Organic Geochemistry and Depositional Environment of the Oltu

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Organic Geochemistry and Depositional Environment of the Oltu Gemstone (Coal) in the Erzurum Area, NE Anatolia, Turkey Reyhan Kara-Gülbay, Sadettin Korkmaz, Gülten Yaylali-Abanuz, and Mert Samet Erdo#an Energy Fuels, Just Accepted Manuscript • Publication Date (Web): 10 Jan 2018 Downloaded from http://pubs.acs.org on January 10, 2018

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Organic Geochemistry and Depositional Environment of the Oltu Gemstone (Coal) in the Erzurum Area, NE Anatolia, Turkey Reyhan Kara-Gülbay*, Sadettin Korkmaz, Gülten Yaylalı-Abanuz and M. Samet Erdoğan Karadeniz Technical University, Department of Geological Engineering, 61080, Trabzon, Turkey

ABSTRACT: The Oltu Gemstone is located in the north of Oltu town (Erzurum-NE Turkey) city is a low rank coal. The Oltu Gemstone occurs as lenticular forms with thickness not exceeding cm size and lateral continuity of a few meters within the Liassic-Lower Malm Olurdere Formation consisting chiefly of claystone, sandstone and volcanics. Coals that are operated as Oltu Gemstone are represented by very high TOC (67.39-78.56% wt.), high hydrogen index (HI) values (314-379 mgHC/gTOC) and very low oxygen index (OI) values (1-3 mgCO2/gTOC). Low Pr/Ph ratios indicate that coals were prevented from oxidation and deposited under anoxic conditions. In Oltu Gemstone samples C29 dominates over C27 and C28 steranes. In general, high (C19+C20)/C23 tricyclic terpane, low Ts/(Ts+Tm), diasterane/sterane and C31R/C30 hopane ratios were recorded. C29 MA steroids dominate with respect to others and C29/(C28+C29) MA ratio is mostly high. DBT/P ratio of Oltu Gemstone samples has low values. Tmax values of Oltu Gemstone samples (between 416-436 ºC) reflect immature-early mature character. 22S/(22R+22S) homohopane, 20S/(20R+20S) and ββ/(αα+ββ) sterane ratios and low moretane/hopane ratios, relatively high C28-TA/(C29-MA+C28-TA), MA(I)/MA(I+II), TA(I)/TA(I+II), MPI-3 (β/α MP) and MDR ratios indicate early mature character for the Oltu Gemstone samples. Keywords: Oltu Gemstone, coal, pyrolysis, biomarker, maturity, depositional environment

*Corresponding author. Tel.: +90 462 377 2073; fax: +90 462 325 7405. E-mail address: [email protected] (R. Kara-Gulbay)

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1. INTRODUCTION The Oltu Gemstone occuring on southern flanks of Dutlu Mountain at north of Oltu town, 124 km NE of Erzurum city, Eastern Turkey, has been exploited from galleries with primitive methods (Figure 1). This gemstone, so called as “Oltu taşı” in Turkish is a semi-precious stone. In the literature it is also

known as “Black Amber”, “Gagat”, “Jayet” and “Jet”.(1, 2) Although the precise time when the Oltu Gemstone was first exploited and processed in the region is not known, it is thought that it was started to be mined by the end of 18th century.(2) The Oltu Gemstone is exploited from approximately 300 galleries having 70-80 cm opening at southern flanks of Dutlu Mountain. The stone is used for manufacturing bead, jeweler and ornament by goldshmidts. The Oltu Gemstone, once exploited, is subjected to several processes until it is turned into products (Figure 2). The Oltu Gemstone within the host bed has low degree of hardness. But when itis eft under subaerial condition, it progressively gets harder. Therefore it can easly shaped when it is fresh. In addition, Oltu Gemstone becomes brighter with use.(3, 4) It is generally black to dark brown and rarely gray and greenish in color.

The study area and its surroundings have been studied in detail because of having potential for Oltu Gemstone, oil and coal.(5, 6, 7, 8, 9, 10, 11, 12) There are also studies focusing on the history of Oltu Gemstone in the region and ornaments and jewelry manufactured using Oltu Gemstone.(1, 2, 3, 4, 13, 14) Göymen (15) stated that Oltu Gemstone shows a cellular texture and organic textures in coalified cells were replaced by colloidal silica and carbonate minerals. According to Göymen (15), the hardness of Oltu Gemstone which is easily processed and polished and used as an ornament is attributed to its unique cell structure which is filled by amorphous and cryptocrystalline quartz. Karayiğit (8) showed that Oltu Gemstone has very low ash (2.33%) and high volatile material (63.86%) contents. Total sulfur and calorific (gross calorific value) values of Oltu Gemstone were measured as 1.80% and 7703 kcal/kg, respectively. Low reflection values of textinite and

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corpohuminite (0.23 and 0.30 %Rr, respectively) indicate high volatile content and low-rank coal.(8) Toprak (11) measured reflection values of liptinite macerals and obtained in the range of 0.45-0.49%. In association with compression regime, the study area was uplifted during the upper Cretaceous-Oligocene time and subjected to erosion (6, 16) During the beginning of Oligocene, intermountain basins surrounded by thrust faults were formed in which terrestrial clastics were deposited. The Oltu-Narman Tertiary basin is one of these basins (6, 16). Compressional regime in the region was continued throughout Tertiary. Low maturity of Liassic-lower Malm Oltu Gemstone (coal) can be attributed to uplifting of the region under compression during the upper Cretaceous and cooling of the system. Although sequences related to Tertiary basins were formed in the region, intermountain character of these basins resulted in local basin formation (Figure 1) and Oltu Gemstone-bearing unit was not subjected to a burial effect due to Tertiary sequences. Therefore, low maturity of Oltu Gemstone may be ascribed to insufficient burial depth. The origin of Oltu Gemstone is discussed in several studies and it is regarded as intensely metamorphosed coal or anthracite.(17) Karayiğit (8), however, states that Oltu Gemstone is a low-rank coal. Although Oltu Gemstone has been the subject of several studies, its organic geochemical properties were not investigated. The aim of this work is to determine depositional environment of Oltu Gemstone, its biomarker distributions (saturated, aromatic and polar), organic geochemical characteristics, organic matter type, maturity and specify the contribution of geochemical characteristics to physical properties of this stone.

2. MATERIAL AND METHODS In this study, Oltu Gemstone, coal and silty claystone samples were collected from different levels in galleries opened at southern flanks of the Dutlu Mountain 3.5 km from the Dutlu village (sample location; x: 40.672736; y: 42.047236; z: 2050 m). In this study totally 6 Oltu Gemstone samples, one sample from coal occurrences and another sample from silty claystones were studied investigated by pyrolysis/TOC analysis. GC and GC-MS analyses were conducted on 4 selected Oltu Gemstone samples.


