@article{2-s2.0-85103393331,

title = {Early Oligocene environment of the Central Paratethys revealed by biomarkers and pyrite framboids from the Tarcău and Vrancea Nappes (Eastern Outer Carpathians, Romania)},

author = { M. Wendorff-Belon and M.J. Rospondek and L. Marynowski},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85103393331&doi=10.1016%2fj.marpetgeo.2021.105037&partnerID=40&md5=63d90dba1238ab4db4592ee530b22b84},

doi = {10.1016/j.marpetgeo.2021.105037},

issn = {02648172},

year  = {2021},

date = {2021-01-01},

journal = {Marine and Petroleum Geology},

volume = {128},

publisher = {Elsevier Ltd},

abstract = {The Menilite facies, representing the most prolific hydrocarbon source rocks in the Carpathian fold and thrust belt, has been studied in two outcrop sections of the Vrancea and Tarcău Nappes (Eastern Romania) with the aim of determining the depositional environment during the Early Oligocene in the Vrancea and Tarcău sub-basins of the Central Paratethys. The biomarker composition indicates spatial variability in organic matter sources with mainly algal (particularly diatoms and dinoflagellates) and bacterial contributions in both sub-basins. This is reflected by the occurrence of such biomarkers as triaromatic dinosteroids, C25 highly branched isoprenoid thiophenes, marine n-alkanes, hopanoids and monomethyl alkanes. Solely in the Vrancea domain, the input of terrigenous organic matter of higher plant origin can be anticipated from the presence of abietane-class biomarkers (conifer-derived) and oleanane (angiosperm-derived). Distinct nutrient availability related to different positions of individual sub-basins (i.e. shallower; temporarily eutrophic Vrancea sub-basin vs. open-marine mesotrophic Tarcău domain) is reflected by different paleoproductivity indicators, such as the total organic carbon content, hydrogen index and 17α-hopanes to steranes ratio. Water column stratification with bottom water anoxia enhanced by bacterial sulfate reduction stretching into the chemocline, at least intermittently, is expressed by a characteristic tiny pyrite framboid distribution and the lack of bioturbation. However, molecular indicators (Pr/Ph ratio; C35 homohopane index) imply fluctuations of redox conditions with the dominance of dysoxic conditions, which may suggest the occasional oxidation of bottom waters linked to local upwelling. Early diagenetic organic matter transformations such as photodegradation taking place in the oxidised upper part of the water column could also have affected the biomarker distributions. The presence of aryl isoprenoids and Me,i-Bu-maleimides indicates periods of euxinic conditions within the photic zone only in the Vrancea sub-basin during the deposition of the Lower Menilite Member. This is probably related to freshwater incursions from the adjacent, at least partly emerged forebulge, as suggested by a high MTTC ratio and the occurrence of higher plant-derived organic matter. © 2021 Elsevier Ltd},

note = {2},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{2-s2.0-85009919664,

title = {Organic matter maturity and hydrocarbon potential of the Lower Oligocene Menilite facies in the Eastern Flysch Carpathians (Tarcău and Vrancea Nappes), Romania},

author = { M. Wendorff-Belon and M.J. Rospondek and B. Kluska and L. Marynowski},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85009919664&doi=10.1016%2fj.apgeochem.2017.01.009&partnerID=40&md5=f5f1110690722a102e8dff37461f1dc0},

