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Roger E Summons - One of the best experts on this subject based on the ideXlab platform.

  • Organic Geochemistry of the early toarcian oceanic anoxic event in hawsker bottoms yorkshire england
    Earth and Planetary Science Letters, 2014
    Co-Authors: Katherine L French, Julio Sepulveda, Joao Trabuchoalexandre, Darren R Grocke, Roger E Summons
    Abstract:

    A comprehensive Organic geochemical investigation of the Hawsker Bottoms outcrop section in Yorkshire, England has provided new insights about environmental conditions leading into and during the Toarcian oceanic anoxic event (T-OAE; ∼183 Ma). Rock-Eval and molecular analyses demonstrate that the section is uniformly within the early oil window. Hydrogen index (HI), Organic petrography, polycyclic aromatic hydrocarbon (PAH) distributions, and tricyclic terpane ratios mark a shift to a lower relative abundance of terrigenous Organic matter supplied to the sampling locality during the onset of the T-OAE and across a lithological transition. Unlike other ancient intervals of anoxia and extinction, biomarker indices of planktonic community structure do not display major changes or anomalous values. Depositional environment and redox indicators support a shift towards more reducing conditions in the sediment porewaters and the development of a seasonally stratified water column during the T-OAE. In addition to carotenoid biomarkers for green sulfur bacteria (GSB), we report the first occurrence of okenane, a marker of purple sulfur bacteria (PSB), in marine samples younger than ∼1.64 Ga. Based on modern observations, a planktonic source of okenane's precursor, okenone, would require extremely shallow photic zone euxinia (PZE) and a highly restricted depositional environment. However, due to coastal vertical mixing, the lack of planktonic okenone production in modern marine sulfidic environments, and building evidence of okenone production in mat-dwelling Chromatiaceae, we propose a sedimentary source of okenone as an alternative. Lastly, we report the first parallel compound-specific View the MathML source record in marine- and terrestrial-derived biomarkers across the T-OAE. The View the MathML source records of short-chain n-alkanes, acyclic isoprenoids, and long-chain n -alkanes all encode negative carbon isotope excursions (CIEs), and together, they support an injection of isotopically light carbon that impacted both the atmospheric and marine carbon reservoirs. To date, molecular View the MathML source records of the T-OAE display a negative CIE that is smaller in magnitude compared to the bulk Organic View the MathML source excursion. Although multiple mechanisms could explain this observation, our molecular, petrographic, and Rock-Eval data suggest that variable mixing of terrigenous and marine Organic matter is an important factor affecting the bulk Organic View the MathML source records of the T-OAE.

  • Organic Geochemistry of the early toarcian oceanic anoxic event in hawsker bottoms yorkshire england
    Earth and Planetary Science Letters, 2014
    Co-Authors: Katherine L French, Julio Sepulveda, Joao Trabuchoalexandre, Darren R Grocke, Roger E Summons
    Abstract:

    A comprehensive Organic geochemical investigation of the Hawsker Bottoms outcrop section in Yorkshire, England has provided new insights about environmental conditions leading into and during the Toarcian oceanic anoxic event (T-OAE; ∼183 Ma). Rock-Eval and molecular analyses demonstrate that the section is uniformly within the early oil window. Hydrogen index (HI), Organic petrography, polycyclic aromatic hydrocarbon (PAH) distributions, and tricyclic terpane ratios mark a shift to a lower relative abundance of terrigenous Organic matter supplied to the sampling locality during the onset of the T-OAE and across a lithological transition. Unlike other ancient intervals of anoxia and extinction, biomarker indices of planktonic community structure do not display major changes or anomalous values. Depositional environment and redox indicators support a shift towards more reducing conditions in the sediment porewaters and the development of a seasonally stratified water column during the T-OAE. In addition to carotenoid biomarkers for green sulfur bacteria (GSB), we report the first occurrence of okenane, a marker of purple sulfur bacteria (PSB), in marine samples younger than ∼1.64 Ga. Based on modern observations, a planktonic source of okenane's precursor, okenone, would require extremely shallow photic zone euxinia (PZE) and a highly restricted depositional environment. However, due to coastal vertical mixing, the lack of planktonic okenone production in modern marine sulfidic environments, and building evidence of okenone production in mat-dwelling Chromatiaceae, we propose a sedimentary source of okenone as an alternative. Lastly, we report the first parallel compound-specific δC13 record in marine- and terrestrial-derived biomarkers across the T-OAE. The δC13 records of short-chain n-alkanes, acyclic isoprenoids, and long-chain n-alkanes all encode negative carbon isotope excursions (CIEs), and together, they support an injection of isotopically light carbon that impacted both the atmospheric and marine carbon reservoirs. To date, molecular δC13 records of the T-OAE display a negative CIE that is smaller in magnitude compared to the bulk Organic δC13 excursion. Although multiple mechanisms could explain this observation, our molecular, petrographic, and Rock-Eval data suggest that variable mixing of terrigenous and marine Organic matter is an important factor affecting the bulk Organic δC13 records of the T-OAE.

