青海上二叠统—三叠系石关组和巴颜喀拉山群地层层序及其孢粉组合  

STRATIGRAPHY AND PALYNOLOGY OF THE UPPER PERMIAN-TRIASSIC SHIGUAN FORMATION AND BAYANHARASHAN GROUP IN QINGHAI,NORTHWEST CHINA

作　　者：冀六祥 彭辉平 欧阳舒[3] 罗伟[4] 古风宝[1] 刘锋[5] JI Liu-xiang;PENG Hui-ping;OUYANG Shu;LUO Wei;GU Feng-bao;LIU Feng(Qinghai Geological Survey Institute,Xining 810021;Consulting Center of Stratigraphy and Palaeontology,Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences,Nanjing 210008;Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences,Nanjing 210008;Shiyan Architectural Design Institute,Shiyan 442000;State Key Laboratory of Palaeobiology and Stratigraphy,Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Paleoenvironmeni,Chinese Academy of Sciences,Nanjing 210008)

机构地区：[1]青海省地质调查院,青海西宁810012 [2]中国科学院南京地质古生物研究所,地层古生物咨询中心,江苏南京210008 [3]中国科学院南京地质古生物研究所,江苏南京210008 [4]湖北省十堰市建筑设计研究院,湖北十堰442000 [5]中国科学院南京地质古生物研究所和生物演化与环境卓越创新中心,现代古生物学和地层学国家重点实验室,江苏南京210008

出　　处：《地层学杂志》2020年第4期411-427,共17页Journal of Stratigraphy

基　　金：现代古生物学和地层学国家重点实验室自主选题项目(Y826010111)资助。

摘　　要：2000年《中国地层典》将巴颜喀拉山群划分为下、中、上三个亚群(统),但未建组。本文回顾了青海省三叠系巴颜喀拉山群的研究历史和现状,在前人地质调查研究的基础上,对此群的地层分布和层序做了系统归纳、整理、补充和修正,明确了前人命名剖面并增补选层型。经数十年的研究,现已查明青海三叠系三个统(亚群)在北带、中带和南带的发育、分布情况,以下三叠统为主,中—上三叠统少量出现或断续分布。本文在巴颜喀拉山下亚群建立池塘组和昌马河组,中亚群建立甘德组,上亚群建立达日组,并分别指定它们的正层型、副层型及参考剖面。玛沁县昌马河地区三叠系产双壳类、菊石或珊瑚等化石,可作为区域地层对比的重要参考。主要根据孢粉组合,将原池塘群、布青山群和浩斗杂阔尔群都归于巴颜喀拉山群下亚群:新建的池塘组产出Lundbladispora-Cycadopites-Veryhachium孢粉组合,昌马河组产出Limatulasporites-Cycadopites-Tubermonocolpites-Micrhystridium组合。巴颜喀拉山群之下为乐平统(上二叠统)石关群,含有[虫筳]Palaeofusulina和腕足类Squamularia waagenii等海相动物化石,以及Klausipollenites schaubergerii-Jugasporites delasausei孢粉组合。本文建立石关组,将这套地层归入其中,并指定层型和参考剖面。The Bayanharashan Group in Qinghai,Northwest China was subdivided into the lower,middle and upper sections in"Stratigraphical Lexicon of China"published in 2000.However,formal names have not been assigned to these lithostratigraphic units by far.Based on the previous geological survey and a series of palynological studies,the authors attempt to review and improve the subdivision and correlation as well as age-designating by assigning clear stratotype and paratypes to these lithostratigraphic units.Investigation for the last decades has demonstrated that the Bayanharashan Group is dominated by the Lower Triassic deposits with sporadic Middle and Upper Triassic.It here is subdivided into the Lower Triassic(Chitang Formation and Changmahe Formation),the Middle Triassic(Gande Formation),and the Upper Triassic(newly proposed Dari Formation).The marine faunal fossils recovered from the Changmahe Formation in Maqin County could serve as a proxy for regional stratigraphic correlation.The previously named lithostratigraphic units,viz.the Chitang Group,the Buqingshan Group,and the Haodouzakuoer Group,are all assigned into the Lower Bayanharashan Subgroup because of their similarity in palynological composition.The Chitang Formation yields the Lundbladispora-Cycadopites-Veryhachium assemblage,while the Changmahe Formation yields the Limatulasporites-Cycadopites-Tubermonocolpites-Micrhystridium assemblage.A possible Late Permian palynological assemblage tentatively named as Klausipollenites schaubergerii-Jugasporites delasausei assemblage was found from the deposts previously ascribed to the lower part of the Bayanharashan Group.Here a new lithostratigraphic unit,the Shiguan Formation,is established to represent this set of strata.

关 键 词：三叠系 上二叠统 巴颜喀拉山群 石关组 孢粉 青海 

分 类 号：P534.46[天文地球—古生物学与地层学] P534.51[天文地球—地质学]