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Rock-Eval pyrolysis and TOC analyses were made using a Rock-Eval 6 instrument equipped with a TOC module. Samples were heated from 300°C (holding time 3 min) to 650°C at 25°C/min. The crushed rock was heated from 400°C (holding time 3 min) to 850°C (holding time 5 min) at 25°C/min for oxidation. Following Rock-Eval and TOC analyses, gas chromatography (GC) (bulk extract) and gas chromatography-mass spectrometry (GC-MS) (saturated hydrocarbons - sterane and terpane/aromatic hydrocarbons - monoaromatic and triaromatic steroids, phenantrene and methylphenantrenes, dibenzotiophene, and methyl- dibenzotiophenes) analyses were carried out on extracts from gemstone samples. The C15+ soluble organic matter (SOM) was isolated following Soxhlet extraction (40 hr) of the powdered rock with dichloromethane (CH2Cl2). Whole coal (Oltu Gemstone) extracts were analyzed using a Varian 3400 gas chromatograph equipped with flame photometric (FPD) and flame ionization detectors (FID). A fused capillary column (60 m, 0.20 mm i.d.) coated with cross-linked dimethylpolysiloxane (J&W, 0.25 µm film thickness) was used. The oven temperature was increased from 40ºC (holding time 8 min) to 270ºC (holding time 60 min) at 4ºC/min. Gemstone extracts were de-asphaltened using n-pentane and fractioned by thin-layer chromatography (MK-Iatroscan). n-hexane, toluene, and methanol were used for extract separation into saturated hydrocarbons, aromatic hydrocarbons, and NSO fractions, respectively. GC-MS analyses were conducted on the saturated and aromatic fractions using an Agilent 5975C quadruple mass spectrometer coupled to a 7890A gas chromatograph and a 7683B automatic liquid sampler. The gas chromatograph was equipped with an HP-1MS fused silica capillary column of 60 m length, 0.25 mm i.d., and 0.25 µm film thickness. Helium was used as the carrier gas. The oven temperature was from 50ºC (holding time 10 min) to 200ºC (holding time 15 min) at 10ºC/min, to 250ºC (holding time 24 min) at 5ºC/min and then to 280ºC (holding time 24 min) at 2ºC/min. Finally, the oven temperature was increased to 290ºC (time 40 min) at 1ºC/min. The mass spectrometer was operated at EI mode with ionization energy of 70 eV and a source temperature of 300ºC. The biomarker contents were determined using single-ion recordingly at m/z 191 for tri-, tetra- and pentacyclic triterpanes, at m/z 217 for steranes and rearranged steranes, at m/z 253 for monoaromatic steranes, at m/z 231 for triaromatic steranes, at 178 and 192 for phenantrene and methyl-phenantrene, and at m/z 187 and 198 4 ACS Paragon Plus Environment

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for dibenzotiophene and methyl-dibenzotiophenes. Compounds were categorized by their retention time and elution order matching. Rock Eval/TOC, GC, and GC-MS analyses were made at the Geochemistry Laboratories of Turkish Petroleum (TP).

3. GEOLOGICAL SETTING Permo-Carboniferous dacite and rhyodacite occur at the basement of study area and these volcanic rocks were cut by granite porphyry stocks and dykes (Figure 3).(7) They are unconformably overlain by Liassic-Lower Malm claystone, sandstone and volcanics

having thin coal bands and Oltu

Gemstone occurrences. The sequence continues with Upper Malm-Lower Cretaceous limestone and sandy cherty limestones. During the Early-Late Cretaceous time, sandstone-siltstone-limestone-marl series were deposited. In the Late Cretaceous, the sequence consisting of sandstone, tuffite, limestone, clayey limestone, marl and claystone laid over the underlying unit. Cretaceous units are unconformably overlain by Eocene aged claystone, conglomerate, sandstone and tuffite which are also unconformably covered by Oligocene aged conglomerate-sandstone-siltstone sequence. The Tertiary sequence continues upwards with Upper Oligocene basalt, Pliocene gypsum interbedded marl and claystones and is ended up with Plio-Quaternary basalts. The Oltu Gemstone occurences under investigation are found in Liassic-Early Malm aged Olurdere Formation (Figure 3). The Olurdere Formation starts at the bottom with sandstone and clayey limestone interbedded claystone and continues upward with diabase, basalt, pyroclastics and ends up with limestone, marl, conglomerate, claystone interlayered thin-medium-thick bedded sandstone. In samples collected from lower levels of the unit Involutina sp. (gr. liassica), Involutina sp., Reolisaccus sp., Radiolarian, Calliphlloceras sp., Anthozoa, Tabulozoan, Pelycypoda, Crinoid stems and Echinoid spines which yield Liassic age were determined.(18) In samples taken from upper levels of the formation Trocholina cf. conica (Schlumberger), Protopeneroplis cf. striata Weinschenk, Pseudocyclammina sp. (gr. lituus), Pseudocyclammina sp., Textulariidae, Lituolidae, Valvulinidae, Algae and Mollusca fossils which yield Upper Dogger-Lower Malm age were determined.(7) Based on this fossil assemblage the Olurdere Formation is dated as Liassic-Early Malm. Considering its 5 ACS Paragon Plus Environment

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lithological characteristics, fossil content and sedimentary structure properties, Bozkuş (7) suggests that the unit must have been deposited in an environment changing from shallow marine to deep shelf where volcanism was effective. The presence of thin coal bands and coalified plant levels within the unit reflects that the environment occasionally changed to swamps. Particularly in claystone and siltstones and partly in sandstone levels of the Olurdere Formation there are Oltu Gemstone occurrences with thickness not exceeding a few cm (max. 50 cm) and lateral continuity up to a few meters (Figure 4). Unit also hosts Oltu Gemstone as small lenses of a few cm size (Figure 4 b,c,d) and coal levels with no ornament character (Figure 4e). Fossilized tree trunks and Oltu Gemstone formations around them are also found in this unit (Figure 4f).

4. RESULTS 4.1. TOC and Rock-Eval pyrolysis analysis TOC values of Oltu Gemstone samples are high changing from 67.39 to 78.56% (Table 1). HI values of samples are 314-379 mgHC/gTOC and oxygen index values are very low (1-3 mgCO2/gTOC). S1, S2 and Potential Yield (PY) (S1+S2) values of the Oltu Gemstone samples very high (221.05-309.05 mgHC/gTOC) (Table 1). The Oltu Gemstone (coal) samples have very high pyrolysable carbon content. Oltu stone is characterized by quite high TOC values, although the TOC values are low in low maturity coal such as Oltu stone. (19) Oltu Gemstone sample collected around a tree fossil within the Olurdere Formation yielded 30.25% TOC content and very high HI value (422 mgHC/gTOC). OI value of this sample is very low (5 mgCO2/gTOC). Organic matter content of sample (OE-4) from coal occurrence (with no ornament character) is lower than that of Oltu Gemstone and TOC value is found 48.81%. HI value (199 mgHC/gTOC) of this sample is lower than that of Oltu Gemstone but OI value is higher (8 mgCO2/gTOC). Sample collected from dark gray silty claystone that hosts occurrences has TOC value of 5.32% and HI value of 291 mgHC/gTOC. Tmax values of Oltu Gemstone, coal and silty claystone samples are between 416-436 °C (Table 1).

4.2. Molecular composition


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4.2.1. n-alkanes and isoprenoids In bulk extract gas chromatograms of Oltu Gemstone samples n-alkanes and isoprenoids were recorded in trace amounts while other components (aromatic, polar) are in high abundance (Figure 5). Pr/Ph ratios ranges from 0.33 to 1.33. Pr/n-C17 and Ph/n-C18 ratios range from 0.20-4.50 and from 0.49 to 1.88, respectively (Table 2). 4.2.2. Steranes and terpanes In m/z 217 mass chromatograms of Oltu Gemstone samples, pregnanes were recorded in high abundance. Diasteranes are in low abundance and steranes dominate over diasteranes. In all samples, there is a sterane distribution in which C29 dominates over others. C27 and C28 steranes are almost in same abundance and except for sample OE-2, C27 is recorded in high abundance (Figure 6 a-d; Table 3). In general, n-steranes are dominant and for only sample OE-1 iso-sterane dominates over others (Figure 6a-d; Table 3). In m/z 191 mass chromatograms, for samples OE-1 and OE-2, hopanes were recorded in higher abundance with respect to tricyclic terpanes. In samples OE-4 and OE-5, there is a terpane distribution in which tricyclic terpanes are recorded in higher abundance with respect to hopanes. C19 and C20 were recorded in high abundance and (C19+C20)/C23 tricyclic terpane ratios of Oltu Gemstone samples are 11.02-1.20 (Fig 6. e-h, Table 3). For all samples, Tm dominates over Ts. For samples OE-1 and OE-2, C30 hopane is dominant with respect to C29 while, for samples OE-4 and OE-5, C29 norhopane dominates over hopane. For sample OE-1, C29Ts and C30 diahopane (C30*) were recorded in significant quantity. For other samples, C29Ts is recorded in trace amount, while C30* is low or trace quantities. For samples OE-4 and OE-5, C25 and C26 tricyclic terpane were recorded; C25 for OE-1 and C26 tricyclic terpane for OE-2 are dominant. There is a homohopane distribution characterized by C31 dominance and decreasing abundance towards the high-carbon number homologs and 22S epimers were recorded in much quantity with respect to 22R epimers (Figure 6e-h, Table 3). 4.2.3. Aromatic hydrocarbons and polar compounds 7 ACS Paragon Plus Environment