  • Organic Geochemistry of the early toarcian oceanic anoxic event in hawsker bottoms yorkshire england
    Other repository, 2014
    Co-Authors: Katherine L French, Julio Sepulveda, Joao Trabuchoalexandre, Darren R Grocke, Roger E Summons
    Abstract:

    Article history: A comprehensive Organic geochemical investigation of the Hawsker Bottoms outcrop section in Yorkshire, England has provided new insights about environmental conditions leading into and during the Toarcian oceanic anoxic event (T-OAE; ∼183 Ma). Rock-Eval and molecular analyses demonstrate that the section is uniformly within the early oil window. Hydrogen index (HI), Organic petrography, polycyclic aromatic hydrocarbon (PAH) distributions, and tricyclic terpane ratios mark a shift to a lower relative abundance of terrigenous Organic matter supplied to the sampling locality during the onset of the T-OAE and across a lithological transition. Unlike other ancient intervals of anoxia and extinction, biomarker indices of planktonic community structure do not display major changes or anomalous values. Depositional environment and redox indicators support a shift towards more reducing conditions in the sediment porewaters and the development of a seasonally stratified water column during the T-OAE. In addition to carotenoid biomarkers for green sulfur bacteria (GSB), we report the first occurrence of okenane, a marker of purple sulfur bacteria (PSB), in marine samples younger than ∼1.64 Ga. Based on modern observations, a planktonic source of okenane's precursor, okenone, would require extremely shallow photic zone euxinia (PZE) and a highly restricted depositional environment. However, due to coastal vertical mixing, the lack of planktonic okenone production in modern marine sulfidic environments, and building evidence of okenone production in mat-dwelling Chromatiaceae, we propose a sedimentary source of okenone as an alternative. Lastly, we report the first parallel compound-specific δ 13 Cr ecord in

Peirong Wang - One of the best experts on this subject based on the ideXlab platform.

  • Organic Geochemistry of oil and gas in the kuqa depression tarim basin nw china
    Organic Geochemistry, 2003
    Co-Authors: Shuichang Zhang, Digang Liang, Jianping Chen, Feiyu Wang, Peirong Wang
    Abstract:

    Abstract The Kuqa depression in the Tarim Basin, NW China contains significant natural gas and condensate resources, with only small amounts of black oil. This study demonstrates that the primary reason for the accumulation of large natural gas reserves in the Kuqa depression is the high maturity level of the Jurassic coal-bearing sequence that is currently at the peak stage of dry gas generation. From the combined stable carbon isotopes and molecular biomarker data it is possible to identify two separate source rocks for the discovered hydrocarbon fluids: the gases were primarily from the Middle-Lower Jurassic coals and associated clastic rocks, and the oils were from the Upper Triassic lacustrine mudstones. Peak oil generation from the Triassic source rocks occurred during the early Miocene (23–12 Ma b.p.). These oils migrated laterally over relatively long distances (∼20–50 km) reaching the outer periphery of the depression. Peak gas generation took place more recently, perhaps during the past 5 Ma. The gases migrated mainly along faults over relatively short lateral distances, resulting in accumulations adjacent to the over-matured source kitchens. Different timings for the trap formation along the north and south margins and a late injection of gas into early oil accumulations provided favorable conditions for the formation of evaporative condensates and the preservation of gas pools in the more down-dip reservoirs and oil pools in the more up-dip locations.

Katherine L French - One of the best experts on this subject based on the ideXlab platform.

  • Organic Geochemistry of the early toarcian oceanic anoxic event in hawsker bottoms yorkshire england
    Earth and Planetary Science Letters, 2014
    Co-Authors: Katherine L French, Julio Sepulveda, Joao Trabuchoalexandre, Darren R Grocke, Roger E Summons
    Abstract:

