Response of geochemical characteristics of organic-rich shale of Longmaxi formation to the sedimentary environment in the Neijiang-Rongchang area, Sichuan Basin, China
The Lower Paleozoic (Upper Ordovician–Silurian), a globally deposited organic-rich shale, is one of the most prevalent source rocks worldwide. However, the origin of these shales remains uncertain. Here, this study reports geological and geochemical findings that present novel evidence for the origi...
Saved in:
| Main Authors: | , , , , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Frontiers Media S.A.
2025-07-01
|
| Series: | Frontiers in Earth Science |
| Subjects: | |
| Online Access: | https://www.frontiersin.org/articles/10.3389/feart.2025.1553074/full |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1849316947657752576 |
|---|---|
| author | Licheng Yang Yi Hu Xinrui Yang Lianghua Zhang Wen Tang Dongxi Liu Huilin Li Qibing Wen Lin Xie Xingzhi Wang Jiahao Kang Zhidian Xi Ruiyu Guo |
| author_facet | Licheng Yang Yi Hu Xinrui Yang Lianghua Zhang Wen Tang Dongxi Liu Huilin Li Qibing Wen Lin Xie Xingzhi Wang Jiahao Kang Zhidian Xi Ruiyu Guo |
| author_sort | Licheng Yang |
| collection | DOAJ |
| description | The Lower Paleozoic (Upper Ordovician–Silurian), a globally deposited organic-rich shale, is one of the most prevalent source rocks worldwide. However, the origin of these shales remains uncertain. Here, this study reports geological and geochemical findings that present novel evidence for the origin of these shales. The mineral composition of Lower Silurian Longmaxi shale is dominated by quartz (average: 53.76%) and clay minerals (average: 33.37%). It constitutes a small amount of feldspar, calcite, dolomite, and pyrite. The Longmaxi Formation shale has high organic matter content (more than 2% on average). According to the geochemical indices, such as V/(V + Ni), Ni/Co., U/Th and Mo/total organic carbon (TOC), the Longmaxi Formation shale was deposited in the marine basin environment stranded by the sulphidation of anoxic water. Sensitive elements, such as Ba, Mo, P and Ti, indicate that although the primary productivity of the Longmaxi Formation shale remains low, it still has excellent source rock potential because of superior preservation conditions. A comparative study is conducted with the Lower Silurian hot shale in other parts of the world, it is found that the enrichment of organic matter in the Longmaxi Formation is controlled by high primary productivity (nutrients brought by upwelling) and strong preservation conditions (hypoxia caused by stratified water body), which subverts the traditional cognition of single main controlling factor. The organic matter enrichment of the Lower Silurian thermal shale has a ' productivity-preservation condition ' trade-off mechanism: low latitudes (such as North Africa) are dominated by high productivity. The middle and high latitudes (such as South China) are dominated by strong preservation conditions (limited basin sulfidation). It provides theoretical basis and motivation for future research and effectively guides the exploration and development of unconventional shale gas. |
| format | Article |
| id | doaj-art-6264a35d67c44a0088e5c92a4e35b7f7 |
| institution | Kabale University |
| issn | 2296-6463 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Earth Science |
| spelling | doaj-art-6264a35d67c44a0088e5c92a4e35b7f72025-08-20T03:51:25ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632025-07-011310.3389/feart.2025.15530741553074Response of geochemical characteristics of organic-rich shale of Longmaxi formation to the sedimentary environment in the Neijiang-Rongchang area, Sichuan Basin, ChinaLicheng Yang0Yi Hu1Xinrui Yang2Lianghua Zhang3Wen Tang4Dongxi Liu5Huilin Li6Qibing Wen7Lin Xie8Xingzhi Wang9Jiahao Kang10Zhidian Xi11Ruiyu Guo12Chongqing Gas Field, PetroChina Southwest Oil and Gas Field Company, Chongqing, ChinaState Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, ChinaChongqing Gas Field, PetroChina Southwest Oil and Gas Field Company, Chongqing, ChinaChongqing Gas Field, PetroChina Southwest Oil and Gas Field Company, Chongqing, ChinaChongqing Gas Field, PetroChina Southwest Oil and Gas Field Company, Chongqing, ChinaChongqing Gas Field, PetroChina Southwest Oil and Gas Field Company, Chongqing, ChinaChongqing Gas Field, PetroChina Southwest Oil and Gas Field Company, Chongqing, ChinaChongqing Gas Field, PetroChina Southwest Oil and Gas Field Company, Chongqing, ChinaState Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, ChinaState Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, ChinaState Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, ChinaState Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, ChinaState Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, ChinaThe Lower Paleozoic (Upper Ordovician–Silurian), a globally deposited organic-rich shale, is one of the most prevalent source rocks worldwide. However, the origin of these shales remains uncertain. Here, this study reports geological and geochemical findings that present novel evidence for the origin of these shales. The mineral composition of Lower Silurian Longmaxi shale is dominated by quartz (average: 53.76%) and clay minerals (average: 33.37%). It constitutes a small amount of feldspar, calcite, dolomite, and pyrite. The Longmaxi Formation shale has high