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In m/z 253 mass chromatograms of Oltu Gemstone, C27 monoaromatic steroids were recorded either in trace amount or were not recorded at all (Figure 7a-d). Except for sample OE-1 in which C28 MA steroids are dominant, C29 MA steroids in other samples are much dominant with respect to others. For samples OE-1 and OE-2, C21 and C22 monoaromatic steroids [MA(I)] were recorded in low abundance (trace amounts) with respect to C27, C28 and C29 steroids [MA(II)]. In samples OE-4 and OE-5, C21 and C22 monoaromatic steroids were found in significant quantity (Figure 7a-d). MA(I)/MA(I+II) ratios of Oltu Gemstone samples are between 0.03 and 0.21 (Table 3). For samples OE-4 and OE-5, C20, C21 monoaromatic steroids, defined as TA(I), dominate over C26, C27, C28 monoaromatic steroids, defined as TA(II), while for samples OE-1 and OE-2 TA(II) is much dominant (Figure 7e-h, Table 3). For all Oltu Gemstone samples, phenantrene and methyl-phenantrene distributions are similar (Figure 8a-d). Phenantrenes were recorded in increasing quantity with respect to methyl-phenantrenes. For samples OE-1 and OE-2, 9-MP is found to be dominant with respect to others. In samples OE-4 and OE-5, 2-MP and 9-MP are the dominant components. Dibenzothiophenes (DBT) dominate over methyl-dibenzothiophene (MDBT) (Figure 8f-h). 2-MDBT was recorded in increasing quantity with respect to others. 4-MDBT dominates over 1-MDBT and MDR and MDR' ratios were estimated quite high (Table 3). Phenanthrene that was recorded in m/z 178 mass chromatograms dominates over dibenzothiophene that was found in all m/z 184 mass chromatograms and DBT/P ratio is very low (ranging between 0.12 and 0.33) (Table 3).

5. DISCUSSION 5.1. Depositional environment and type of organic matter Karayiğit (13) identified mainly textinite and corpohuminite, minor amounts of resinite and liptodetrinite in petrographic determinations on Oltu Gemstone samples. Toprak (11) has revealed that Oltu Gemstone is petrographically rich in suberinite and contains spores, resinite and huminite in lesser amounts. According to the results of pyrolysis analysis, Oltu Gemstone samples with HI values of 314379 mg HC/g rock are plotted in Type II kerogen field (Figure 9a,b). Although Oltu Gemstones are 8 ACS Paragon Plus Environment

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coal, they have high HI values and very low OI values (1-3 mg CO2/g TOC) which indicate that organic matter was preserved from oxidation. Oltu Gemstone occurrence around the fossilized tree trunks within the Jurassic sequence reflects the role of resin-rich trees in formation of Oltu Gemstones. The use of this coal (Oltu Gemstone) as a gemstone is associated with this resin content. As indicated by biomarker data, Oltu Gemstones are represented chiefly by terrestrial organic matter. Type II kerogen is derived mainly from marine organic matter. However, Type I and Type II kerogen mixtures may also end up with Type II kerogen. Similarly, in Oltu Gemstones, terrestrial organic matter (Type III) and liptinite (Type I) deriving essentially from terrestrial organic matter end up with Type II kerogen. Coal occurrences without gemstone character that accompany the Oltu Gemstone have very low HI index values which can be explained by the absence of liptinite components (particularly resin). Pr/Ph ratios of Oltu Gemstones are in the range of 0.33 and 1.33 (Table 2) indicating deposition under anoxic conditions. The dominance of C29 sterane is attributed to input of terrestrial organic matter.(20, 21, 22) (Figure 10f) The C19 and C20 tricyclic terpane is associated with terrestrial organic matter input and high (C19+C20)/C23 tricyclic terpane ratio reflects terrestrial organic matter contribution.(23) This ratio for the Oltu Gemstones were calculated as being between 1.20 and 11.02, which are considered high. These high values also point the dominant terrestrial organic matter input. A high C35S/C34S homohopane ratio indicates anoxic conditions and high ratios (>0.8) have been determined for petroleum derived from carbonate rocks in general.(24) C35S/C34S ratios of Oltu Gemstone samples were calculated as being between 0.56 and 1.1.03, indicating anoxic sedimentary conditions and carbonate mineral content (Figure 10 a). The C29/C30 hopane ratio increases with increasing carbonate content (25, 26, 27) is high for samples OE-4 and OE-5 and very low for samples OE-1 and OE-2 (Figure 10a). This difference is probably associated with replacement of organic textures in Oltu Gemstones by carbonate minerals as indicated by Göymen (15) and inhomogeneous distribution of carbonate minerals in veins of Oltu Gemstones. In this respect, it can be said that carbonate minerals in veins from which OE-4 and OE-5 are sampled are probably much abundant than those in samples OE-1 and OE-2.


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C31R/C30 hopane ratio in marine source rocks is higher than that in lacustrine source rocks (C31R/C30>0.25).(31) This ratio is very low (ranging between 0.06 and 0.22) for Oltu Gemstones which are thought to be deposited in ephemeral swamps in association with marine environment according to geological data. This might be attributed to the fact that Oltu Gemstones were formed in a swamp environment and thus was preserved from marine effect during the deposition. Ts/(Ts+Tm) ratio is depend upon both maturity and lithology. It increases with increasing maturity and clay abundance.(28, 29, 30) In all Oltu Gemstone samples, Tm dominates over Ts and Ts/(Ts+Tm) ratio is very low (ranging between 0.37 and 0.12) (Table 3). Very low ash content in Oltu Gemstone samples (2.33%) (8) indicates low clay content. Diasterane/sterane ratio is high for clay-rich source rocks and increases with maturity.(26, 31) Low Ts/(Ts+Tm) and diasterane/sterane ratios of Oltu Gemstones arised from low clay content and low maturity (Figure 10b). Terrestrial organic matter and non-marine algae contain much more C29 sterol with respect to marine organic matter and marine algae.(32, 33) Monoaromatic steroids in Oltu Gemstone samples are much abundant than others (except for OE-1). C29/(C28+C29) MA ratio greater than 0.5 is indicative of terrestrial organic matter while a lower value indicates marine organic matter.(27) Based on this, values being in the range of 0.24 and 0.90 indicate that Oltu Gemstone samples, except for sample OE-1, chiefly contain terrestrial organic matter. Requejo (34) showed that DBT/P ratio in the range of 0.06 and 0.2 is typical for coals (terrestrial organic matter). Except the sample OE-1 which has a DBT/P ratio of 0.33, other Oltu Gemstone samples have a DBT/P ratio lower than 0.2 ranging between 0.12 and 0.17. Although Oltu Gemstone samples contain predominantly terrestrial organic matter, their very low Pr/Ph ratios make them to fall into "lacustrine sulphate-poor (2) and "marine shale and other lacustrine (3)" on the DBT/P-Pr/Ph deposition environment diagram (Figure 10c) (35). This does not point to that Oltu Gemstones were deposited in different environments but rather they were deposited in an environment with varying redox potential (under suboxic and anoxic conditions).


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5.2. Maturity of organic matter %Rr values were determined as 0.23 and 0.30% for textinite and corpohuminite, respectively (13). Toprak (11) performed reflectance measurements on liptinite macerals of Oltu Gemstone and found Rmax values between 0.45 and 0.49%. Tmax values of Oltu Gemstone, coal and silty claystone samples from the Jurassic sequence are between 416 and 436°C (Table 1) indicating immature-early mature character. Tmax values between 416-436°C correspond to 0.4-0.6 %Ro values (36) and based on this data and reflection values obtained from previous studies, Oltu Gemstone and accompanying coals are in the lignite - subbituminous C-A. Biologically existing 22R forms of homohopanes transform to 22S epimers with increasing maturity and, attain equilibrium during early mature stage (about Ro 0.55%). Hopanes can also be derived from decarboxylation of hopanoic acids.(37) Ratios at equilibrium are 55-60% S and 40-45% R.(23, 26) 22S/(22S+22R) ratio (for C32) of Oltu Gemstones are in the range of 0.56-0.62 indicating that equilibrium is attained for homohopane isomerization. Biologically existing 20R ααα forms of steranes transform to 20S forms with increasing maturity and attain equilibrium with ratios of 55%S and 45%R at a maturity level of about 0.8% Ro.(38) 20S/(20S+20R) ratios of Oltu Gemstone samples (for C29) are found in the range of 0.24-0.33. Biologically produced αα sterane forms transform to ββ forms with increasing maturity and attain equilibrium with values of 70%αα and 30% ββ.(23, 26) ββ/(ββ+αα) sterane ratios of Oltu Gemstones are in the range between 0.16 and 0.39.

