摘要
虽然二叠系-三叠系界线附近的微生物岩是研究生态环境转折期海洋环境的热点素材,但以往所发现的实例都赋存于显生宙最大灭绝事件界线之上,还未报道过位于灭绝界线之下的微生物岩。川东北地区长兴组上部发育骨架礁层位之上的微生物丘,其中以尖山微生物丘最为典型,具三个生长旋回。根据微生物丘地层中所含牙形刺,和有孔虫,其时代为长兴晚期,处于大灭绝界线之下,其顶部距Hindeodus parvus带7.5m。碳同位素及微量元素分析揭示,从晚二叠世晚期开始,海洋生态环境条件的幕式不稳定性就已经显现并持续发展,导致生物危机也呈多阶段性特征。川东北晚二叠世微生物丘记录见证了重大地质转折期将至时生物与环境的相互作用关系。
The microbial rock around Permian and Triassic boundary has been a hot topic in researches of the marine environment during the ecological transition period. All the previous cases are discovered above mass extinction hori- zons of Phanerozoic Eon. , but nothing has ever been reported about microbial rocks located below mass extinction ho- rizons. The present study discusses the first findings on the late Changhsingian microbial mounds that develop on top of the skeletal reefs in the northeastern Sichuan, among which Jianshan microbial mounds are the most typical chara- cterized by three cyclical development stages. During the late Changhsing period, the microbial mound containing co- nodonts, fusulinids and foraminifera in strata, is located below the Permian - Triassic Mass Extinction Boundary, with its top approximately 7.5 m below the Hindeodus parvus zone. The analysis of δ13 C and trace element curves in- dicates that the unstable marine ecological environment has already taken shape and incessantly developed during the Late Permian, thus, the biotic crisis possesses a multi-phase feature. The development of late Changhsingian microbi- al mounds records and witnesses the interrelationship between the biology and environment as the crucial turning point in geological history is impending.
出处
《微体古生物学报》
CSCD
北大核心
2014年第3期229-242,共14页
Acta Micropalaeontologica Sinica
基金
国家自然科学基金(No.41272135)
油气重大专项(2008ZX05007-04)的资助
关键词
微生物丘
古海洋特征
生态危机
晚二叠世
川东北
microbial mounds, paleooceanographic features, eco-crisis, Late Permian, northeastern Sichuan, China
