Petrologic and geochemical evidence for the formation of organic-rich siliceous rocks of the Late Permian Dalong Formation, Lower Yangtze region, southern China

doi:10.1016/j.marpetgeo.2019.02.005

CORC > 南京地质古生物研究所 > 中国科学院南京地质古生物研究所 > 中国科学院南京地质古生物研究所

	Petrologic and geochemical evidence for the formation of organic-rich siliceous rocks of the Late Permian Dalong Formation, Lower Yangtze region, southern China
	Liao, Zhiwei 1,2,3; Hu, Wenxuan 4; Cao, Jian 4; Wang, Xiaolin 4; Hu, Zhongya 4
刊名	MARINE AND PETROLEUM GEOLOGY
	2019-05
卷号	103 页码:41-54
关键词	Organic matter Enrichment Anoxia Upwelling Volcanism
ISSN号	0264-8172
DOI	10.1016/j.marpetgeo.2019.02.005
英文摘要	Black shales are economically and scientifically important because they are commonly associated with high-quality hydrocarbon source rocks and metal accumulations formed during periods of abrupt environmental change. Organic-rich siliceous rocks of the Late Permian Dalong Formation developed extensively within Middle Upper Yangtze region (western Yangtze platform); however, the formation mechanism of its formation in the Lower Yangtze region (eastern Yangtze platform) remains a subject of debate due to a lack of outcrop exposure. Petrologic, mineralogic, and geochemical data are presented for three sections of the Dalong Formation within the Lower Yangtze region. Geochemical ratios including V/(V + Ni), V/Cr, Ni/Co, U/Th, and V/Sc suggest that the Dalong Formation was deposited in an oxygen-poor environment. The elevated concentration of Mo (> 100 ppm) further suggests that free H2S existed in the bottom water, which was favorable for the accumulation of large amounts of organic matter. Mo/TOC ratios reveal that water flow in the Lower Yangtze Basin was moderately to strongly restricted during deposition of the Dalong Formation. Flow within the upper middle parts of the Yangtze Basin was also restricted, suggesting that northern marginal basins on the Yangtze Platform formed part of a single ocean during the Late Permian (i.e., Changhsingian). Cherts of the Dalong Formation reflect high primary productivity, similar to that of modern-day upwelling zones, which increased the amount of organic matter. These results, combined with previous work, suggest that the long-term oxygen-poor conditions during deposition of the Dalong Formation were caused by restricted water circulation in a unique paleogeographic environment characterized by low latitude and submarine paleo-highlands. Such settings of low latitude characterized by tropical climate favored the growth of siliceous zooplankton in the zones with submarine paleo-highlands having created topographic barriers to water circulation. Restricted bottom-water flow and oceanic anoxia during the Late Permian were likely the main controls on the accumulation of organic-rich rocks. Elevated nutrient levels caused by frequent oceanic upwelling along the western margin of the South China Craton and global volcanism at this time facilitated siliceous organism productivity.
WOS研究方向	Geology
语种	英语
出版者	ELSEVIER SCI LTD
WOS记录号	WOS:000466617700004
内容类型	期刊论文
源URL	[http://ir.nigpas.ac.cn/handle/332004/22373]
专题	中国科学院南京地质古生物研究所
作者单位	1.Chongqing Univ, Coll Resources & Environm Sci, State Key Lab Coal Mine Disaster Dynam & Control, Chongqing 400044, Peoples R China; 2.Chengdu Univ Technol, State Key Lab Oil & Gas Reservoirs Geol & Exploit, Chengdu 610059, Sichuan, Peoples R China; 3.Chinese Acad Sci, Nanjing Inst Geol & Palaeontol, State Key Lab Palaeobiol & Stratig, Nanjing 210008, Jiangsu, Peoples R China; 4.Nanjing Univ, Inst Energy Sci, Sch Earth Sci & Engn, State Key Lab Mineral Deposits Res, Nanjing 210023, Jiangsu, Peoples R China
推荐引用方式 GB/T 7714	Liao, Zhiwei,Hu, Wenxuan,Cao, Jian,et al. Petrologic and geochemical evidence for the formation of organic-rich siliceous rocks of the Late Permian Dalong Formation, Lower Yangtze region, southern China[J]. MARINE AND PETROLEUM GEOLOGY,2019,103:41-54.
APA	Liao, Zhiwei,Hu, Wenxuan,Cao, Jian,Wang, Xiaolin,&Hu, Zhongya.(2019).Petrologic and geochemical evidence for the formation of organic-rich siliceous rocks of the Late Permian Dalong Formation, Lower Yangtze region, southern China.MARINE AND PETROLEUM GEOLOGY,103,41-54.
MLA	Liao, Zhiwei,et al."Petrologic and geochemical evidence for the formation of organic-rich siliceous rocks of the Late Permian Dalong Formation, Lower Yangtze region, southern China".MARINE AND PETROLEUM GEOLOGY 103(2019):41-54.