doi = {10.1016/j.apgeochem.2017.01.009},

issn = {08832927},

year  = {2017},

date = {2017-01-01},

journal = {Applied Geochemistry},

volume = {78},

pages = {295-310},

publisher = {Elsevier Ltd},

abstract = {Bulk organic geochemical and molecular composition data have been used to analyse the hydrocarbon potential and organic matter maturity of the Lower Oligocene Menilite facies from two adjacent tectonic units of the Eastern Flysch Carpathians (Tarcău and Vrancea Nappes), Romania due to the importance of these source rocks in hydrocarbon exploration in entire Paratethys realm. The data show strong variability in organic matter quantity and quality. Organic carbon content reaches peak values in the siliceous facies of the Lower Menilite Member (up to 8.6 wt% TOC), which contains type II kerogen. With increasing contribution of flysch sedimentation mixed type II/III kerogen gains importance. The biomarker distribution reveals strong variation in the supplied organic matter common for flysch-influenced sedimentary environments. Terrigenous input is marked by epicuticular wax imprint in n-alkane distribution and occurrence of conifer biomarkers, while marine organic matter origin is expressed by the occurrence of short-chain n-alkanes and hopanes especially in the siliceous facies. Thus, these source rocks can be classified as oil-prone and subordinately mixed oil/gas-prone. The maturity in the outer tectonic unit (Vrancea) is low (Tmax ∼425 °C; Ro ∼0.4%) but increases towards the inner Tarcău Nappe (Tmax ∼430 °C; Ro ∼0.5%) reaching onset of hydrocarbon generation. The studied rocks have good petroleum potential, but hydrocarbons were generated only in more mature Tarcău Nappe, where solid bitumen veins were observed. Bitumen impregnation of numerous vitrinite grains possibly suppressed vitrinite reflectance, thus leading to more accurate maturity assessment based on molecular proxies (biomarker maturity indices). The observed difference in maturity levels between the nappes results from the more inner position of the sampled Tarcău Nappe succession within the orogen relative to the Vrancea unit. This is related to different burial histories, as well as variation in subsequent erosion and exhumation levels. The actual hydrocarbon potential in the studied area varies due to local interplay of these critical factors. © 2017 Elsevier Ltd},

note = {10},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{2-s2.0-84873086158,

title = {The Werra cyclotheme (Upper Permian, Fore-Sudetic Monocline, Poland): Insights into fluctuations of the sedimentary environment from organic geochemical studies},

author = { B. Kluska and M.J. Rospondek and L. Marynowski and P. Schaeffer},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873086158&doi=10.1016%2fj.apgeochem.2012.09.010&partnerID=40&md5=9d4a9834c9d2a7c19b45a201e1253d6c},

doi = {10.1016/j.apgeochem.2012.09.010},

issn = {08832927},

year  = {2013},

date = {2013-01-01},

journal = {Applied Geochemistry},

volume = {29},

pages = {73-91},

abstract = {A study of the extracts of samples recording a transgressive-regressive succession of the Werra cyclothem, Zechstein (Upper Permian), from the southern margin of the European Permian Basin (the Fore-Sudetic Monocline; Poland) provides an insight into major sources of organic matter and diagenetic processes. The studied cross-section comprises all lithologies representative for the European basin, including transgressive sandstones (Weissliegend) and organic-rich shales (Kupferschiefer) followed by carbonates as well as regressive anhydrites with intercalations of rock salt. Due to the variable influence of overlapping diagenetic processes that affected the organic matter, i.e. maturation and late diagenetic oxidation related to base metal mineralisation, a reliable comparison of the biomarker results is only possible for the major upper part of the section (ca. 38. m; including carbonates and evaporites) but not for the oxidised first 2-3. m from the base of the Kupferschiefer.The transition from carbonate to evaporate sedimentation is associated with a shift to predominant even C-numbered n-alkanes, increased abundance of carotanes and high homohopane index reflecting enhanced reducing conditions. The presence of the C25 regular isoprenoid, squalane, biphytane and the rapid decrease in the pristane/phytane ratio in the evaporites are mainly controlled by the important contribution from both halophilic and methanogenic archaea. The occurrence of gammacerane in the anhydrites suggests development of water column stratification at some stages of the sea regression. This is associated with appearance of specific aryl isoprenoids with a lycopane carbon skeleton most likely related to Botrycoccus braunii race L algae. Lycopane derivative occurrence suggests that such an algal race could have occurred since Permian (currently known Recent-Eocene). The presence of the abundant freshwater/brackish algal biomarkers in evaporititic deposits can be envisaged in the costal part of the Zechstein basin with temporary salt wedge estuary water stratification. The algae bloomed in the top fertile fresh/brackish water layer fed by rivers, and the algal biomass was deposited on the sea floor covered with evaporitic brine. The stratification periodically broke down during precipitation of the rock salt, presumably due to a decrease in riverine water input, as revealed by characteristic disappearance of gammacerane and hopane distributions similar to those observed for the carbonate rocks.The methylphenanthrenes/phenanthrene ratio was used together with methyldibenzothiophenes/ dibenzothiophene ratio to assess maturity. These maturity estimations indicate that the peak of oil window has been reached, which is confirmed by other biomarker maturity parameters based on sterane and hopane distributions. The maturity stage of oil generation and expulsion was further confirmed by the presence of solid bitumen as cements in the sandstone underlying Kupferschiefer and bitumen veins and lenses in the carbonates. © 2012 Elsevier Ltd.},

