地质科学2017，Vol.52Issue(1)：230-241,12.DOI:10.12017/dzkx.2017.015
广西来宾蓬莱滩剖面G-L界线草莓状黄铁微晶粒径特征及其氧化还原意义
Framboidal microcryst size characteristics of pyrite and its redox significance across the G-L boundary in Penglaitan section, Laibin, Guangxi
摘要
Abstract
A mass extinction took place at the end of Guadalupian,seriously killing many species.For the causes of this extinction event,some researcher suggested that the marine anoxia was one of the major causes.However,there are few studies on this redox condition during the G-L transition period,lacking of direct evidence to support the relationship between ocean anoxia and mass extinction at the end of Guadalupian.Framboidal pyrite size distribution is one of the few reliable indicators of redox conditions of sedimentation water column.Since the microcrystal size is related with framboid pyrite size,its size distribution should be also a indicator of redox condition.In this paper,we study the microcrystal size distribution across the Maokou-Heshan Formations boundary in the Penglaitan section,so as to analyze the redox conditions of water column.The studied results show that the most microcrystallite size of Maokou and Heshan Formations range from 0.4 μm to 1.2 μm and has a narrow size variation,though some of the samples show a wider variation.At the Maokou Formation-Heshan Formation boundaries,the samples with a small size (average less than 0.7 μm) and a small the maximutn size (average less than 1.2 μm) intermittently occurs,likely indicating euxinic to anoxic environment.The average size of most samples from Maokou and Heshan Formations ranges from 0.7 μm to 1.0 μm with a maximum value less than 3.3 μm,probably indicating the dysoxic to oxic environment.In the Penglaitan section,the euxinic to anoxic layers is coincided with the mass extinction level at the G-L boundary,indicating a causal link between.Marine anoxia is probability one of the main causes of the end Guadalupian mass extinction.关键词
蓬莱滩剖面/G-L界线/黄铁矿草莓微晶/氧化还原条件/生物灭绝Key words
Penglaitan section/G-L boundary/Framboid pyritic microcrystal/Redox conditions/Mass extinction分类
天文与地球科学引用本文复制引用
韦雪梅,韦恒叶,邱振,江增光,白玛曲宗..广西来宾蓬莱滩剖面G-L界线草莓状黄铁微晶粒径特征及其氧化还原意义[J].地质科学,2017,52(1):230-241,12.基金项目
国家自然科学基金项目(编号:41302021)资助. （编号:41302021）
