摘要：The lacustrine Chang 7 organic-rich shale of the Upper Triassic Yanchang Formation is a very important hydrocarbon source rock and contains high total organic carbon content (average = 5.54 wt.%). Previous studies suggest that deposits of the Chang 7 accumulated slowly under dominantly oxic-suboxic bottom-water conditions occasionally interrupted by the establishment of anoxic conditions. However, questions remain regarding the role of palaeoproductivity in accumulation of the Chang 7 organic matter. Palaeoproductivity indicators, including P/Al, Ni/Al, Cu/Al, and Zn/Al, suggest that the deposition of the Chang 7 period was accompanied by high primary productivity level. Furthermore, productivity appears to have been highest in the middle and south-east region of the lake, diminishing to the north-east, the north-west, and the south-west. Elevated productivity resulted in the flux of large amounts of organic matter to the lake floor. Intermittent anoxic bottom-water conditions caused by oxygen consumption during organic matter degradation favoured enhanced preservation of organic matter even under oxic-suboxic water column. Low sedimentation rate made the organic matter in sediments avoid dilution of terrigenous clastics, which made it play a positive role in the accumulation of organic matter.

关键字：Chang 7 Member nutrients organic matter accumulation mechanism redox conditions sedimentation rate

ISSN号：0072-1050

卷、期、页：卷: 55 期: 4 页: 3139-3156

发表日期：2020-04-01

影响因子：1.594900

期刊分区（SCI为中科院分区）：四区

收录情况：SCIE（科学引文索引网络版）

发表期刊名称：GEOLOGICAL JOURNAL

参与作者：Zhou, Xiaoxing,Xu, Liming

通讯作者：袁伟,Li, Chaozheng

第一作者：柳广弟

论文类型：期刊论文

论文概要：袁伟,柳广弟,Zhou, Xiaoxing,Xu, Liming,Li, Chaozheng，Palaeoproductivity and organic matter accumulation during the deposition of the Chang 7 organic-rich shale of the Upper Triassic Yanchang Formation, Ordos Basin, China，GEOLOGICAL JOURNAL，2020，卷: 55 期: 4 页: 3139-3156

论文题目：Palaeoproductivity and organic matter accumulation during the deposition of the Chang 7 organic-rich shale of the Upper Triassic Yanchang Formation, Ordos Basin, China