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Petroleum Science >2019,??Issue 2:??252-266 DOI: https://doi.org/10.1007/s12182-018-0293-3

Geochemistry of upper Permian siliceous rocks from the Lower Yangtze region, southeastern China: implications for the origin of chert and Permian ocean chemistry Open?Access

文章信息

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作者：Zhi?Wei Liao, Wen?Xuan Hu, Xiu?Gen Fu and Zhong?Ya Hu
作者單位：

State Key Laboratory of Coal Mine Disaster Dynamics and Control, College of Resources and Environmental Science, Chongqing University, Chongqing 400044, China; Shandong Provincial Key Laboratory of Depositional Mineralization and Sedimentary Mineral, Shandong University of Science and Technology, Qingdao 266590, Shandong, China; Key Laboratory of Sedimentary Basin and Oil and Gas Resources, Ministry of Land and Resources, Chengdu 610081, China; State Key Laboratory of Palaeobiology and Stratigraphy (Nanjing Institute of Geology and Palaeontology, CAS), Nanjing 210008, Jiangsu, China,State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Institute of Energy Sciences, Nanjing University, Nanjing 210023, Jiangsu, China,Key Laboratory of Sedimentary Basin and Oil and Gas Resources, Ministry of Land and Resources, Chengdu 610081, China and State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Institute of Energy Sciences, Nanjing University, Nanjing 210023, Jiangsu, China

投稿時(shí)間：2018-07-27
引用方式：Liao, ZW., Hu, WX., Fu, XG. et al. Pet. Sci. (2019) 16: 252. https://doi.org/10.1007/s12182-018-0293-3

文章摘要

The Permian Chert Event is of great significance to understanding the geological evolution of the entire Permian; however, the origin of widespread chert formation is debated. We report new geochemical data from deep-marine siliceous rocks of the upper Permian Da-long Formation, Lower Yangtze region, southeastern China. Their geochemical results show that these thin-bedded siliceous rocks have a clear biologic origin, with rare to no evidence of hydrothermal influence. The values of Al/(Al + Fe + Mn) and Eu/Eu* are 0.60–0.84 (mean = 0.72) and 0.45–1.08 (mean = 0.77), respectively, and Mn/Ti ratios are relatively low (mean = 0.72). The correlations of LaN/ CeN, LaN/ YbN, and Fe2O3/ TiO2 with Al2O3/(Al2O3 + Fe2O3), along with the Ce anomaly, indicate that the Da-long siliceous rocks were deposited at a transitional zone between a continental margin and the open ocean; i.e., relatively close to terrestrial sediment input and far from hydrothermal activity. The accumulation of chert is related to its unique paleogeographic location in an equatorial setting with many submarine paleo-highlands. Intense upwelling and frequent local volcanism are the main factors that promoted the development of siliceous rocks in the studied area. Ocean acidification triggered by large-scale volcanism (Large Igneous Province) during the late Permian led to extensive silica precipitation and preservation.

關(guān)鍵詞

    Lower Yangtze region, Da-long Formation, Siliceous rock, Biological chert, Volcanism