22S/(22S+22R) homohopane, 20S/(20S+20R) and

ββ/(ββ+αα) sterane ratios indicate that Oltu Gemstone samples are low - mature (early mature) (Figure 10d,e). Moretanes are less stable than 17α(H) hopanes and it is thought that moretane is transformed to hopanes with increasing maturity.(39, 40) Kara Gülbay and Korkmaz (41) showed that there is a strong negative correlation between moretane/hopane and 20S/(20R+20S) sterane 22S/(22R+22S) homohopane ratios. Moretane/hopane ratio drops with maturity and any value higher than 0.15 corresponds to a maturity lower than 0.6% Ro.(26) Moretane/hopane ratios of Oltu Gemstone samples are in the range of 0.06-0.23 reflecting early mature level. Hussler et al. (42) showed the presence of monoaromatic steroids in sterane-bearing immature sediments and concluded that monoaromatic steroids can develop under slightly diagenetic conditions.


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On the other hand, El Gayar (43) could not record triaromatic steroids at significant levels in recent sediments and this may indicate that they were formed following diagenesis stages. Aromaticity increases in crude oil and sediments with increasing maturity and monoaromatic steroids (MA) transform to triaromatic steroids (TA).(44, 45, 46) With increasing maturity C28-TA/(C29-MA+C28TA) ratio increases from 0 to 100% and it is used to determine immature-mature interval.(23, 31) C28TA/(C29-MA+C28-TA) ratios of Oltu Gemstone samples calculated as being in the range between 0.01 and 0.40. MA(I)/MA(I+II) ratio of oil and source rocks increases with thermal maturity and it is descriptive for early mature-late mature interval.(44, 45) With thermal maturity this ratio increases from 0 to 100%.(27) MA(I)/MA(I+II) ratios of Oltu Gemstone samples are computed as being in the range of 0.03-0.21 indicating that Oltu Gemstone samples are in the immature-early mature stage. According to Beach et al. (47), TA(I)/TA(I+II) ratio increases with increasing maturity which is related to preferential degradation of long-chain triaromatic homologs rather than transformation of long-chains to short-chains. This parameter is descriptive for mature and late mature stages.(27) TA(I)/TA(I+II) values of Oltu Gemstone samples are between 0.04 and 0.65 representing immaturemature (peak oil generation) range. Alkylphenantrenes are commonly used as a maturity parameter.(48) Radke (49) classified the oils into three maturity groups using MPI-3 value [the ratio of 2-MP and 3MP (β-isomers) isomers that are thermodynamically more stable than the 1-MP and 9- MP (α-isomers) isomers].(50) The oils with MPI-3 value greater than 1 are mature while those with MPI-3 value between 0.8-1.0 are moderately mature and those with MPI-3 value less than 0.8 are classified immature.(49) Based on their MPI-3 values, samples OE-4 and OE-5 (0.92 and 0.95) are moderately mature while samples OE-1 and OE-2 (0.59 and 0.70) are immature. Each alkylbenzothiophene ratio changes with respect to maturity and methylbenzothiophene ratios (MDR and MDR') are based on decrease in 1-MDBT with increasing maturity and relative increase in 4-MDBT which is thermodynamically more stable. (51, 52) For Oltu Gemstone samples, 4-MDBT dominates over 1MDBT and MDR is computed as being the range from 2.8 and 4.69.


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6. CONCLUSION Liassic-Lower Malm Olurdere Formation in Erzurum city, Eastern Turkey, hosts Oltu Gemstone coals (used for making ornamental stone) having a few meters of lateral continuity and 50 cm of maximum thickness. The same formation also contains coal occurrences with no ornament nature that are associated with Oltu Gemstone. The Oltu Gemstone samples have very high TOC contents, high HI values and very low OI values. Coal samples are represented by lower TOC contents and HI values with respect to Oltu Gemstone. Oltu Gemstone samples were defined as being Type II kerogen. Oltu Gemstone occurrences around fossilized tree trunks within the unit reflect contribution of resin-rich trees in formation of Oltu Gemstones. Although biomarker data show significant terrestrial organic matter input, high HI values and Type II kerogen character are as a result of liptinite components (suberinite, resinite and sporinite) originating from terrestrial organic matter input. Coal lenses with no ornament nature have low HI values and organic matter content different from the Oltu Gemstones which can be attributed to the fact that coals contain resin-free terrestrial organic matter. Tmax values (416-436°C) of silty claystone, coal and Oltu Gemstone samples indicate immatureearly mature character and coal rank of lignite - subbituminous C-A. Maturity parameters obtained from saturated and aromatic biomarker data also reflect immature-early mature character for the Oltu Gemstone coals. The lower maturity value of the Oltu stones in the Lower Jurassic Lower Cretaceous unit is related to the uplifting of the region under compression during the upper Cretaceous and later, and the erosion of the region. Oltu Gemstone coals occur in a Liassic-Lower Malm aged unit that was deposited in an environment changing from shallow marine to deep shelf conditions where volcanism was effective and coal occurrences were formed by deposition of organic matter of mainly terrestrial type under anoxic conditions in an environment which occasionally changed to ephemeral swamps where resinrich trees supplied resin source.

ACKNOWLEDGEMENTS


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Dutlu village headman Ekrem Narşap and villagers exploiting Oltu Gemstone from galleries supported this study in sampling. The analyses were carried out in the TP (Turkish Petroleum). The authors thank these individuals and organizations. The authors thank reviewer H. Orhan (Selçuk University), four anonymous reviewers and associate editor P. Hatcher who provided useful comments and improved the manuscript.

REFERENCES 1. Ethem, M, Y., 1990. Precious and semi-precious stones from A to Z. Mars Printing Press, Ankara (in Turkish). 2. Alparslan, E., 2010. Oltu gemstone, gold and silver by using were produced examining of samples cuff-link and tie pin. ZfWT 2 (in Turkish with English abstract). 3. Gündoğdu, H., Gedik, Đ., 1985. Oltu Gemstone mining in Erzurum. The Bulletin of Science, Unitiy and Success 43, 7-12. 4. Parlak. T., 1989. The Gemstone from source to showcase. Erzurum Atatürk University Press, Erzurum. 5. Gedik,. A., 1985. Geology and petroleum possibilities of Tekman (Erzurum) basin. MTA Bulletins 103-104, 1-24 (in Turkish with English abstract). 6. Bozkuş, C., 1990. Stratigraphy of northeast part of the Oltu-Narman (Kömürlü) Tertiary basin. Gological Bulletin of Turkey 33, 47-56 (in Turkish with English abstract ). 7. Bozkuş, C., 1992. Stratigraphy of the Olur (Erzurum) region. Geological Bulletin of Turkey 35, 103-109 (in Turkish with English abstract). 8. Karayiğit, A.Đ., 2007. Origin and properties of Oltu Gemstone Coal. Energy Sources, Part A 29, 1279-1284. 9. Kalkan, E., Bilici, Ö., Kolaylı, H., 2012. Evolution of Turkish black amber: A casestudy of Oltu (Erzurum), NE Turkey. International journal of Physical Sciences 7, 2387-2397.