    A comprehensive Organic geochemical investigation of the Hawsker Bottoms outcrop section in Yorkshire, England has provided new insights about environmental conditions leading into and during the Toarcian oceanic anoxic event (T-OAE; ∼183 Ma). Rock-Eval and molecular analyses demonstrate that the section is uniformly within the early oil window. Hydrogen index (HI), Organic petrography, polycyclic aromatic hydrocarbon (PAH) distributions, and tricyclic terpane ratios mark a shift to a lower relative abundance of terrigenous Organic matter supplied to the sampling locality during the onset of the T-OAE and across a lithological transition. Unlike other ancient intervals of anoxia and extinction, biomarker indices of planktonic community structure do not display major changes or anomalous values. Depositional environment and redox indicators support a shift towards more reducing conditions in the sediment porewaters and the development of a seasonally stratified water column during the T-OAE. In addition to carotenoid biomarkers for green sulfur bacteria (GSB), we report the first occurrence of okenane, a marker of purple sulfur bacteria (PSB), in marine samples younger than ∼1.64 Ga. Based on modern observations, a planktonic source of okenane's precursor, okenone, would require extremely shallow photic zone euxinia (PZE) and a highly restricted depositional environment. However, due to coastal vertical mixing, the lack of planktonic okenone production in modern marine sulfidic environments, and building evidence of okenone production in mat-dwelling Chromatiaceae, we propose a sedimentary source of okenone as an alternative. Lastly, we report the first parallel compound-specific View the MathML source record in marine- and terrestrial-derived biomarkers across the T-OAE. The View the MathML source records of short-chain n-alkanes, acyclic isoprenoids, and long-chain n -alkanes all encode negative carbon isotope excursions (CIEs), and together, they support an injection of isotopically light carbon that impacted both the atmospheric and marine carbon reservoirs. To date, molecular View the MathML source records of the T-OAE display a negative CIE that is smaller in magnitude compared to the bulk Organic View the MathML source excursion. Although multiple mechanisms could explain this observation, our molecular, petrographic, and Rock-Eval data suggest that variable mixing of terrigenous and marine Organic matter is an important factor affecting the bulk Organic View the MathML source records of the T-OAE.

  • Organic Geochemistry of the early toarcian oceanic anoxic event in hawsker bottoms yorkshire england
    Earth and Planetary Science Letters, 2014
    Co-Authors: Katherine L French, Julio Sepulveda, Joao Trabuchoalexandre, Darren R Grocke, Roger E Summons
    Abstract:

    A comprehensive Organic geochemical investigation of the Hawsker Bottoms outcrop section in Yorkshire, England has provided new insights about environmental conditions leading into and during the Toarcian oceanic anoxic event (T-OAE; ∼183 Ma). Rock-Eval and molecular analyses demonstrate that the section is uniformly within the early oil window. Hydrogen index (HI), Organic petrography, polycyclic aromatic hydrocarbon (PAH) distributions, and tricyclic terpane ratios mark a shift to a lower relative abundance of terrigenous Organic matter supplied to the sampling locality during the onset of the T-OAE and across a lithological transition. Unlike other ancient intervals of anoxia and extinction, biomarker indices of planktonic community structure do not display major changes or anomalous values. Depositional environment and redox indicators support a shift towards more reducing conditions in the sediment porewaters and the development of a seasonally stratified water column during the T-OAE. In addition to carotenoid biomarkers for green sulfur bacteria (GSB), we report the first occurrence of okenane, a marker of purple sulfur bacteria (PSB), in marine samples younger than ∼1.64 Ga. Based on modern observations, a planktonic source of okenane's precursor, okenone, would require extremely shallow photic zone euxinia (PZE) and a highly restricted depositional environment. However, due to coastal vertical mixing, the lack of planktonic okenone production in modern marine sulfidic environments, and building evidence of okenone production in mat-dwelling Chromatiaceae, we propose a sedimentary source of okenone as an alternative. Lastly, we report the first parallel compound-specific δC13 record in marine- and terrestrial-derived biomarkers across the T-OAE. The δC13 records of short-chain n-alkanes, acyclic isoprenoids, and long-chain n-alkanes all encode negative carbon isotope excursions (CIEs), and together, they support an injection of isotopically light carbon that impacted both the atmospheric and marine carbon reservoirs. To date, molecular δC13 records of the T-OAE display a negative CIE that is smaller in magnitude compared to the bulk Organic δC13 excursion. Although multiple mechanisms could explain this observation, our molecular, petrographic, and Rock-Eval data suggest that variable mixing of terrigenous and marine Organic matter is an important factor affecting the bulk Organic δC13 records of the T-OAE.

  • Organic Geochemistry of the early toarcian oceanic anoxic event in hawsker bottoms yorkshire england
    Other repository, 2014
    Co-Authors: Katherine L French, Julio Sepulveda, Joao Trabuchoalexandre, Darren R Grocke, Roger E Summons
    Abstract:

