir Fields present in East Sirte Basin were analysed in the aim of their organic geochemical evaluation. A bulk geochemical parameters and evaluation of specific biomarkers by chromatography-mass spectrometry (GC-MS) implemented to find out a diversity of interbedded non-marine lithofacies including sandstones, siltstones, shales and conglomerates. Such rocks are good source and contain fair to good contented of organic matter passing in the course of very good, in which the excellent source rocks have organic carbon richness (TOC) reached to 5.16 wt%. The studied samples are ranged from gas to oil-prone organic matter (OM) of hydrogen index (HI) ranged between 115 - 702 mg HC/g TOC, related with gas prone (OM) of (HI) <150 and most beds contain oil-prone organic matter of (HI) > 300, associated with oxygen index (OI): 3 - 309 mg CO2/g TOC indicate that organic matter is dominated by Type II/III kerogen. The maturity of these source rocks is variations ranges from mature to post-mature-oil window in the Sirte and Rachmat Formations, as inferred from the production index (PI: 0.07 - 1.55) and Tmax and Ro% data (Tmax: 425 - 440/Ro%: 0.46 - 1.38) and early to mid-stage maturities for the other formations. Low PI in some samples seems to imply that the most of the hydrocarbons have expelled and migrated from the rocks. Biomarker ratios of individual hydrocarbons in rock extracts (n = 21), were also used in order to investigate the samples’ thermal maturity and palaeo depositional conditions. Pristine/Phytane ratios of 0.65 - 1.25 and dibenzothiophene to phenanthrene (DBT/P) ratios of 0.04 - 0.47 indicated Anoxic and suboxic conditions of depositional source rock. The origin of OM of the studied samples attributed to a marine algal source as indicated from the dominated by the C27 and co-dominant C28 homologues sterane in molecular composition distributions. The marine shale and carbonate lithofacies of rock samples were also indicated by high C19TT/C23TT ratio and low relative abundance of C24TeT/C23TT, consistent with their interpreted marine affinity. An organic geochemical evaluation pointed out that the Sirte Shale formation (Campanian/Turonian) is the main source rock in this petroleum area. 

Tricyclic terpanes to hopanes Ratios calculated from individual biomarkers to delineate their distribution, identifications, mixing ratios and biological precursor in a suite of crude oils (n = 24) from the East Sirt Basin. Geochemical application of Tricyclic terpane and Hopane biomarkers is divided studied oils into five groups (I, II, III, IV and V) based on the different ratios between Tricyclic terpanes to hopanes. Percentages of C23 Tricyclic terpanes/17α (H), 21β(H)-hopanes (C30αβ) and C28 Tricyclic terpane/17α (H), 21β (H)-30 hopanes (C31) have divided crude oils into 2 main individual groups in addition to 3 mixed groups. Group I, characterized by the dominance and extension of the tricycle terpane series (≈ C45 Tricyclic terpane). Group V, distinguished with the dominance of 17α (H), 21β (H) hopanes series. Groups II, contained a domination Tricyclic terpanes and hopanes, considered as a mixed group. The group III demonstrated equivalent ratios of Tricyclic terpanes to hopanes. The Group IV revealed a reduced amount of Tricyclic terpanes with enrich of hopanes. Tricyclic terpanes derived from tricyclohexaprenol precursors and attributed to a marine depositional environment and algal matter. Hopanes in obtained from bacteriohopane polyols and aminopolyols and distinguished to a depositional bacterial environment.

The present paper involves a detailed evaluation of specific steroid biomarkers by gas chromatography– mass spectrometry (GC–MS) and GC-metastable reaction monitoring (MRM) analyses of several crude oils and source rocks from the East Sirte Basin. 24-Norcholestanes, dinosteranes, 4a-methyl-24-ethylcholestanes and triaromatic steroids have been identified in both source-rocks and crude oils of the East Sirte Basin. Diatoms, dinoflagellates (including those potentially associated with corals) and/or their direct ancestors are amongst the proposed sources of these biomarkers. These biomarker parameters have been used to establish a Mesozoic oil–source correlation of the East Sirte Basin. Hydropyrolysis of an extant coral extract revealed a similar distribution (although immature) of dinosteranes and 4a-methyl-24-ethylcholestanes also observed in the Sirte oils and source-rocks. This is consistent with the presence of dinoflagellates present during the deposition of the Mesozoic aged East Sirte Basin Formations. A good data correlation for the rock extracts revealed a similar distribution of 3,24-dimethyl triaromatic steroids, 3-methyl-24-ethylcholestanes, 4-methyl-24-ethylcholestanes and 2-methyl-24-ethylcholestanes observed in one of the oil families and associated source-rocks for the East Sirte Basin.

Biomarker ratios, together with stable carbon (d13C) and hydrogen (dD) isotopic compositions of individual hydrocarbons have been determined in a suite of crude oils (n = 24) from the East Sirte Basin to delineate their sources and respective thermal maturity. The crude oil samples are divided into two main families (A and B) based on differences in source inputs and thermal maturity. Using source specific parameters including pristane/phytane (Pr/Ph), hopane/sterane, dibenzothiophene/ phenanthrene (DBT/P), Pr/n-C17 and Ph/n-Cl8 ratios and the distributions of tricyclic and tetracyclic terpanes, family B oils are ascribed a marine source rock deposited under sub-oxic conditions, while family A oils have a more terrigenous source affinity. This genetic classification is supported by the stable carbon isotopic compositions (d13C) of the n-alkanes. Using biomarker maturity parameters such as the abundance of Pr and Ph relative to n-alkanes and the distribution of sterane and hopane isomers, family A oils are shown to be more thermally mature than family B oils. The contrasting maturity of the two families is supported by differences between the stable hydrogen isotopic compositions (dD) of Pr and Ph and the n-alkanes, as well as the d13C values of n-alkanes in their respective oils.