note = {22},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{2-s2.0-68749092895,

title = {Novel aryl polycyclic aromatic hydrocarbons: Phenylphenanthrene and phenylanthracene identification, occurrence and distribution in sedimentary rocks},

author = { M.J. Rospondek and L. Marynowski and A. Chachaj and M. Góra},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-68749092895&doi=10.1016%2fj.orggeochem.2009.06.001&partnerID=40&md5=988bfcf8b3a3a1fa5b121ba0fce577ba},

doi = {10.1016/j.orggeochem.2009.06.001},

issn = {01466380},

year  = {2009},

date = {2009-01-01},

journal = {Organic Geochemistry},

volume = {40},

number = {9},

pages = {986-1004},

abstract = {Numerous reports have recognised the presence of compounds with molecular weight 254 a.m.u. in aromatic fractions. However, their unequivocal identification has not been achieved due to a lack of reference substances. In geological samples, such m/z 254 compounds could potentially be represented by a number of structural isomers of binaphthyl, phenylphenanthrene, phenylanthracene and indenofluorene with each compound type possessing several positional isomers. In this work, all these m/z 254 compounds, with the exception of the tentatively recognised indenofluorenes, have been unequivocally identified in sedimentary rocks for the first time. Comparison of the mass spectra and the gas chromatography (GC) retention times of synthesised standards with the natural compounds in rocks shows that the major components of aromatic fractions are phenylphenanthrene isomers and, to a lesser extent, binaphthyls and 9-phenylanthracene. The elution sequence expressed as standard retention indices of all these m/z 254 isomers were determined by using high resolution capillary GC with three stationary phases: 5%, 35% and 50% (mole fraction) phenyl substituted methylpolysiloxane on HP-5MS, DB-35MS and DB-17MS columns, respectively. A survey of more than 350 sedimentary rock samples of varying origins and maturity (Rr 0.3-1.4%) reveals that relative abundances of the m/z 254 isomers depend on the maturity of the organic matter. The isomers initially appear at the onset of oil generation (Rr > 0.5%) exclusively in diagenetically/catagenetically oxidised samples containing varying proportions of Types II and III kerogen. Interestingly, all five possible positional phenylphenanthrene isomers (including the most sterically hindered isomer 4-phenylphenanthrene) are present from the beginning of the oil generation window. Such a distribution suggests that low-regioselectivity reactions are likely to be involved in the formation. Interaction, during maturation, of phenyl radicals from primary cracking with aromatic moieties of more resistant terrigenic components of kerogen in an oxidising diagenetic realm is postulated to be responsible for the neoformation of phenylated aromatics in geological samples. Up to the final stages of oil generation, the evolution of the phenyl PAH distributions presumably involve 1,2-phenyl shift reactions and cyclisation, if allowed by the molecular geometry. A near thermodynamically-controlled distribution, with only 3- and 2-phenylphenanthrene and minor 2,2′-binaphthyl remaining, is approached when vitrinite reflectance reaches 1.2% (Rr). The three compounds seem to be persistent beyond the oil window as is suggested by their presence in hydrothermal oil formed at T > 300 °C. © 2009 Elsevier Ltd. All rights reserved.},

note = {36},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{2-s2.0-84962394021,

title = {Comparison of phenyldibenzothiophene distributions predicted from molecular modelling with relevant experimental and geological data},

author = { M.J. Rospondek and M. Szczerba and K. Malek and M. Góra and L. Marynowski},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84962394021&doi=10.1016%2fj.orggeochem.2008.06.012&partnerID=40&md5=4b3d05dfd3a818565ef86524432fa2d6},

