塔里木盆地西北缘志留系兰多维列统塔塔埃尔塔格组的遗迹化石  

TRACE FOSSILS FROM THE LLANDOVERY(SILURIAN)TATAAIERTAGE FORMATION IN NORTHWESTERN TARIM BASIN,XINJIANG

作　　者：张小乐 季兴开 唐鹏[1] 王怿[1] ZHANG Xiao Le;JI Xing Kai;TANG Peng;WANG Yi(State Key Laboratory of Palaeobiology and Stratigraphy,Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences,Nanjing 210008;State Key Laboratory of Biogeology and Environmental Geology,China University of Geosciences,Wuhan 430074)

机构地区：[1]中国科学院南京地质古生物研究所,现代古生物学和地层学国家重点实验室,江苏南京210008 [2]中国地质大学(武汉),生物地质与环境地质国家重点实验室,湖北武汉430074

出　　处：《地层学杂志》2023年第4期478-492,共15页Journal of Stratigraphy

基　　金：中国科学院南京地质古生物研究所古生物学和地层学国家重点实验室(20192112);中国地质大学(武汉)生物地质与环境地质国家重点实验室(GBL22002);中国科学院战略性先导科技专项B类(XDB26000000);国家自然科学基金(42172003)共同资助。

摘　　要：遗迹化石在古代三角洲沉积环境判定及三角洲类型区分中应用广泛。本文对塔里木盆地西北缘志留系兰多维列统塔塔埃尔塔格组进行系统的沉积学和遗迹学研究,探讨不同沉积相带的遗迹化石构成与分布特征。研究结果表明,塔塔埃尔塔格组沉积于受河流影响的浪控三角洲体系中。在不同沉积相带,影响底栖生物分布的关键环境因素不同,因而遗迹化石构成与分布也表现出规律性变化。在前三角洲沉积中,遗迹化石以贫乏的Cruziana遗迹相分子(如Cruziana isp.、Gyrolithes isp.、Lockeia siliquaria和Neoeione isp.)为特征。在三角洲前缘远端沉积中,遗迹化石丰度和分异度均较高,包括Arenicolites isp.、Cochlichnus anguineus、Diplichnites isp.、Diplocraterion parallelum、Gyrochorte comosa、Lockeia siliquaria、Neoeione isp.、Planolites montanus、Rhizocorallium commune、Skolithos linearis、Teichichnus rectus和Treptichnus pedum,指示较为典型的Cruziana遗迹相。三角洲前缘近端沉积发育少量的Arenicolites curvatus、Arenicolites isp.和Skolithos linearis,以及指示机会性繁殖的Monocraterion isp.和Polykladichnus irregularis,代表相对贫乏的Skolithos遗迹相。本文研究表明,相分析结合遗迹化石构成和分布研究可为古代三角洲沉积环境的划分与识别提供可靠证据。Integrated analyses on sedimentary,lithological features of the strata and occurrence,composition of associated trace fossils provide invaluable information to facilitate the recognition and interpretation of ancient deltaic deposition.Here we conduct sedimentary and systematic ichnology studies on the Llandovery(Silurian)Tataaiertage Formation at the Renyinggou Section,Kalpin area,northwestern Tarim Basin.The results suggest that the Tataaiertage Formation was deposited in a wave-dominated,fluvial-influenced deltaic setting.The variation of major factors controlling the distribution of benthic fauna among different subenvironments have led to differential distribution and composition patterns of trace fossils.The prodelta facies are characterized by a trace fossil assemblage in low diversity and abundance,including Cruziana isp.,Gyrolithes isp.,Lockeia siliquaria and Neoeione isp.,constituting an impoverished expression of the Cruziana ichnofacies.Ichnofossils in the distal delta-front facies show higher diversity and abundance,including Arenicolites isp.,Cochlichnus anguineus,Diplichnites isp.,Diplocraterion parallelum,Gyrochorte comosa,Lockeia siliquaria,Neoeione isp.,Planolites montanus,Rhizocorallium commune,Skolithos linearis,Teichichnus rectus and Treptichnus pedum,resembling the archetype of the Cruziana ichnofacies.The proximal delta-front is characterized by dwelling traces of low diversity such as Arenicolites curvatus,Arenicolites isp.and Skolithos linearis,and sometimes opportunistic ichnospecies,including Monocraterion isp.and Polykladichnus irregularis,suggesting an impoverished Skolithos ichnofacies.

关 键 词：相分析 三角洲沉积 遗迹化石 兰多维列统(志留系) 遗迹相 

分 类 号：P534.43[天文地球—古生物学与地层学]