摘要：The Upper Triassic Chang 7 Member lacustrine organic-rich shale of the Yanchang Formation of the Ordos Basin is a significant hydrocarbon source rock containing abundant of tuff intervals ranging from millimeters to tens of centimeters thick. The present study relies upon petrographic and geochemical data of Chang 7 tuff intervals and organic-rich shale to consider fertilization of the lake surface by volcanic debris as a triggering mechanism of black shale sedimentation. Paleoproductivity proxies, including P/Al, Ni/Al, and Cu/Al, display elevated values in association with tuff intervals, suggesting increased productivity induced by volcanic nutrient seeding of the lake surface. Moreover, vertical variations of TOC mimic trends of paleoproductivity proxies, indicating that primary productivity was critical to organic carbon enrichment of the Chang 7 Member. Previous studies have postulated that lake bottom redox conditions were predominantly oxic-suboxic during deposition of the Chang 7 and that these deposits accumulated slowly, neither of which would have favored the export and preservation of organic matter in the absence of enhanced productivity. Accumulation of the organic-rich Chang 7 shale demonstrates the critical role that intensified primary productivity triggered by volcanism can play in the accumulation of carbonaceous sediment.

关键字：TRACE-METALS REDOX CONDITIONS ERLIAN BASIN BLACK SHALE PHOSPHORUS SEDIMENTS PRODUCTIVITY DEPOSITION CARBON ACCUMULATION

ISSN号：0008-4077

卷、期、页：卷: 56 期: 1 页: 47-59

发表日期：2019-01-01

影响因子：0.923000

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）,EI（工程索引）

发表期刊名称：Canadian Journal of Earth Sciences

参与作者：徐黎明,牛小兵

通讯作者：袁伟,李超正

第一作者：柳广弟

论文类型：期刊论文

论文概要：袁伟,柳广弟,徐黎明,牛小兵,李超正，Petrographic and geochemical characteristics of organic-rich shale and tuff of the Upper Triassic Yanchang Formation, Ordos Basin, China: implications for lacustrine fertilization by volcanic ash，Canadian Journal of Earth Sciences，2019，卷: 56 期: 1 页: 47-59

论文题目：Petrographic and geochemical characteristics of organic-rich shale and tuff of the Upper Triassic Yanchang Formation, Ordos Basin, China: implications for lacustrine fertilization by volcanic ash