doi = {10.1016/j.orggeochem.2008.06.012},

issn = {01466380},

year  = {2008},

date = {2008-01-01},

journal = {Organic Geochemistry},

volume = {39},

number = {12},

pages = {1800-1815},

publisher = {Elsevier Ltd},

abstract = {Evaluation of the relative thermodynamic stabilities of phenyldibenzothiophenes, by means of molecular modelling, has led to the prediction of their equilibrium mixture composition. The calculated equilibrium composition shifts towards that obtained in a laboratory maturation experiment and encountered in mature geological samples (mean vitrinite reflectance Rr ≳ 1.2%). Close inspection of a suite of samples, having in common hydrothermal oxidation of organic matter, but varying in maturity, suggests that phenyldibenzothiophenes can isomerise and also cyclise to triphenyleno[1;12-bcd]thiophene. Both reactions are thermodynamically possible as a result of the relative decrease in enthalpy along the reaction paths and the resulting competition for the precursor 1-phenyldibenzothiophene. Changes in the phenyldibenzothiophene positional isomer distributions from kinetically to thermodynamically controlled mixtures are likely to be achieved with an acid catalysed 1,2-phenyl shift, as suggested from our maturation experiment. To validate this hypothesis, ab initio quantum chemical calculations (DFT) were performed, leading to the localisation of potential transition states as well as the determination of activation energies in gas phase and aqueous solution. The isomerisation barriers are significantly lowered by acid catalysis. They are in the range from ΔE(aq) 20.5 to 28.7 kcal/mol, consistent with the early beginning of the isomerisation observed for our samples. With increasing maturity, 1-PhDBT decays rapidly. At very advanced maturity stages the process is often accompanied by the appearance of triphenyleno[1;12-bcd]thiophene, suggesting its simultaneous formation by cyclisation/oxidation. The oxidation is most likely associated in nature via thermochemical sulfate reduction (TSR). The modelling of such a reaction with thiosulfates yielded an energy barrier ΔE(aq) of ca. 64.7 kcal/mol, only when the initial step involved protonation. This energy seems relevant to very advanced stages of diagenesis/catagenesis. The modelled barrier can be lowered by 2-3 kcal/mol at significantly elevated fluid temperatures as a result of changes in the physical properties of water. © 2008 Elsevier Ltd. All rights reserved.},

note = {19},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{2-s2.0-35148837677,

title = {Novel arylated polyaromatic thiophenes: Phenylnaphtho[b]thiophenes and naphthylbenzo[b]thiophenes as markers of organic matter diagenesis buffered by oxidising solutions},

author = { M.J. Rospondek and L. Marynowski and M. Góra},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-35148837677&doi=10.1016%2fj.orggeochem.2007.05.008&partnerID=40&md5=72b0087cd622f31b0f77b2122c89a48f},

