Organic Matter Enrichment of Black Shale at the Turn of Ordovician-Silurian in the Paleosedimentary Center in Southern Sichuan Basin, Upper Yangtze Area
AbstractHerein, integrated vertical variation characteristic analysis was conducted by measuring total organic carbon (TOC), major and trace elements in Upper Ordovician-Lower Silurian (Wufeng-Longmaxi formations) black shale in Weiyuan, Luzhou, and Changning areas, southern Sichuan...
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| Language: | English |
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GeoScienceWorld
2022-05-01
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| Series: | Lithosphere |
| Online Access: | https://pubs.geoscienceworld.org/lithosphere/article/2022/Special%2012/6809092/613972/Organic-Matter-Enrichment-of-Black-Shale-at-the |
| _version_ | 1811332909035945984 |
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| author | Yue Cui Xizhe Li Lingling Han Wei Guo Wei Lin Rui Chang Weijun Shen Yize Huang Chao Qian |
| author_facet | Yue Cui Xizhe Li Lingling Han Wei Guo Wei Lin Rui Chang Weijun Shen Yize Huang Chao Qian |
| author_sort | Yue Cui |
| collection | DOAJ |
| description |
AbstractHerein, integrated vertical variation characteristic analysis was conducted by measuring total organic carbon (TOC), major and trace elements in Upper Ordovician-Lower Silurian (Wufeng-Longmaxi formations) black shale in Weiyuan, Luzhou, and Changning areas, southern Sichuan Basin to clarify the control of organic matter (OM) enrichment in different sublayers. According to the cycle boundary, it was divided into member 1 (submember 1 and submember 2) and member 2 from early to late Longmaxi formation, while it was divided into 4 sublayers from early to late during submember 1 depositional period. Under the warm and humid paleoclimate, high paleoproductivity, and gradually oxic paleoredox conditions, the TOC content (0.22-3.27 wt% in Luzhou area) in Wufeng formation increased gradually from early to late under the cocontrolling of tectonic framework and stagnant sea. After the glacial period, the warm and humid climate of Wufeng formation continued in Longmaxi formation, and TOC content reached the highest in sublayer 1 (2.02-4.02 wt%, 4.78 wt%, and 6.45 wt% in Weiyuan, Luzhou, and Changning areas, respectively), due to the high paleoproductivity and high sea level caused by melting glaciers, causing the extremely anoxic environment. The OM was preserved best. It remains higher in sublayer 2 (2.39 wt%, 3.69-4.18 wt%, and 3.5-3.86 wt% in three areas, respectively) because of the anoxic environment caused by deep water and the high paleoproductivity, but the temporary hot and dry environment has a certain negative impact on the OM preservation. Under the stable paleoproductivity, sublayer 3 has a character of water decreasing slowly, and the suboxic environment led to the decrease of TOC content (3.82-5.28 wt% and 3.77-4.13 wt% in Luzhou and Changning areas, respectively). Meanwhile, that in the yuan area became deeper and the TOC content became relatively higher (1.92-3.33 wt%). Under the open environment, sublayer 4 was controlled by lower sea level caused by regression, resulting in lower TOC content (1.31-4.57 wt%, 1.64-3.52 wt%, and 3.88-4.49 wt% in three areas, respectively). However, the global regression of the submember 2 period, high terrigenous debris dilution, and oxic environment lead to the no preservation of OM. Generally speaking, the enrichment of OM is not only affected by the changes of global sea level and paleoproductivity to some extent (Longmaxi shale) but also controlled by the tectonic framework in Sichuan Basin (Wufeng shale). The findings of this study can help for a better understanding of the OM enrichment mechanism and provide a theoretical basis for the evaluation of high-quality source rocks. |
| first_indexed | 2024-04-13T16:44:07Z |
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| language | English |
| last_indexed | 2024-04-13T16:44:07Z |
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| series | Lithosphere |
| spelling | doaj.art-ca72995401e84dc78132676b04e270b42022-12-22T02:39:09ZengGeoScienceWorldLithosphere1941-82641947-42532022-05-012022Special 1210.2113/2022/6809092Organic Matter Enrichment of Black Shale at the Turn of Ordovician-Silurian in the Paleosedimentary Center in Southern Sichuan Basin, Upper Yangtze AreaYue Cui0http://orcid.org/0000-0003-3529-4048Xizhe Li1http://orcid.org/0000-0002-1044-1497Lingling Han2http://orcid.org/0000-0001-7683-3998Wei Guo3Wei Lin4http://orcid.org/0000-0002-8643-594XRui Chang5http://orcid.org/0000-0002-6876-095XWeijun Shen6http://orcid.org/0000-0003-3658-8670Yize Huang7http://orcid.org/0000-0001-8225-6787Chao Qian8http://orcid.org/0000-0002-8729-8342University of Chinese Academy of Sciences Beijing 100049 China ucas.ac.cnUniversity of Chinese Academy of Sciences