{"title":"Organic matter enrichment model of Permian Capitanian-Changhsingian black shale in the intra-platform basin of Nanpanjiang basin","authors":"Haiquan Zhang, Junfeng Cao, Baofeng Lan, Yi Chen, Qian Zhang, Yupeng Men, Xintao Feng, Qian Yu","doi":"10.3389/feart.2024.1403575","DOIUrl":null,"url":null,"abstract":"The Permian Capitanian-Changhsingian black shale formed in intra-platform basins are the major source rocks in Southwest China. However, the depositional conditions and organic matter accumulation of these black shales are not well understood. In this study, geochemical characteristics comprise TOC, major, trace and REEs from sixty-two samples from the studied outcrop in Northern Nanpanjiang Basin, Southwest China are systematically investigated to determine silicon source, paleo-ocean productivity, and paleo-redox conditions to reveal their influence on organic matter enrichment under 3rd-order sequence. The Capitanian-Changhsingian black shale in the study area is the result of the combined effects of active extensional activity, high paleo-productivity maintained by volcanic activity, and dysoxic and anoxic conditions represented by biological extinction events. There are differences in the factors controlling organic matter accumulation in black shale at different stages. The controlling factors for the organic enrichment during Capitanian (SQ2) are the rapidly deepening water mass of extensional rifts and the high productivity induced by volcanic ash in the igneous provinces, as well as the global anoxic event represented by “negative carbon isotope shift.” The controlling factors during Changhsingian are the deepening of water mass under the reactivation of extensional rifts, resulting in a dysoxic environment, and the high productivity maintained by volcanic activity in South China. The Wuchiapingian black shale was formed under dysoxic conditions under the stagnation of extensional activity, and intermittent volcanic activity in South China maintained the high paleo-productivity level of the Wuchiapingian stage.","PeriodicalId":12359,"journal":{"name":"Frontiers in Earth Science","volume":null,"pages":null},"PeriodicalIF":2.0000,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Frontiers in Earth Science","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.3389/feart.2024.1403575","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
The Permian Capitanian-Changhsingian black shale formed in intra-platform basins are the major source rocks in Southwest China. However, the depositional conditions and organic matter accumulation of these black shales are not well understood. In this study, geochemical characteristics comprise TOC, major, trace and REEs from sixty-two samples from the studied outcrop in Northern Nanpanjiang Basin, Southwest China are systematically investigated to determine silicon source, paleo-ocean productivity, and paleo-redox conditions to reveal their influence on organic matter enrichment under 3rd-order sequence. The Capitanian-Changhsingian black shale in the study area is the result of the combined effects of active extensional activity, high paleo-productivity maintained by volcanic activity, and dysoxic and anoxic conditions represented by biological extinction events. There are differences in the factors controlling organic matter accumulation in black shale at different stages. The controlling factors for the organic enrichment during Capitanian (SQ2) are the rapidly deepening water mass of extensional rifts and the high productivity induced by volcanic ash in the igneous provinces, as well as the global anoxic event represented by “negative carbon isotope shift.” The controlling factors during Changhsingian are the deepening of water mass under the reactivation of extensional rifts, resulting in a dysoxic environment, and the high productivity maintained by volcanic activity in South China. The Wuchiapingian black shale was formed under dysoxic conditions under the stagnation of extensional activity, and intermittent volcanic activity in South China maintained the high paleo-productivity level of the Wuchiapingian stage.
期刊介绍:
Frontiers in Earth Science is an open-access journal that aims to bring together and publish on a single platform the best research dedicated to our planet.
This platform hosts the rapidly growing and continuously expanding domains in Earth Science, involving the lithosphere (including the geosciences spectrum), the hydrosphere (including marine geosciences and hydrology, complementing the existing Frontiers journal on Marine Science) and the atmosphere (including meteorology and climatology). As such, Frontiers in Earth Science focuses on the countless processes operating within and among the major spheres constituting our planet. In turn, the understanding of these processes provides the theoretical background to better use the available resources and to face the major environmental challenges (including earthquakes, tsunamis, eruptions, floods, landslides, climate changes, extreme meteorological events): this is where interdependent processes meet, requiring a holistic view to better live on and with our planet.
The journal welcomes outstanding contributions in any domain of Earth Science.
The open-access model developed by Frontiers offers a fast, efficient, timely and dynamic alternative to traditional publication formats. The journal has 20 specialty sections at the first tier, each acting as an independent journal with a full editorial board. The traditional peer-review process is adapted to guarantee fairness and efficiency using a thorough paperless process, with real-time author-reviewer-editor interactions, collaborative reviewer mandates to maximize quality, and reviewer disclosure after article acceptance. While maintaining a rigorous peer-review, this system allows for a process whereby accepted articles are published online on average 90 days after submission.
General Commentary articles as well as Book Reviews in Frontiers in Earth Science are only accepted upon invitation.