doi = {10.1016/j.orggeochem.2007.05.008},

issn = {01466380},

year  = {2007},

date = {2007-01-01},

journal = {Organic Geochemistry},

volume = {38},

number = {10},

pages = {1729-1756},

abstract = {Three naphtho[b]thiophenes (asymmetric dibenzothiophene isomers) are minor components relative to the prevailing dibenzothiophene constituents of aromatic fractions of diagenetically oxidised marine sedimentary rocks. Interestingly, the rocks containing naphtho[b]thiophenes often also contain their arylated derivatives, phenylnaphtho[b]thiophenes, as major components relative to phenyldibenzothiophenes. Both these series are accompanied by other structural isomers, i.e., naphthylbenzo[b]thiophenes. To our knowledge, phenylnaphtho[b]thiophenes and their naphthylbenzo[b]thiophene isomers have not been reported in geological samples and are unambiguously identified here using synthetic standards. The distribution of arylated thiophenic polycyclic aromatic compounds strongly depends on maturity. At low maturity, where kinetically controlled distribution of the arylated thiophenes is expected, the greatest number of isomers is observed, suggesting that low regioselectivity reactions are involved in their formation. At the beginning of the oil window, small amounts of unstable 3-phenylnaphtho[b]thiophenes, together with three 2-phenylnaphtho[b]thiophenes, naphthylbenzo[b]thiophenes, with major 2-(2-naphthyl)benzo[b]thiophene, and all four possible phenyldibenzothiophenes, with abundant kinetically favoured 1- and 4-substituted isomers, are present. Experimental free radical phenylation of dibenzothiophene yielded a phenyldibenzothiophene isomeric distribution very similar to that observed in natural samples, but different from that resulting from ionic phenylation. Since these arylated polycyclic aromatic thiophenes occur exclusively in samples in which sedimentary pyrite was hydrothermally transformed to hematite/goethite as a result of rock interaction with oxidising brines, such solutions, usually rich in benzene, can be considered as a potential source of phenyl species. At more advanced stages of maturity, 3-phenylnaphtho[2;1-b]thiophenes are transformed to 2-phenylnaphtho[2;1-b]thiophenes, as revealed by artificial maturation experiments. In turn, severe heating of 2-phenylnaphtho[2;1-b]thiophene leads to its complete disappearance and the formation of dibenzothiophene and phenyldibenzothiophenes. Under the same conditions, only phenyldibenzothiophenes isomerise, presumably by a 1,2-phenyl shift, and 1-phenyldibenzothiophene also cyclises to triphenyleno[1;12-bcd]thiophene. The thermodynamically controlled distribution of phenyldibenzothiophenes, dominated by 3- and 2-substituted isomers, is reached at about 1.2% Rr (vitrinite reflectance). The distribution is similar to that encountered in hydrothermal petroleum generated above 300 °C in the rift system of the Guayamas Basin. Such a distribution can be experimentally obtained via prolonged heating a mixture of all possible phenyldibenzothiophene isomers at 330 °C in the presence of an acidic clay catalyst. The ratio between the sum of all phenyldibenzothiophenes and 2-phenylnaphtho[b]thiophene plus 2-(2-naphthyl)benzo[b]thiophene changes regularly with advancing maturity, suggesting a potential application of these newly identified compounds for maturity assessment. © 2007 Elsevier Ltd. All rights reserved.},

note = {36},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{2-s2.0-0036070069,

title = {Phenyldibenzofurans and phenyldibenzothiophenes in marine sedimentary rocks and hydrothermal petroleum},

author = { L. Marynowski and M.J. Rospondek and R. Meyer Zu Reckendorf and B.R.T. Simoneit},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036070069&doi=10.1016%2fS0146-6380%2802%2900040-2&partnerID=40&md5=d959cb34404b47d58fd087e4eade8274},

doi = {10.1016/S0146-6380(02)00040-2},

issn = {01466380},

year  = {2002},

date = {2002-01-01},

journal = {Organic Geochemistry},

volume = {33},

number = {7},

pages = {701-714},

abstract = {The phenyl derivatives of dibenzo[b,d]furan and dibenzo[b,d]thiophene, so far not reported in geological samples, have now been identified in some sedimentary rocks, bitumen and hydrothermal petroleum through a comparison of their retention times and mass spectra with those of authentic standards. All four possible positional isomers were detected for each phenyldibenzo[b,d]furan (PhDBF) and phenydibenzo[b,d]thiophene (PhDBT). Their elution sequence is 1-, 4-, 2- and 3-phenyldibenzo[b,d]furan and 1-, 4-, 2- and 3-phenyldibenzo[b,d]thiophene on apolar stationary phases. In contrast to phenyldibenzofurans, the distributions of the thiophene series is controlled mainly by the organic matter maturity. In the most mature samples 4-, 2- and 3-PhDBTs prevail over I-PhDBT, while less mature samples contain mainly 4-PhDBT or 1-PhDBT and 2-, 3-PhDBTs occur at comparable concentrations. However, in samples of low maturity, in addition to the phenyldibenzo[b,d]thiophene C18H12S series, other structural isomers of C18H12S possessing very similar mass spectra were detected. These are likely to be either naphthylbenzo[b]thiophenes and/or phenylnaphtho[b]thiophenes. PhDBFs and PhDBTs are likely to be intermediate products in the formation of more condensed heterocyclic polycyclic aromatic compounds like triphenyleno[1,12-bcd]thiophene and triphenyleno[1,12-bcd]furan, and benzobisbenzofurans and benzobisbenzothiophenes, which are commonly detected in geological samples. © 2002 Elsevier Science Ltd. All rights reserved.},

note = {52},

keywords = {},

pubstate = {published},

tppubtype = {article}

}