Depositional paleoenvironment and source rock characterization across the Toarcian Oceanic Anoxic Event from the eastern Tethys, Tibet, SW China
Depositional paleoenvironment and source rock characterization across the Toarcian Oceanic Anoxic Event from the eastern Tethys, Tibet, SW China
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西藏特提斯东部托阿尔纪大洋缺氧事件沉积古环境及烃源岩特征
DOI：
10.1016/j.coal.2021.103780
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发表时间：
2021-05
影响因子：
5.6
通讯作者：
Yi Haisheng
中科院分区：
文献类型：
--
作者：
Xia Guoqing;Mansour Ahmed;Gentzis Thomas;Li Gaojie;Carvajal-Ortiz Humberto;Ocubalidet Seare;Yi Fan;Yun Chen;Yi Haisheng
该层序沉积于早侏罗世Toarcian Oceanic Anoxic Event （T-OAE）期间，并根据岩相组成进行了生物地层年龄控制研究。目前的方法允许解释局部古环境对T-OAE气候变率的响应，这些响应仍然是基于比隆co演替的孢粉相分析而揭示的。通过可视化孢粉相分析、镜质体反射率（VRo）和总有机碳(TOC)/ rock - eval热解参数，可以对可能的烃源岩特征进行详细的评价。孢粉主要由陆源植物组成，以球形植物花粉粒为主，少量含海相鞭毛藻囊（dinocysts）。标记囊和花粉分类群使得研究的演替被细分为早托瓦纪和晚巴约纪-巴托纪两个不同时代的单位。此外，研究序列的碳同位素剖面显示，下陶拉统油页岩段存在较大的负碳同位素偏移（CIE），这与同期邻近盆地的区域δ13Corg记录相吻合。特提斯东部地区Toarcian下部的区域TOC含量高达21 wt%，而特提斯西部和北部地区的TOC含量较低（约3 wt%）。两个孢粉相组合表明，这些沉积物沉积于远端内浅海-河流三角洲环境，并在一定程度上位于咸淡海边缘环境。地球化学筛选表明，大部分样品以干酪根II型和混合型有机质丰度极好至优异为主，生烃能力极好至优异。由Rock-Eval Tmax计算的VRo-eq值与实测的VRo值吻合较好，表明研究层段有机质处于油窗的早期至中期。
An integrated approach based on organic petrographic and geochemical proxies along with palynological and palynofacies analysis were employed using 24 rock samples representing the upper part of the Quse and Sewa formations in the southern Qiangtang Basin, Tibetan Plateau, SW China. This interval was deposited during the Early Jurassic Toarcian Oceanic Anoxic Event (T-OAE) and is investigated to assess the biostratigraphic age control based on palynomorphs composition. The current approach allows for the interpretation of the local paleoenvironmental response to T-OAE climate variability that still unraveled based on palynofacies analysis of the Bilong co succession. Visual palynofacies analysis, vitrinite reflectance (VRo), and total organic carbon (TOC)/Rock-Eval pyrolysis parameters enables a detailed assessment of probable source rock characterization..The palynomorph content comprises mainly terrestrially-derived land-plants, mostly sphaeromorphs pollen grains, with minor content of marine dinoflagellate cysts (dinocysts). Marker dinocysts and pollen taxa allow the subdivision of the studied succession into two age-distinctive units of early Toarcian and late Bajocian-Bathonian. Additionally, carbon isotope profile of the studied succession observed a large negative carbon isotope excursion (CIE) within the lower Toarcian oil shale interval, which is compatible with regional δ13Corg records from adjacent basins at this time. The regional TOC contents of lower Toarcian reached up to 21 wt% in areas of the eastern Tethys compared to lower values in the western Tethys and Boreal (ca. 3 wt%). Two palynofacies assemblages revealed deposition of these deposits in distal inner neritic to fluvio-deltaic environment and to some extent in brackish marginal marine setting. Geochemical screening indicated that most samples were dominated by very good to excellent organic matter richness of kerogen Type II and mixed Type II/III with very good to excellent hydrocarbon generation. The calculated VRo-eq from Rock-Eval Tmax and measured VRo values are in good agreement and showed that the organic matter of the studied interval is in the early to middle stages of the oil window.
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影响因子：
5.6
作者：
A. Mansour;E. Geršlová;I. Sýkorová;Dominik Vöröš
通讯作者：
A. Mansour;E. Geršlová;I. Sýkorová;Dominik Vöröš
DOI：
10.1144/sp427.15
发表时间：
2016-11
期刊：
Special Publications
影响因子：
--
作者：
J. Schnyder;D. Pons;J. Yans;R. Tramoy;Saya Abdulanova
通讯作者：
J. Schnyder;D. Pons;J. Yans;R. Tramoy;Saya Abdulanova
影响因子：
1.5
作者：
J. Riding;W. Walton;D. Shaw
通讯作者：
J. Riding;W. Walton;D. Shaw
DOI：
10.1016/j.palaeo.2007.11.005
发表时间：
2008-02
期刊：
Palaeogeography, Palaeoclimatology, Palaeoecology
影响因子：
--
作者：
J. J. Gómez-J.;A. Goy;M. L. Canales
通讯作者：
J. J. Gómez-J.;A. Goy;M. L. Canales
DOI：
10.1111/j.1755-6724.2005.tb00904.x
发表时间：
2005-06
期刊：
Acta Geologica Sinica ‐ English Edition
影响因子：
--
作者：
Chen Lan;Yin Haisheng;Hu Rui-zhong;Zhong Hong;Zou Yan-rong
通讯作者：
Chen Lan;Yin Haisheng;Hu Rui-zhong;Zhong Hong;Zou Yan-rong