琼东北八所组ESR年龄及其构造意义  

ESR DATING OF THE BASUO FORMATION IN THE NORTHEASTERN HAINAN ISLAND AND ITS TECTONIC SIGNIFICANCE

作　　者：夏蒙蒙 王超群[1] 胡道功[1,2] 赵希涛 贾丽云[1,2] 吴环环[4] 吕同艳 XIA Mengmeng;WANG Chaoqun;HU Daogong;ZHAO Xitao;JIA Liyun;WU Huanhuan;LYU Tongyan(Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing 100081,China;Key Laboratory of Neo-tectonic Movement&Geo-hazard,Ministry of Natural Resources,Beijing 100081,China;Institute of Geology and Geophysics,Chinese Academy of Geological Sciences,Beijing 100029,China;Geological Bureau of Shenzhen,Shenzhen 518023,China)

机构地区：[1]中国地质科学院地质力学研究所,北京100081 [2]自然资源部新构造运动与地质灾害重点实验室,北京100081 [3]中国科学院地质与地球物理研究所,北京100029 [4]深圳市地质局,深圳518023

出　　处：《地质力学学报》2019年第2期257-266,共10页Journal of Geomechanics

基　　金：中国地质调查局项目(DD20190306;DD20160269)

摘　　要：八所组是琼东北晚第四纪一个重要地层单位,同时也是河流Ⅱ级阶地(T2)的主要沉积地层,其形成年代对该区域晚第四纪以来的古环境演化及地壳运动的研究有着重要意义。为了限定其形成时代,文章采取ESR的方法,对广泛分布于琼东北珠溪河及古三江河一带的八所组地层进行了系统的测年。结果表明:该套地层形成于晚更新世中晚期(64.36 ka～18.40 ka BP);沉积时代对应末次冰期MIS4～MIS2阶段;河流的下切与T2阶地的形成,一定程度上反映了该时期琼东北海平面的频繁波动及地壳的间歇性抬升;此外,分布于现代海岸风沙强烈作用地带的老红砂与八所组属同期异相的风成堆积,应与八所组地层加以区分。The Basuo Formation is an important stratigraphic unit in late quaternary and forms the main sedimentary formation of the second-level terrace(T2)in northeastern Hainan Province.Its formation age is of great significance to the study of paleoenvironmental evolution and crustal movement in the study area since late quaternary.In order to precisely define the age of this formation,we conducted a systematic research of the Basuo Formation distributed in Zhuxi River and Gusanjiang River in northeastern Hainan by using the method of Electron Spin Resonance(ESR)and acquired the geochronological data.The results show that the Basuo Formation was formed during 64.36~18.40 ka BP,and the sedimentary age corresponds to the last glacial stage of MIS4~MIS2;The river incision and the formation of T2 terrace,to some extent,reflect the frequent fluctuation of sea level and the intermittent uplift of crust in the northeast of Hainan during this period;moreover,the old red sands in the strong sandstorm action zone of modern coasts is the aeolian accumulation of contemporaneous and heterogeneous with the Baduo formation,which should be distinguished from the Baduo formation.

关 键 词：八所组 ESR 沉积环境 晚更新世 琼东北 

分 类 号：P534.63[天文地球—第四纪地质学]