organic matter content (more than 2% on average). According to the geochemical indices, such as V/(V + Ni), Ni/Co., U/Th and Mo/total organic carbon (TOC), the Longmaxi Formation shale was deposited in the marine basin environment stranded by the sulphidation of anoxic water. Sensitive elements, such as Ba, Mo, P and Ti, indicate that although the primary productivity of the Longmaxi Formation shale remains low, it still has excellent source rock potential because of superior preservation conditions. A comparative study is conducted with the Lower Silurian hot shale in other parts of the world, it is found that the enrichment of organic matter in the Longmaxi Formation is controlled by high primary productivity (nutrients brought by upwelling) and strong preservation conditions (hypoxia caused by stratified water body), which subverts the traditional cognition of single main controlling factor. The organic matter enrichment of the Lower Silurian thermal shale has a ' productivity-preservation condition ' trade-off mechanism: low latitudes (such as North Africa) are dominated by high productivity. The middle and high latitudes (such as South China) are dominated by strong preservation conditions (limited basin sulfidation). It provides theoretical basis and motivation for future research and effectively guides the exploration and development of unconventional shale gas.https://www.frontiersin.org/articles/10.3389/feart.2025.1553074/fulllongmaxi formationorganic-rich shalegeochemical characteristicssedimentary environmentsichuan basin |
| spellingShingle | Licheng Yang Yi Hu Xinrui Yang Lianghua Zhang Wen Tang Dongxi Liu Huilin Li Qibing Wen Lin Xie Xingzhi Wang Jiahao Kang Zhidian Xi Ruiyu Guo Response of geochemical characteristics of organic-rich shale of Longmaxi formation to the sedimentary environment in the Neijiang-Rongchang area, Sichuan Basin, China Frontiers in Earth Science longmaxi formation organic-rich shale geochemical characteristics sedimentary environment sichuan basin |
| title | Response of geochemical characteristics of organic-rich shale of Longmaxi formation to the sedimentary environment in the Neijiang-Rongchang area, Sichuan Basin, China |
| title_full | Response of geochemical characteristics of organic-rich shale of Longmaxi formation to the sedimentary environment in the Neijiang-Rongchang area, Sichuan Basin, China |
| title_fullStr | Response of geochemical characteristics of organic-rich shale of Longmaxi formation to the sedimentary environment in the Neijiang-Rongchang area, Sichuan Basin, China |
| title_full_unstemmed | Response of geochemical characteristics of organic-rich shale of Longmaxi formation to the sedimentary environment in the Neijiang-Rongchang area, Sichuan Basin, China |
| title_short | Response of geochemical characteristics of organic-rich shale of Longmaxi formation to the sedimentary environment in the Neijiang-Rongchang area, Sichuan Basin, China |
| title_sort | response of geochemical characteristics of organic rich shale of longmaxi formation to the sedimentary environment in the neijiang rongchang area sichuan basin china |
| topic | longmaxi formation organic-rich shale geochemical characteristics sedimentary environment sichuan basin |
| url | https://www.frontiersin.org/articles/10.3389/feart.2025.1553074/full |
| work_keys_str_mv | AT lichengyang responseofgeochemicalcharacteristicsoforganicrichshaleoflongmaxiformationtothesedimentaryenvironmentintheneijiangrongchangareasichuanbasinchina AT yihu responseofgeochemicalcharacteristicsoforganicrichshaleoflongmaxiformationtothesedimentaryenvironmentintheneijiangrongchangareasichuanbasinchina AT xinruiyang responseofgeochemicalcharacteristicsoforganicrichshaleoflongmaxiformationtothesedimentaryenvironmentintheneijiangrongchangareasichuanbasinchina AT lianghuazhang responseofgeochemicalcharacteristicsoforganicrichshaleoflongmaxiformationtothesedimentaryenvironmentintheneijiangrongchangareasichuanbasinchina AT wentang responseofgeochemicalcharacteristicsoforganicrichshaleoflongmaxiformationtothesedimentaryenvironmentintheneijiangrongchangareasichuanbasinchina AT dongxiliu responseofgeochemicalcharacteristicsoforganicrichshaleoflongmaxiformationtothesedimentaryenvironmentintheneijiangrongchangareasichuanbasinchina AT huilinli responseofgeochemicalcharacteristicsoforganicrichshaleoflongmaxiformationtothesedimentaryenvironmentintheneijiangrongchangareasichuanbasinchina AT qibingwen responseofgeochemicalcharacteristicsoforganicrichshaleoflongmaxiformationtothesedimentaryenvironmentintheneijiangrongchangareasichuanbasinchina AT linxie responseofgeochemicalcharacteristicsoforganicrichshaleoflongmaxiformationtothesedimentaryenvironmentintheneijiangrongchangareasichuanbasinchina AT xingzhiwang responseofgeochemicalcharacteristicsoforganicrichshaleoflongmaxiformationtothesedimentaryenvironmentintheneijiangrongchangareasichuanbasinchina AT jiahaokang responseofgeochemicalcharacteristicsoforganicrichshaleoflongmaxiformationtothesedimentaryenvironmentintheneijiangrongchangareasichuanbasinchina AT zhidianxi responseofgeochemicalcharacteristicsoforganicrichshaleoflongmaxiformationtothesedimentaryenvironmentintheneijiangrongchangareasichuanbasinchina AT ruiyuguo responseofgeochemicalcharacteristicsoforganicrichshaleoflongmaxiformationtothesedimentaryenvironmentintheneijiangrongchangareasichuanbasinchina |