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10. Kınacı, E.H., 2013. Mineralogical and gemmological investigation and genesis of Oltu stone (carbon black). Ms thesis, Dokuz Eylül University, Đzmir. 11. Toprak, S., 2013. Petrographical properties of a semi-precious coaly stone, Oltu gemstone, from eastern Turkey. International Journal of Coal Geology 120, 95-101. 12. Kara Gülbay, R., 2015. Organic geochemical and petrographical characteristics of coal bearing Oligo-Miocene sequence in the Oltu-Narman Basin (Erzurum), NE Turkey. International Journal of Coal Geology 149, 193-107. 13. Alparslan, E., 2009. Oltu stone working and some properties of stone works produced in the region. PhD thesis, Anakara University (in Turkish with English abstract). 14. Hatipoğlu, M., Ajo, D., Kibici, Y., Passeri, D., 2012. Natural carbon black (Oltu-stone) from Turkey: a micro-Raman study. Neues Jahrbuch für Mineralogie-Abhandlungen (Journal of Mineralogy and Geochemistry) 189, 97-101. 15. Göymen, G., 1976. About Oltu stone. Earth and Human 1, 46-47 (in Turkish). 16. Bozkuş, C., Yılmaz Ö., 1993. Tectonics of the region between Tercan (Erzincan) and Aşkale (Erzurum). Geological Bulletin of Turkey 36, 189-201 (in Turkish with English abstract). 17. Çiftçi, E., Yalçın, M. G., Yalçınalp, B., Kolaylı, H., 2004. Mineralogical and physical characterization ol the oltustone, a gemstone occuring around Oltu (Erzurum-Eastern Turkey). International Congress on Applied Mineralogy (ICAM 2004), September 19-22, Brazil. 18. Yılmaz, C., 1985. Geology of Olur (Erzurum) region. KTÜ Bulletin of Geology 4, 23-43, Trabzon (in Turkish with English abstract). 19. Hoş-Çebi, F., Korkmaz, S., 2011. The environmentally significant element contents of Eocene coals in North Anatolia, Turkey. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 33, 1532-1545. 20. Huang, W.Y., Meinschein, W.G., 1979. Sterols as ecological indicators. Geochimica et Cosmochimica Acta 43, 739-745. 21. Czochanska, Z.,Gilbert, T.D., Philp, R.P., Shepard, C.M., Weston, R.J., Wood, T.A., Woolhouse, A.D., 1988. Geochemical application of sterane and triterpane biomarkers to a


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description of oils from the Taranaki Basin in New Zealand. Organic Geochemistry 12, 123135. 22. Hoş-Çebi, F., Korkmaz, S., 2015. Organic geochemistry of Ağaçbaşı Yayla peat deposits, Köprübaşı/Trabzon, NE Turkey. International journal of coal Geology 146, 155-165. 23. Peters, K.E., Moldowan, J.M., 1993. The Biomarker guide: Interpreting molecular fossils in petroleum and ancient sediments. Englewood Cliffs, N.J., Prentice-Hall, New Jersey. 24. Connan, J., Bouroullec, J., Dessort D., Albrecht, P., 1986. The microbial input in carbonateanhydrite facies of a sabkha paleoenvironment from Guatemala: A molecular approach. Organic Geochemistry 10, 29-50. 25. Riva, A., Riolo, J., Mycke, B., Ocampo, R., Callot, H.J., Albrecht, P., Nalı, M.,. 1989. Molecular parameters in Italian carbonate oils: Reconstruction of past depositional environments. Abstract, In: 14th International Meeting on Organic Geochemistry, September 18-22, Paris, 335. 26. Waples, D.W., Machihara, T., 1991. Biomarkers for geologists-a pratical guide to the application of steranes and triterpanes in petroleum geology. AAPG Methods in Exploration Series, No: 9, 85. 27. Peters, K.E., Walters, C.C., Moldowan, J.M., 2005. The Biomarker Guide. In: Biomarkers and Isotopes in Petroleum Exploration and Earth History, second ed., vol. 2. Cambridge University Press, Cambridge, pp. 475-1155. 28. McKirdy, D.M., Aldridge, A.K., Ypma, P.J.M., 1983. A geological comparison of some crude oils from Pre-Ordovician carbonate rocks. In: Bjoroy, M., Albrecht, C., Cornford, C., et al. (Eds.), Advances in Organic Geochemistry 1981. John Wiley & Sons, New York. 29. Rullkötter, J., Spiro, B., Nissenbaum, A., 1985. Biological marker characteristics of oil and asphalts from carbonate source rocks in a rapidly subsiding graben, Dead Sea, Israel. Geochimica et Cosmochimica Acta 49, 1357-1370. 30. Moldowan, J.M., Sundararaman, P., Schoell, M., 1986. Sensitivity of biomarker properties to depositional environment and/or source input in the Lower Toarcian of S.W. Germany. Organic Geochemistry 10, 915-926. 16 ACS Paragon Plus Environment

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31. Hunt, J.M., 1995. Petroleum Geochemistry and Geology. W.H. Freeman and Company, New York. 32. Moldowan, J. M., Seifert, W.K., Gallegos, E.J., 1985. Relationship between petroleum composition and depositional environment of petroleum source rocks. AAPG Bulletin 69, 1255–1268. 33. Volkman, J.K., 1986. A review of sterol markers for marine and terrigenous organic matter. Organic Geochemistry 9, 83-99. 34. Requejo, A. G., 1994. Maturation of petroleum source rocks-II Quantitative changes in extractable hydrocarbon content and composition associated with hydrocarbon generation. Organic Geochemistry 21, 91-105. 35. Hughes, W. B, Holba, A. G.. Dzou, L. I. P., 1995. The ratio of dibenzothiophene to phenanthrene and pristane to phytane as indicators of depositional environment and litology of petroleum in source rocks. Geochimica et Cosmochimica Acta 59, 3581-3598. 36. Waples, D.W., 1985. Geochemistry in Petroleum Exploration. Springer Verlag, Boston 223 pp. 37. Bennett, B., Abbott, G.D., 1999. A natural pyrolysis experiment - hopanes from hopanoic acids? Organic Geochemistry 30, 1509-1516. 38. Seifert, W.K., Moldowan, J.M., 1986. Use of biological markers in petroleum exploration. In: Johns, R.B. (Ed.), Methods in Geochemistry and Geophysics 24, pp. 261-290. 39. Grantham, P.J., 1986. Sterane isomerisation and moretane/hopane ratios in crude oils derived from Tertiary source rocks. Organic Geochemistry 9, 293–304. 40. Kvenvolden, K.A., Simoneit, B.R.T., 1990. Hydrothermally derived petroleum examples from Guaymas Basin, Gulf of California, and Escanaba Trough, northeast Pacific Ocean. AAPG Bulletin 74, 223–237. 41. Kara Gülbay, R., Korkmaz, S., 2012. Occurrences and origin of oils and asphaltites from South East Anatolia (Turkey): Implications from Organic geochemistry. Journal of Petroleum Science and Engineering 90-91, 145-158.


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42. Hussler, G., Chappe, B., Wehrung, P., Albrecht, P., 1981. C27-C29 ring A monoaromatic steroids in Cretaceous black shale. Nature 294, 556-558. 43. El-Gayar. M.Sh., 2005, Aromatic steroids in Mideastern crude oils: Identification and geochemical Application. Petroleum Science and Technology 23, 971-990. 44. Seifert. W. K..Moldowan. J. M.. 1978. Applications of steranes, terpanes and mono-aromatics to the maturation, migration and source of crude oils. Geochimica et Cosmochimica Acta 42, 77-95. 45. Mackenzie, A.S., Hoffmann, C.F., Maxwell, J.R., 1981. Molecular parameters of maturation in the Toarcian shales, Paris Basin, France-III. Changes in aromatic steroid hydrocarbons. Geochimica et Cosmochimica Acta 45, 1345-1355. 46. Abbott, G.D., Levis, C.A., Maxwell, J.R., 1985. Laboratory models for aromatization and isomerization of hydrocarbons in sedimentary basin. Nature 318, 651-653. 47. Beach, F., Peakman, T.M., Abbott, G.D., Sleeman, R., Maxwell, J. R., 1989. Laboratory thermal alteration of triaromatic steroid hydrocarbons. Organic Geochemistry 14, 109-11 48. Radke, M., Willsch, H., Leythaeuser, D., Teichmüller, M., 1982. Aromatic components of coal: Relation of distribution pattern to rank. Geochimica et Cosmochimica Acta 46, 18311848. 49. Radke, M., 1987. Organic geochemistry of aromatic hydrocarbons. In: Brooks. J., Welte, D. (Eds.), Advances in Petroleum Geochemistry, vol. 2. Academic Press. London, pp. 141-205. 50. Stojanovic, K., Jovanciecevic, B., Pevneva, G.S., Golovko, J.A., Golovko, A.K., Pfendt, P., 2001. Maturity assesment of oils from the Sakhalin oil fields in Russia: phenanthrene content as a tool. Organic Geochemistry 32, 721-731. 51. Radke, M., Welte, D.H., Willsch, H., 1986. Maturity parameters based on aromatic hydrocarbons: Influnce of the organic matter type. Organic Geochemistry 10, 51-63. 52. Radke, M., Willsch, H., 1994. Exractable alklydibenzothiophenes in Posidonia Shale (Toarcian) source rocks: Relationship of yields to petroleum formation and expulsion. Geochimica et Cosmochimica Acta 23, 5223-5244.