Beijing 100049 China ucas.ac.cnUniversity of Chinese Academy of Sciences Beijing 100049 China ucas.ac.cnResearch Institute of Petroleum Exploration & Development Beijing 100083 China cnpc.com.cnSchool of Geoscience Yangtze University Wuhan 430100 China yangtzeu.edu.cnCNOOC International Ltd. Beijing 100028 ChinaKey Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of Mechanics Chinese Academy of Sciences Beijing 100190 China cas.cnUniversity of Chinese Academy of Sciences Beijing 100049 China ucas.ac.cnResearch Institute of Petroleum Exploration & Development Beijing 100083 China cnpc.com.cn AbstractHerein, integrated vertical variation characteristic analysis was conducted by measuring total organic carbon (TOC), major and trace elements in Upper Ordovician-Lower Silurian (Wufeng-Longmaxi formations) black shale in Weiyuan, Luzhou, and Changning areas, southern Sichuan Basin to clarify the control of organic matter (OM) enrichment in different sublayers. According to the cycle boundary, it was divided into member 1 (submember 1 and submember 2) and member 2 from early to late Longmaxi formation, while it was divided into 4 sublayers from early to late during submember 1 depositional period. Under the warm and humid paleoclimate, high paleoproductivity, and gradually oxic paleoredox conditions, the TOC content (0.22-3.27 wt% in Luzhou area) in Wufeng formation increased gradually from early to late under the cocontrolling of tectonic framework and stagnant sea. After the glacial period, the warm and humid climate of Wufeng formation continued in Longmaxi formation, and TOC content reached the highest in sublayer 1 (2.02-4.02 wt%, 4.78 wt%, and 6.45 wt% in Weiyuan, Luzhou, and Changning areas, respectively), due to the high paleoproductivity and high sea level caused by melting glaciers, causing the extremely anoxic environment. The OM was preserved best. It remains higher in sublayer 2 (2.39 wt%, 3.69-4.18 wt%, and 3.5-3.86 wt% in three areas, respectively) because of the anoxic environment caused by deep water and the high paleoproductivity, but the temporary hot and dry environment has a certain negative impact on the OM preservation. Under the stable paleoproductivity, sublayer 3 has a character of water decreasing slowly, and the suboxic environment led to the decrease of TOC content (3.82-5.28 wt% and 3.77-4.13 wt% in Luzhou and Changning areas, respectively). Meanwhile, that in the yuan area became deeper and the TOC content became relatively higher (1.92-3.33 wt%). Under the open environment, sublayer 4 was controlled by lower sea level caused by regression, resulting in lower TOC content (1.31-4.57 wt%, 1.64-3.52 wt%, and 3.88-4.49 wt% in three areas, respectively). However, the global regression of the submember 2 period, high terrigenous debris dilution, and oxic environment lead to the no preservation of OM. Generally speaking, the enrichment of OM is not only affected by the changes of global sea level and paleoproductivity to some extent (Longmaxi shale) but also controlled by the tectonic framework in Sichuan Basin (Wufeng shale). The findings of this study can help for a better understanding of the OM enrichment mechanism and provide a theoretical basis for the evaluation of high-quality source rocks.https://pubs.geoscienceworld.org/lithosphere/article/2022/Special%2012/6809092/613972/Organic-Matter-Enrichment-of-Black-Shale-at-the |
| spellingShingle | Yue Cui Xizhe Li Lingling Han Wei Guo Wei Lin Rui Chang Weijun Shen Yize Huang Chao Qian Organic Matter Enrichment of Black Shale at the Turn of Ordovician-Silurian in the Paleosedimentary Center in Southern Sichuan Basin, Upper Yangtze Area Lithosphere |
| title | Organic Matter Enrichment of Black Shale at the Turn of Ordovician-Silurian in the Paleosedimentary Center in Southern Sichuan Basin, Upper Yangtze Area |
| title_full | Organic Matter Enrichment of Black Shale at the Turn of Ordovician-Silurian in the Paleosedimentary Center in Southern Sichuan Basin, Upper Yangtze Area |
| title_fullStr | Organic Matter Enrichment of Black Shale at the Turn of Ordovician-Silurian in the Paleosedimentary Center in Southern Sichuan Basin, Upper Yangtze Area |
| title_full_unstemmed | Organic Matter Enrichment of Black Shale at the Turn of Ordovician-Silurian in the Paleosedimentary Center in Southern Sichuan Basin, Upper Yangtze Area |
| title_short | Organic Matter Enrichment of Black Shale at the Turn of Ordovician-Silurian in the Paleosedimentary Center in Southern Sichuan Basin, Upper Yangtze Area |
| title_sort | organic matter enrichment of black shale at the turn of ordovician silurian in the paleosedimentary center in southern sichuan basin upper yangtze area |
| url | https://pubs.geoscienceworld.org/lithosphere/article/2022/Special%2012/6809092/613972/Organic-Matter-Enrichment-of-Black-Shale-at-the |
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