安徽铜陵志留系—三叠系地层层序地层和微量元素地球化学:对沉积环境的约束  

Sequence Stratigraphy and Trace Element Geochemistry of Silurian to Triassic Strata in Tongling,Anhui Province: Constraints on Their Sedimentary Environment

作　　者：杜轶伦[1,2] 曹毅[2] 李大鹏[2] 高志伟[2] 

机构地区：[1]中国地质调查局发展研究中心,北京100037 [2]中国地质大学(北京)地球科学与资源学院,北京100083

出　　处：《现代地质》2014年第2期281-291,共11页Geoscience

基　　金：国家自然科学基金项目(40672045);中国地质调查局项目(资[2013]01-019-029)

摘　　要：在安徽铜陵地区广泛分布有志留系—三叠系沉积地层,它们与区内的层控矽卡岩矿床关系密切。作者对这些地层进行了层序地层学和微量元素地球化学研究,并在此基础上分析了铜陵地区古生代—中生代的沉积环境。层序地层学研究显示,铜陵地区在古生代—中生代期间发生了3次海平面变化事件,形成了3个沉积序列:(1)早志留世—晚泥盆世海退序列;(2)晚泥盆世—早二叠世海侵序列;(3)晚二叠世—早三叠世海退序列。微量元素地球化学研究表明,铜陵地区在古生代—中生代地层沉积过程中底层海水的物理化学条件(氧化还原条件)发生过3次明显的波动,并与3次海平面变化事件相对应。有意义的是,铜陵地区的大部分层控矽卡岩矿床都产在与后两次海平面变化事件相对应的地层中。The Silurian to Triassic strata of clastic sedimentary rocks and carbonates are widely distributed in the Tongling area,Anhui Province,East China,and closely associated with stratabound skarn deposits.This paper presents sequence stratigraphy and trace element geochemistry of the strata,and provides some constraints on their sedimentary environment.Sequence stratigraphical investigation shows occurrence of three events of sea level varying responsible for the formation of three sedimentary successions of regression through transgression to regression during the Paleozoic to Mesozoic period.These sedimentary successions include：（1 ）Early Silurian to Late Devonian regressive sequence,（2）Late Devonian to Early Permian transgressive sequence,and （3） Late Permian to Early Triassic regressive sequence.Trace element geochemistry analyses indicates existence of three evident variations in physicochemical conditions （especially oxidation-reduction conduction ）of the sea bottom water during the Paleozoic to Mesozoic sedimentary period in the Tongling area.These variations are cor-responded to the three events of sea level varying.It is significant that most of stratabound skarn deposits occur in the strata formed during the last two events of sea level varying.

关 键 词：志留系-三叠系沉积地层 层序地层 微量元素地球化学 沉积环境 安徽铜陵 

分 类 号：P588.2[天文地球—岩石学]