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FIGURES Figure 1. Geological map of the Oltu-Narman Tertiary Basin (after ref 11). (1) Pre-Jurassic metamorphics and intrusive rocks; (2) Sedimantary sequence of Jurassic to Cretaceous age; (3) Upper Cretaceous flysch; (4) Volcano-sedimentary sequence of Upper Cretaceous age; (5) Ophiolitic melange; (6) Oltu-Narman Tertiary basin and its deposits; (7) Upper Miocene-Pliocene pyroclastic rocks; (8) Plio-Quaternary volcanics; (9) Alluvium Figure 2. (a) Rings made of Oltu Gemstone, (b) bead, rings, earring and wristbands made of Oltu Gemstone. Figure 3. The generalized columnar section of the study area (after ref 12). Figure 4. Field photographs of Oltu Gemstone outcrops. An underground mining site where Oltu Gemstone is exploited (a), field images of Oltu Gemstone in sandstone (b), siltstone (c) and claystone (d), the view of lenticular coals within silty claystone in the underground mining site (e), the images of fossil tree in the Olurdere Formation and Oltu Gemstone forming around it (f). Figure 5. Gas chromatograms of whole extracts from Oltu Gemstone samples. a) OE-1, b) OE-2, c) OE-4, d) OE-5 Figure 6. (a), (b), (c), (d) m/z 217 mass chromatograms showing the distribution of aliphatic steroid of Oltu Gemstone samples; (e), (f), (g), (h) m/z 191 mass chromatograms showing the distribution of the aliphatic hopanoid of Oltu Gemstone samples (OE-1, OE-2, OE-4, OE-5, respectively). Figure 7. Mass chromatograms of m/z 253 showing the distribution of the monoaromatic steroid hydrocarbons (a, b, c, d) an mass chromatograms of m/z 231 showing the distribution of the triaromatic steroid hydrocarbons (e, f, g, h) in the Oltu Gemstone samples (OE-1, OE-2, OE-4, OE-5, respectively). Figure 8. a, b, c, d) mass chromatograms (m/z 178 and 192) showing the disrtibution of phenanthrene and alkylphenanthrenes (P= phenanthrene; MP= methylphenanthrene); e, f, g, h) mass chromatograms (m/z 184, 198) showing the disrtibution of dibenzothiophene and methyldibenzothiophene (DBT = dibenzothiophene, MDBT = methyldibenzothiophene) of Oltu Gemstone samples (OE-1, OE-2, OE-4, OE-5, respectively). Figure 9. The distribution of the Oltu Gemstone samples on (a) HI-Tmax and (b) TOC-S2 kerogen type diagram. Figure 10. Bivariate diagrams of C35S/C34S homohopane-C29/C30 hopane (a), Ts/(Ts+Tm)diasterane/sterane (b), DBT-Pr/Ph (c), 20S/(20S+20R) sterane-ββ/(αα+ββ) sterane (d), 22S/(22S+22R) homohopane-20S/(20S+20R) sterane (e) and ternary diagrams of normal-, iso-, diasterane (N-S, I-S and D-S, respectively) and C27, C28, C29 sterane. 19 ACS Paragon Plus Environment

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TABLES Table 1. Results of TOC and Rock–Eval analysis and calculated parameters for samples from study area. Table 2. The parameters calculated from gas chromatograms for Oltu Gemstone samples Table 3. Biomarker compositions based on m/z 191, 217, 231, 253, 178, 192, 187, 198 mass chromatograms and calculated parameters for Oltu Gemstone samples.


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Table 1 Sample No OE-1 OE-2 OE-3 OE-4 OE-5

Lithological description

TOC (%)

S1 (mgHC/g rock) 13.07 15.72 9.66 15.62 9.11

S2 (mgHC/g rock) 295.98 254.37 265.05 250.30 211.94

S3 (mgCO2/g rock) 0.52 0.72 0.47 1.66 1.71

Oltu Gemstone 78.56 Oltu Gemstone 71.28 Oltu Gemstone 70.01 Oltu Gemstone 74.08 Oltu Gemstone 67.39 *Oltu OE-6 30.25 2.75 127.67 1.50 Gemstone OE-7 Coal 48.81 6.51 97.33 3.83 OE-8 Silty claystone 5.32 0.26 15.48 0.22 * The sample from Oltu Gemstone forming around fossil tree.

436 417 424 416 417

HI (mgH/g TOC) 377 357 379 338 314

OI (mgCO2/g TOC) 1 1 1 2 3

309.05 270.09 274.71 265.92 221.05

PI S1 / (S1+S2) 0.04 0.06 0.04 0.06 0.04

417

422

5

130.42

0.02

19.22

11.03

5.13

425 422

199 291

8 4

103.84 15.74

0.06 0. 02

39.74 3.97

9.07 1.35

4.15 0.23

Tmax (oC)


PY (S1+S2)

RC (%)

PC (%)

MINC (%)

52.65 48.57 46.99 51.65 48.68

25.91 22.71 23.02 22.43 18.71

0.97 2.27 1.48 2.54 1.39

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Table 2 Sample No OE-1 OE-2 OE-4 OE-5

Pr/Ph 0.33 0.63 1.29 1.33

Pr/n-C17 0.20 0.93 4.50 1.05

Ph/n-C18 0.49 0.89 0.93 1.88


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Table 3

C22/C21 Tricyclic Terpane C24/C23 Tricyclic Terpane (C19+C20)/C23 tt.

Sample No OE-1 1.02 0.47 1.20

OE-2 0.37 0.6 3.3

OE-4 0.42 0.58 8.41

OE-5 0.20 0.33 11.02

Ts/(Ts+Tm)

0.37

0.13

0.20

0.12

Moretane/hopane C31 R homohopane/C30 hopane C23 tt/(C23tt+C30 hopane) C25/C26 Tricyclic Terpane C29/C30 hopane C29Ts/(C29H+C29Ts) C30*/C29Ts C30*/(C30H+C30*) 22S/(22S+22R) (for C32) homohopane Sterane/hopane C35S/C34S

0.06 0.06 0.13 2.29 0.42 0.42 1.15 0.26 0.62 5.97 0.83

0.18 0.07 0.07 0.44 0.49 0.03 0.56 1.00 1.03

0.23 0.22 0.28 1.30 0.07 1.39 0.12 0.58 1.32 0.83

0.12 0.19 0.21 1.34 0.04 3.87 0.19 0.58 0.79 0.56

30, 28, 42 26, 40, 34 1.37 0.37 0.24 0.68

29, 31, 40 43, 35, 22 0.05 0.24 0.16 0.78

30, 25, 45 42, 26, 32 0.71 0.33 0.39 0.55

29, 23, 48 42, 31, 27 0.61 0.31 0.36 0.47

Terpanes

Steroids C27, C28, C29 MA steroids (%) MA(I)/MA(I+II) TA(I)/TA(I+II) TA[C20/(C20+C28, 20R)] C28-TA/(C29-MA+C28-TA) C29/(C28+C29) MA

