云南罗平生物群埋藏环境初步研究:来自沉积构造的证据  

Preliminary Study of Taphonomic Environment of Luoping Biota:Evidence from sedimentary structures

作　　者：白建科[1,2] 张启跃[1] 尹福光[1] 谢韬[1] 周长勇[1] 吕涛[1] 冯静[1] 

机构地区：[1]中国地质调查局成都地质调查中心,成都610081 [2]中国地质科学院,北京100037

出　　处：《沉积学报》2010年第4期762-767,共6页Acta Sedimentologica Sinica

基　　金：中国区域地质调查项目(编号:1212010610211)资助

摘　　要：罗平生物群产于云南省罗平县大凹子村中三叠统关岭组二段中,是以海生鱼类为主,还伴生有海生爬行类、棘皮类、双壳以及植物化石。产化石层位以灰黑色薄层泥晶灰岩为主,水平纹层、波状层理、同生变形构造(滑塌构造、包卷层理)、正粒序、虫迹等沉积构造发育。对这些沉积构造进行研究来探讨罗平生物群的沉积与埋藏环境,结果表明:罗平生物群沉积环境为碳酸盐台地内部具远端变陡坡折的浅海深水盆地,水体相对较深,处于间隙性缺氧状态,有效地阻止了生物化石的腐烂分解;远端变陡缓坡部分发育的同沉积变形构造指示了环境的突发性变化,引发了生物的大量死亡并被迅速埋藏。The Luoping Biota is contained in the Member Ⅱ of the Ainsian Guanling Formation at Dawazi Village,Luoping County,Yunnan Province,China.It is characterized by abundant well-preserved marine ichthyofauna,associated with marine reptiles,echinoderms,crustaceans,bivalves and plant fossils.The strata bearing the Luoping Biota are dominated by gray black thin bedded micrite as well as a large number of sedimentary structrues,such as horizontal laminae,wavy bedding,deformation structures（slump structures,convolute bedding） and trace fossils and so on.This paper aims to study the sedimentary environment and taphonomy of the Luoping Biota.The result shows that the sedimentary environment of Luoping Biota is a deep water basin with distally steepened ramp on the platform.The sea water in this basin was relatively quiet with intermittent reducing condition which effectively prevented the degradation of organisms.The sedimentary deformation structures on distally steepened ramp indicate that the environment was changed suddenly,which led to the demise and the rapid burial of the biota.

关 键 词：罗平生物群 沉积构造 远端变陡缓坡 深水盆地 埋藏环境 

分 类 号：P512.2[天文地球—地质学]