青海省北祁连山三叠纪孢粉和疑源类及其地层意义  

TRIASSIC SPOROPOLLEN AND ACRITARCHS FROM NORTHERN QILIAN MOUNTAIN(QINGHAI)AND THEIR STRATIGRAPHICAL SIGNIFICANCE

作　　者：冀六祥 罗伟 刘锋[3,4] 欧阳舒[3] 

机构地区：[1]青海省地质调查院,青海西宁810012 [2]湖北十堰市建筑设计研究院,湖北十堰442003 [3]中国科学院南京地质古生物研究所,江苏南京210008 [4]中国科学院资源地层学与古地理学重点实验室,江苏南京210008

出　　处：《地层学杂志》2015年第4期367-379,共13页Journal of Stratigraphy

基　　金：国家自然科学基金青年基金(No.41102001);中国科学院知识创新工程项目(No.KZCX2-EW-120)资助

摘　　要：青海省北祁连山小区(位于北祁连山南坡)三叠纪地层中发现丰富的孢粉化石,与不少疑源类共存,为探讨该地区三叠纪地层的沉积环境,确定其组级地层的地质时代,提供了有力证据。考虑到本小区如再沿用甘肃三叠纪纯陆相地层的一套名称,如西大沟群(组)、南营儿群等,已不太合适,所以建议用大檫汗沟群代表这套海陆交互相的三叠纪地层,下辖新定义的3个地层组。孢粉组合由下至上的序列为:下三叠统赛尔贡切组(T1s)下段Apicalatisporis-Cordaitina-Schizospori组合,上段的Aratisporites-Klausipollenites-Micrhystridium组合,中三叠统柯柯里组(T2k)的Verrucosisporites-Triadispora-Trematosphaeridium组合,上三叠统黑沟河组(T3h)下段的Aratrisporites-Ovalipollis-Micrhystridium组合,上段的Baculatisporites-Aratrisporites-Pinites-Dictyosphaera-Quadrisporites组合,这些组合可与国内外一些已知孢粉组合进行对比。同时探讨了本区三叠纪的沉积环境,指出并非纯陆相产物,而属海陆交互相沉积,孢粉组合/植物群反映当时气候温暖潮湿。Abundant spores,pollen grains,and acritarchs have been recovered from Triassic rocks in northern Qilian Mountains of Qinghai Province.The new paleontological data provide reliable information about the paleoenvironments and geological ages of the host strata.Considering their distinct lithostratigraphy and mixed marine-terrestrial environments,it is inappropriate to refer these Triassic strata to stratigraphic units（e.g.,the Xidagou Group/Formation and Nanying＇er Group）developed for exclusively terrestrial deposits in Gansu Province.Instead,the authors propose several new stratigraphical units for the mixed marine-terrestrial facies in the study area,including the Dachahangou Group consisting of,in ascending order,the Saiergongqie,Kekeli,and Heigouhe formations,which also have distinct sporopollen and acritarch assemblages.The lower member of the Saiergongqie Formation yields the ApiculatissporisCordaitina-Schizosporis Assemblage,and the upper member yields the Aratrisporites-KlausipollenitesKlausipollentes-MicrhystridiumAssemblage.The Kekeli Formation yields the Verrucosisporites-Triadispora-Trematosphaeridium Assemblage.The lower member of the Heigouhe Formation yields the Aratrisporites-Ovalipollis-Micrhystridium Assemblage,and the upper yields the Baculatisporites-AratrisporitesPinites-Dictosphaera Assemblage.

关 键 词：生物地层 孢粉 疑源类 三叠纪 北祁连山 青海 

分 类 号：P534.51[天文地球—古生物学与地层学]