OE-4 4, 40, 56 0.13 0.65

OE-5 5, 26, 69 0.21 0.59

0.17

0.31

0.94

0.90

0.06 0.24

0.40 0.90

0.19 0.58

0.01 0.73

0.31 0.41 0.59 1.01 0.21 0.21 0.11 0.34 0.61

0.34 0.42 0.70 1.30 0.16 0.21 0.12 0.31 0.51

0.38 0.51 0.92 1.37 0.17 0.24 0.12 0.21 0.81

0.41 0.51 0.95 1.32 0.18 0.24 0.14 0.22 0.83

4.00 0.82 0.33

2.80 0.74 0.17

4.00 0.82 0.15

2.80 0.74 0.12

Phenanthrenes MPI-1 MPI-2 MPI-3 (β/α MP) MPR MPR1 MPR2 MPR3 MPR9 1-MP/9-MP

Steranes C27, C28, C29 steranes (%) n-, iso-, diasteranes (%) diasterane/sterane 20S/(20S+20R) for C29 ββ/(ββ+αα) C28/C29

Sample No OE-1 OE-2 0, 76, 24 0, 10, 90 0.03 0.03 0.04 0.27

Dibenzotiophenes MDR MDR' DBT/P

sterane/hopane= C27, C28, C29 αα/ββ (20S+20R)/C29-C33 hopane; MPI-1=1.5(2MP+3MP)/(P+1MP+9MP); MPI-2=3(2MP)/(P+1MP+9MP); MPI-3= (2MP+3-MP)/(1MP+9MP); MPR=2MP/1MP; MPR1=1MP/P; MPR2=2MP/P; MPR3=3MP/P; MPR9=9MP/P; MDR=4MDBT/1MDBT; MDR'=4MDBT/(1MDBT+4MDBT); MA(I)/MA(I+II)= (C21+C22)/(C21+C22+C27+C28+C29); TA(I)/TA(I+II)= (C20+C21)/(C20+C21+C26+C27+C28)


F gure 1.

Page 25 of 34 1 2 3 Q 4 5 6 Oltu Gemstone outcrops 7 8 9 10 11 12 13 14 15 Q 16 17 18 19 20 21 22 23 24 25 26 27 28

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6 7 8 9

N

Alıcık Q

Akşar

Q

Şenkaya OLTU

5

0 Bulgar a Gre.

10 km

Black Sea

Georg a

İstanbul Trabzon Oltu Ankara

Aegean

1 2 3 4 5

Armen a

Erzurum Iran

Iraq

Q

Syr a

Med terranean Sea Trabzon

R ze

Ardahan

Narman Sürmene

0 120 km

Olur

İk zdere

Maçka

Kars

Uzungöl Uzundere

OLTU

İsp r

Bayburt


Aşkale

Tortum

Erzurum

Narman

Sarıkamış

Pas nler Köprüköy

Ağrı Tekman

0

25

50 km

F gure 2.

Energy & Fuels

(a) 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

(b)


Page 26 of 34

(m)

80 Th ckness

650 234

Marl and claystone nterbedded w th gypsum

250

Basalt (dark green coloured columnar jo nt ng)

511

Alternat on of conglomerate, sandstone and s ltstone

Dağd b Karataş 395

Alluv um Terrace

Ol gocene

Upper Pl ocene Pl o-Quaternary Ol gocene TavşanErdavut Del ktaş tepe İğdel

Explanat on

Basalt (dark grey - dark grey green coloured, current bedded conta n ng)

v

v

v

v

v

v

v

v

v

v

v

v

v

v

v

v

v

v

v

v

v

Alternat on of sandstone and tuffite

15

Claystone Conglomerate

384

L mestone, clayey l mestone, marl and claystone

93

Alternat on of sandstone and tuffite

651

Alternat on of sandstone, s ltstone, claystone, marl and l mestone

858

L mestone and sandycherty l mestone

588

Akbayır Karmasor Boğazgören Yeş lbağlar Olurdere

v

Alternat on of sandstone, s ltstone, claystone, marl nterbedded conglomerate, clayey l mestone, tuff and Oltu Gemtone and coal

ACS Paragon Plus Environment Coşkunlar

Upper Cretaceous Lower - Upper Cretaceous Upper Malm Lower Cretaceous L as - Lower Malm

C r e t a c e o u s Jurass c PermoCarbo ferous

L thology

Eocene

T e r t

a r y

I Z O O E N C C I Z O E S

O

Ple s.

Energy & Fuels

30

68

M

PALEOZOIC

Ser es

System

Holoc.

C

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 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53

Quaternary

Upper System

Page 27 of 34

Format on

F gure 3.

Porphyr te gran te, dac te, ryhodac te, ryhol te, andes te, tuff, aglomerate

F gure 4.

Energy & Fuels

(a) 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 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

Page 28 of 34

(b)

(c)

(d)

(e)

(f)


Page 29 of 34

)tJXUH S$

S$

D

F

Q&

Q&

Q&

Q&3U Q&3K Q& Q& Q& Q& Q&

Q&

Q&

Q&

&6

Q&3K Q& 3K Q& Q& Q& Q& Q& Q&

Q& Q&

Q&

&6

Q&

%LRPDUNHUUHJLRQ

E

G

PLQ


Q&

Q&

Q&3U 3K Q& Q& Q&

Q&

Q&

Q&

Q&

Q&

Q&

Q& Q&

Q& Q& 3KQ& Q&

Q& Q&

&6

&6

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 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

PLQ

F gure 6.

Energy Abundance & Fuels C30 hopane

C29 hopane

C29Ts

C30*

Homomoretane

Normoretane

TT29 TT28

TT20

C35

C30 hopane

C34

(f)

C29aaa20R C29 D asteranes

Pregnanes

Homomoretane

Normoretane

Moretane

C29 hopane

C29Ts

TT30

TT29

TT20

C29 hopane Normoretane C30 hopane Moretane

C29Ts

C30*

Tm Ts

Secohopane

TT19

C32

C33

C34

C35

(g)

TT21 TT22 TT23 TT24

C30 Str.

Homohopanes

TT19

(c)

80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0

C31 G

TT20

C29aaa20R

5

TT21 TT22 TT23 TT24

15

Ts

Tm

20

C29aaa20S C29abb20S/20R

Homohopanes

C31

C32

C33

C34

C35

50

(d)

(h)

45

35 C29 hopane

45.00 50.00 55.00 60.00 65.00 70.00 75.00 80.00 85.00 90.00 95.00

T me

45.00 5.00

C30*

C29Ts

TT30R

Ts

Secohopane

5

TT21 TT22 TT23 TT24

30

Tm

15

ACS Paragon Plus 10 Environment C Str.

Normoretane

20

D asteranes

Homohopanes Homomoretane

25

Moretane

30

C30 hopane

C28 Str.

C29aaa20S C29abb20S/20R

40

TT19

C29 D asteranes

C28 Str.

D asteranes

C27 Str.

TT21 TT22

45

25

C30 Str.

C27 Str.

C33

40

10

Pregnanes

C32

G

TT20

D asteranes

Homohopanes C31

30

C28 Str. C29aaa20S C29abb20R/20S

Pregnanes

(e)

35

C29 Str. C29 D asteranes

C27 Str.

TT30S

Tm Ts

C29aaa20R

(b)

TT19

10

TT23

15 C30 Str.

5

TT30R

25 20

TT24

D asteranes

35 30

TT25 Secohopane TT26

Pregnanes

45 40

C29 Str.

C29aaa20S C29abb20R/20S

C27 Str.

(a) C28 Str.