    Article history: A comprehensive Organic geochemical investigation of the Hawsker Bottoms outcrop section in Yorkshire, England has provided new insights about environmental conditions leading into and during the Toarcian oceanic anoxic event (T-OAE; ∼183 Ma). Rock-Eval and molecular analyses demonstrate that the section is uniformly within the early oil window. Hydrogen index (HI), Organic petrography, polycyclic aromatic hydrocarbon (PAH) distributions, and tricyclic terpane ratios mark a shift to a lower relative abundance of terrigenous Organic matter supplied to the sampling locality during the onset of the T-OAE and across a lithological transition. Unlike other ancient intervals of anoxia and extinction, biomarker indices of planktonic community structure do not display major changes or anomalous values. Depositional environment and redox indicators support a shift towards more reducing conditions in the sediment porewaters and the development of a seasonally stratified water column during the T-OAE. In addition to carotenoid biomarkers for green sulfur bacteria (GSB), we report the first occurrence of okenane, a marker of purple sulfur bacteria (PSB), in marine samples younger than ∼1.64 Ga. Based on modern observations, a planktonic source of okenane's precursor, okenone, would require extremely shallow photic zone euxinia (PZE) and a highly restricted depositional environment. However, due to coastal vertical mixing, the lack of planktonic okenone production in modern marine sulfidic environments, and building evidence of okenone production in mat-dwelling Chromatiaceae, we propose a sedimentary source of okenone as an alternative. Lastly, we report the first parallel compound-specific δ 13 Cr ecord in

Shuichang Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Organic Geochemistry of oil and gas in the kuqa depression tarim basin nw china
    Organic Geochemistry, 2003
    Co-Authors: Shuichang Zhang, Digang Liang, Jianping Chen, Feiyu Wang, Peirong Wang
    Abstract:

    Abstract The Kuqa depression in the Tarim Basin, NW China contains significant natural gas and condensate resources, with only small amounts of black oil. This study demonstrates that the primary reason for the accumulation of large natural gas reserves in the Kuqa depression is the high maturity level of the Jurassic coal-bearing sequence that is currently at the peak stage of dry gas generation. From the combined stable carbon isotopes and molecular biomarker data it is possible to identify two separate source rocks for the discovered hydrocarbon fluids: the gases were primarily from the Middle-Lower Jurassic coals and associated clastic rocks, and the oils were from the Upper Triassic lacustrine mudstones. Peak oil generation from the Triassic source rocks occurred during the early Miocene (23–12 Ma b.p.). These oils migrated laterally over relatively long distances (∼20–50 km) reaching the outer periphery of the depression. Peak gas generation took place more recently, perhaps during the past 5 Ma. The gases migrated mainly along faults over relatively short lateral distances, resulting in accumulations adjacent to the over-matured source kitchens. Different timings for the trap formation along the north and south margins and a late injection of gas into early oil accumulations provided favorable conditions for the formation of evaporative condensates and the preservation of gas pools in the more down-dip reservoirs and oil pools in the more up-dip locations.

  • molecular Organic Geochemistry of the tarim basin northwest china
    AAPG Bulletin, 2000
    Co-Authors: Andrew D Hanson, Shuichang Zhang, J M Moldowan, D G Liang, Bin Zhang
    Abstract:

    We conducted Organic geochemical analyses on the largest suite of oils and source-rock extracts from the Tarim basin, northwest China, currently available. Statistical cluster analysis of the entire suite of Tarim oils distinguishes at least seven genetic groups of oils. The largest group of oils was collected from the Tazhong and Tabei uplifts and originated from marine Middle-Upper Ordovician anoxic marls that mark slope facies at the margins of structural uplifts. Two other genetic groups most likely originated from marine Middle-Upper Ordovician source rocks, but of distinct facies, with one an oxic shale-rich source west of the Bachu uplift and the other an anoxic shale source at Tazhong.

Digang Liang - One of the best experts on this subject based on the ideXlab platform.

  • Organic Geochemistry of oil and gas in the kuqa depression tarim basin nw china
    Organic Geochemistry, 2003
    Co-Authors: Shuichang Zhang, Digang Liang, Jianping Chen, Feiyu Wang, Peirong Wang
    Abstract:

    Abstract The Kuqa depression in the Tarim Basin, NW China contains significant natural gas and condensate resources, with only small amounts of black oil. This study demonstrates that the primary reason for the accumulation of large natural gas reserves in the Kuqa depression is the high maturity level of the Jurassic coal-bearing sequence that is currently at the peak stage of dry gas generation. From the combined stable carbon isotopes and molecular biomarker data it is possible to identify two separate source rocks for the discovered hydrocarbon fluids: the gases were primarily from the Middle-Lower Jurassic coals and associated clastic rocks, and the oils were from the Upper Triassic lacustrine mudstones. Peak oil generation from the Triassic source rocks occurred during the early Miocene (23–12 Ma b.p.). These oils migrated laterally over relatively long distances (∼20–50 km) reaching the outer periphery of the depression. Peak gas generation took place more recently, perhaps during the past 5 Ma. The gases migrated mainly along faults over relatively short lateral distances, resulting in accumulations adjacent to the over-matured source kitchens. Different timings for the trap formation along the north and south margins and a late injection of gas into early oil accumulations provided favorable conditions for the formation of evaporative condensates and the preservation of gas pools in the more down-dip reservoirs and oil pools in the more up-dip locations.