从构造热事件探讨湖南志留纪沉积时限兼论盆地演化特征  

Discussion on Silurian sedimentary duration and the basin evolution features from tectonic heat events

作　　者：刘南 高翔 艾国梁 贺良 

机构地区：[1]湖南省地质调查院,长沙410116

出　　处：《地质找矿论丛》2017年第3期428-433,共6页Contributions to Geology and Mineral Resources Research

基　　金：国家自然科学基金重点基金资助项目(编号:41030315);中国地质调查局项目(编号:1212011121108)联合资助

摘　　要：湖南地区志留纪的沉积时限一直以来争议颇多,笔者通过对该区沉积特征及层序地层、构造运动分析发现:小溪峪组属于一套有障壁海岸浅海细碎屑沉积,是海水由南东向北西退却期的沉积响应,属于早期高水位体系域;泥盆系云台观组属一套海侵型的海相陆源碎屑岩沉积,从野外的界面特征分析云台观组为一套开阔海岸受波浪作用明显的以石英砂为主体的沉积物,属于广西运动之后由东南向北西形成的海侵过程的沉积响应。小溪峪组与云台观组二者所属沉积盆地环境和演化不同,其界面属于Ⅰ型层序界面,不整合接触。广西运动导致的江南造山带的隆起在430Ma左右结束,志留纪沉积盆地应大部分消亡,由此认为志留纪沉积盆地接受的沉积物时间也应在相对应时段中,小溪峪组在湖南地区不存在晚志留纪沉积物。The sedimentary duration of Silurian has been a lot of controversy.Analysis of sedimentary characteristics and sequence stratigraphy and tectonic movement in this area shows that Xiaoxiyu Formation is of barrier sea coast neritic clastic deposition and is the sedimentary response of seawater retreating from the southeast to northwest belonging to the early stage of highstand system tract.The Devonian Yuntaiguan Formation is terrigeneous clastics during transgression.Based on analysis of the interface characteristics in the field,the author consider that devonian Yuntaiguan Formation is of an open coastal quartz sand-dominated sediment obviously affected by wave action.It is a sedimentary response of transgression from the southeast to the northwest after Guangxi movement.The two are different in sedimentary basin environment and evolution.They contact unconformably with interface of typeⅠsequence boundary（SB1）.The uplift of the Jiangnan orogenic belt caused by Guangxi movement ended about 430 Ma age when most of Silurian Sedimentary Basin closed.the sedimentary time of the basin should also be in the corresponding period.There is no late Silurian sedimentation in Xiaoxiyu Formation in Hunan.

关 键 词：小溪峪组 沉积时限 盆地演化 志留纪 湖南省 

分 类 号：P534.43[天文地球—古生物学与地层学] P539.2[天文地球—地质学]