TT25 Secohopane TT26

100

C29aaa20R

110

1 290 380 470 560 650 740 30 8 20 910 10 0 11 12 20 13 18 14 16 15 14 16 12 17 10 18 8 19 6 20 4 21 2 22 23 13 24 12 25 11 26 10 27 9 8 28 7 29 6 30 5 31 4 32 3 33 2 34 1 35 36 11 37 10 38 9 39 8 40 7 41 6 42 5 43 4 44 3 45 2 46 1 47 T me 48

Page 30 of 34

(x10 3) C29 D asteranes

(x10 3) 120

Moretane Oleanane

Abundance

C31

C32

C33

C34

C35

G

65.00 75.00 85.00 95.00 105.00 115.00 125.00 135.00 145.00 155.00

(x10 3) 1800 1700 1600 1500 1400 1300 1200 1100 1000 900 800 700 600 500 400 300 200 100 C21 0

21

21

T me 46.00

C22

C23

50.00

54.00

58.00

62.00

66.00

70.00

74.00

5a-C29(20R)

5a-C29 (20S)

78.00 10

30

(d)

82.00

20

25

86.00

0 T me C22

25 C20

20

10 15

5 C21

5

21

55.00 C22

30

15

C20

ACS Paragon Plus Environment C 10

C22

60.00

65.00

70.00

75.00

80.00

85.00

90.00

C29 (20R)

(c) C21

C29 (20R)

20

C28 (20R)

30

C28 (20R)

40

C27(20R) C28(20R)

C28(20S)

50

C26(20R)+C27(20S)

5b-C29 (20R)+d a-C29 (20R)

(b)

5b-C28 (20R)+d a-C28 (20R) 5b-C29 (20S)+d a-C29 (20S)

5a-C29(20R)

5a-C29 (20S) 5b-C29 (20R)+d a-C29 (20R)

5a-C28 (20S)

C28(20R)

C28(20S)

C27(20R

C26(20R)+C27(20S)

1800 1700 1600 1500 1400 1300 1200

C28 (20S) C27 (20R)

5a-C29(20R)

5a-C29 (20S)

5a-C28 (20S) 5b-C28 (20R)+d a-C28 (20R) 5b-C29 (20S)+d a-C29 (20S)

C22

1100 1000 900 800 700 600 500 400 300 200 100 0

C26 (20R)+C27 (20 S)

5b-C29 (20R)+d a-C29 (20R)

5b-C28 (20R)+d a-C28 (20R) 5b-C29 (20S)+d a-C29 (20S)

(a)

C28 (20S) C27 (20R)

5a-C29(20R)

5a-C29 (20S)

5a-C27 (20R) 5a-C28 (20S)

5b-C28 (20S)+d a-C28 (20S)

F gure 7.

Page 31 of 34

C26 (20R)+C27 (20 S)

5b-C29 (20R)+d a-C29 (20R)

5b-C28 (20R)+d a-C28 (20R) 5b-C29 (20S)+d a-C29 (20S)

5b-C27 (20R)+d a-C27 (20R) 5a-C27 (20S) 5b-C28 (20S)+d a-C28 (20S)

21

5a-C27 (20R) 5a-C28 (20S)

C23

5b-C27 (20R)+d a-C27 (20R) 5a-C27 (20S) 5b-C28 (20S)+d a-C28 (20S)

C22

5b-C27 (20S) d a-C27 (20S)

5b-C28 (20S)+d a-C28 (20S)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 400 15 16 350 17 300 18 19 250 20 200 21 22 150 23 10 24 C 25 50 26 0 27 105 28 100 95 29 90 30 85 80 31 75 32 70 65 33 60 55 C 34 50 35 45 40 36 35 37 30 25 38 20 15 39 10 40 5 0 41 42 170 160 43 150 44 140 45 C 130 120 46 110 47 100 48 90 80 49 70 50 60 51 50 40 52 30 53 20 54 10 55 0

5b-C27 (20S) d a-C27 (20S)

Abundance (x10 3)

EnergyAbundance & Fuels

(e)

C20 C21 C 22

100 90

80

(f)

70

60 C20

C22

0

60

50 55

(g)

40 45

35

0

70 75

60 65

(h)

50 55

40

45

35

95.00

100.00

105.00

F gure 8.

EnergyAbundance & Fuels

Abundance

T me

P

4-MDBT 2-MDBT

(f)

DBT

1200

1-MDBT

3-MP

2-MP

1-MP

9-MP

(a)

1100 1000

(b)

(g)

900 2-MDBT

800 600 500 4-MDBT

400 300 200

1-MDBT

1-MP

3-MP 2-MP

9-MP

700

100 0

2-MDBT 4-MDBT

600 P

(g)

1-MDBT

(c)

DBT

P

DBT

900 850 800 750 700 650 600 550 500 450 400 350 300 250 200 150 100 50 0

3-MP 2-MP 9-MP 1-MP

550

(d)

(h)

500 450 400 350 300 4-MDBT 2-MDBT

250 200

ACS Paragon Plus150 Environment 100 50

33.00

36.00

39.00

42.00

45.00

48.00

51.00

54.00

57.00

T me 22.00

25.00

28.00

31.00

34.00

1-MDBT

1 2 3 4 5 6 7 8 9 10 7000 11 6500 6000 12 5500 13 5000 4500 14 4000 15 3500 3000 16 2500 17 2000 18 1500 1000 19 500 20 0 21 6000 22 5500 23 5000 4500 24 4000 25 3500 26 3000 27 2500 28 2000 29 1500 30 1000 31500 32 0 33 5000 34 4500 35 4000 36 3500 37 3000 38 2500 39 2000 40 1500 41 1000 42 500 43

3000 2800 2600 2400 2200 2000 1800 1600 1400 1200 1000 800 600 400 200 0

P

3-MP 2-MP 9-MP 1-MP

8000 7500 7000 6500 6000 5500 5000 4500 4000 3500 3000 2500 2000 1500 1000 500 0

Page 32 of 34

(x10 3)

DBT

(x10 3)

37.00

40.00

43.00

46.00

49.00

F gure 9.

Page 33 of 34

0. 5% R o

Oltu Gemstone Coal S lty claystone

500

(b)

5%

Ro

S2 (mg HC/g rock)

II.Type

1. 3

Hydrogen Index (HI) (mg HC/gTOC)

(a)

I.Type

1000

1 2 3 800 4 5 600 6 7 8 400 9 10 11200 12 13 14 0 15 16

Energy & Fuels

III.Type

400 Type I

OC gT

300

/ HC

0

0 =7

200

mg

Type III

ACS Paragon0Plus Environment 400

465

500

Tmax (oC)

mmature mature

overmature

gTOC

gHC/

00 m

HI=2

100

430

Type II

HI

0

20

40 60 TOC % wt.

80

100

F gure 10.

Energy & Fuels 0.7 20S/(20S+20R) (C29 )

Endpo nt

0.5

Mature

0.4

Low mature

0.3 0.2

Immature

0.1 0 0.4

0.6

0.8

1.0

1.2

1.4

1.6

0.1

0

0.2

C29/C30 hopane

0.3

0.4

0.5

0.7

0.6

bb/(aa+bb) (C29) 0.7

(e)

0.6

Endpo nt

0.5

Endpo nt

Ts/(Ts+Tm)

1 20.8 3 40.6 5 0.4 6 7 0.2 8 90 10 0 0.2 11 12 0.4 13 (b) 14 15 16 0.3 17 18 19 0.2 20 21 22 23 0.1 24 0.2 0 25 26 6 27 (c) 28 5 29 1A 30 4 31 32 3 33 34 2 1B 35 361 2 37 380 0 1 39

Page 34 of 34

(d)

0.6

1.0

22S/(22S+22R) (C32)

C35S/C34S Homohopane

(a)

Endpo nt

1.2

0.4 0.3 0.2 0.1 0

0.6 0.8 1.0 Diasterane/sterane

1.2

1.4

1.6

0.1

0

0.2

0.3

0.4

0.5

20S/(20S+20R) (C29 ) C28

0 100

(f)

1A Mar ne carbonate 1B Mar ne carbonate Mar ne marl Lacustr ne sulphate-r ch 2 Lacustr ne sulphate-poor 3 Mar ne shale and other lacustr ne 4 Fluv al/Delta c

I-S.

0 100 20 20

80

80 40

DBT/P

0.4

40

60 60

60

40

60

40 80

20

80

20

100 ACS 4 Paragon Plus Environment C

3

27 0

100

2

3 Pr/Ph

4

5

6

N-S. 0

20

20 40

40 60

60 80

0 100 D-S.

80

0 C 100 29

Organic Geochemistry and Depositional Environment of the Oltu

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