江西石城通天寨地质公园晚白垩世河口组碎屑锆石年龄及地质意义  

Geochronology of detrital zircons and its geological significance for the Hekou Formation of Late Cretaceous in Tongtianzhai, Shicheng County, Jiangxi Province

作　　者：毛晓长[1] 董颖[2] 胡昆 寇晓虎[3] 杨宏斌[2] 谢长瑜 汪凡[4] 马逸麟[4] MAO Xiaochang;DONG Ying;HU Kun;KOU Xiaohu;YANG Hongbin;XIE Changyu;WANG Fan;MA Yilin(China Geological Survey,Beijing 100037,China;China Institute of Geological Environment Monitoring,Beijing 100001,China;China University of Geosciences,Wuhan 430074,Hubei,China;Geological Survey of Jiangxi Province,Nanchang 330030,Jiangxi,China)

机构地区：[1]中国地质调查局,北京100037 [2]中国地质环境监测院,北京100081 [3]中国地质大学(武汉)地质调查研究院,湖北武汉430074 [4]江西省地质调查研究院,江西南昌330030

出　　处：《地质通报》2018年第2期411-420,共10页Geological Bulletin of China

基　　金：中国地质调查局项目<全国重要地质遗迹调查>(编号:121201014000150018)和<全国系列基础地质综合编图>(编号:121201004000150013)

摘　　要：江西石城通天寨地区位于南丰-会昌中—新生代盆地带内,区内出露的上白垩统河口组主要为一套陆相冲积扇红色碎屑岩系,自下向上分为3段,分别代表扇根→扇中→扇缘沉积相。通过岩相古地理分析,其物源分别来自北西方向和南东方向的2个隆起蚀源区。采用碎屑锆石LA-ICP-MS测年方法,获得河口组2件样品的111组和108组碎屑锆石有效U-Pb年龄,其年龄谱主要存在104~137Ma、400~418Ma、750~752Ma、1854~1895Ma四个年龄峰值,揭示出蚀源区曾存在4次主要的构造热事件。1854~1895Ma和750~752Ma热事件可能分别是对哥伦比亚和罗迪尼亚超大陆聚散的响应;400~418Ma是对华夏造山带洋陆转换的响应;104~137Ma是古太平板块西缘转化为活动陆缘对华南东缘的构造岩浆热事件的响应。Tongtianzhai is located in the Nanfeng-Huichang Mesozoic-Cenozoic basin of Shicheng County,Jiangxi Province.The Late Cretaceous Hekou Formation is mainly composed of a red clasolite series in continental alluvial fan,and can be divided into three sections,representing fan root,fan middle and fan margin sedimentary facies from bottom upwards.And the provenance was derived from two uplift erosion areas from the NW and SE direction based on the lithofacies paleogeographic analysis.The authors obtained 111 and 108 detrital zircon U-Pb ages from two samples in the Hekou Formation respectively using the LA-ICP MS geochronology.There are four age peaks in age spectrum.i.e.,104~137Ma,400~418Ma,750~752Ma,and 1854~1895Ma,which show four main tectonic thermal events in the source area.Thermal events in 1854~1895Ma and 750~752Ma may be the response to the meeting and parting of the Columbia and Rodinia supercontinent;thermal event in 400~418Ma was a response to the ocean-continent conversion of Huaxia orogenic belt;thermal event in 104~137Ma was a response of the tectonic magma event on the eastern margin of South China Plate resulting from the transformation of the western margin of the paleo Pacific plate into an active continental margin.

关 键 词：晚白垩世 河口组 碎屑锆石年龄谱 构造热事件 江西石城 

分 类 号：P534.53[天文地球—古生物学与地层学] P597.3[天文地球—地质学]