安徽巢湖下三叠统含巢湖龙动物群地层微相特征及古环境  

Microfacies characteristics of the Lower Triassic containing Chaohusaurus fauna in Chaohu area,Anhui Province and its palaeoenvironment

作　　者：张钰莹[1,2] 江大勇[1] 付宛璐[1] 季承[3] 孙作玉[1] 

机构地区：[1]北京大学地球与空间科学学院,北京100871 [2]辽宁省地质矿产研究院,辽宁沈阳1100313 [3]中国科学院南京地质古生物研究所,江苏南京210008

出　　处：《古地理学报》2014年第5期761-768,共8页Journal of Palaeogeography：Chinese Edition

基　　金：国家自然科学基金重大国际合作研究项目(编号:40920124002);国家自然科学基金项目(编号:41372016);高等学校博士学科点专项科研基金(编号:20120001110072);现代古生物学和地层学国家重点实验室(中国科学院南京地质古生物研究所)开放基金(编号:123102)共同资助

摘　　要：安徽巢湖马家山剖面下三叠统南陵湖组中段上部—上段下部第598—630自然层中产出早三叠世巢湖龙动物群化石。通过对赋存巢湖龙动物群化石的第598—630自然层的微相类型和稳定碳氧同位素进行分析,揭示了该时期的沉积环境及其变化。在该段地层中共识别出4种微相类型,分别是红色—灰色瘤状厚层含骨针—双壳类生屑泥晶灰岩、灰色含生屑泥质泥晶灰岩、青灰色纹层状泥质泥晶灰岩和浅灰色含泥质泥晶灰岩,反映当时沉积环境从早到晚由外缓坡脚—深海盆地边缘渐变为外缓坡环境。稳定碳氧同位素分析表明,该段地层中δ13C值与δ18O值普遍偏低。综合微相、沉积相及稳定碳氧同位素特征,推断巢湖龙动物群生活在安静的外缓坡环境中,伴生的生物种类及数量相对比较稀少,海水温度总体偏高。The Early Triassic Chaohusaurus fauna was found at No.598-630 layers at the top of the Middle Member-the bottom of the Upper Member of the Nanlinghu Formation in Majiashan section of Cha-ohu area,Anhui Province.Based on the microfacies characteristics and the carbon and oxygen isotope a-nalysis,the sedimentary environment of the fossil beds where the Chaohusaurus fauna had occurred was studied.4microfacies types were recognized from the studied layers,which contained the red-grey thick nodular limestone with spicules-bivalves,the gray bioclastic-argillaceous micrite limestone,the gray lam-inated argillaceous micrite limestone,and the light gray micrite limestone,respectively.It was indicated that the sedimentary environment of the fossil beds was from the foot of the outer ramp-abyssal basin to the outer ramp.The values of the δ13C and δ18O are generally low in the whole of fossil beds.Combined with the above characteristics,it might be inferred that the Chaohusaurus fauna was living in the outer ramp zone with low-energy,less numbers and types of the biocoenose,and high seawater temperature.

关 键 词：下三叠统 南陵湖组 巢湖龙动物群 古环境 

分 类 号：P534.51[天文地球—古生物学与地层学] X144[天文地球—地质学]