南海北部扩张的地表过程响应:来自海南岛五指山的磷灰石裂变径迹年龄证据  

Surface process responses to the expansion of the northern South China Sea:Age evidence of apatite fission tracks from Wuzhi Mountains,Hainan Island

作　　者：史军华 韩帅 杜建军[1] 韩建恩[1] 孙东霞 胡道功[1] SHI Junhua;HAN Shuai;DU Jianjun;HAN Jianen;SUN Dongxia;HU Daogong(Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing 100081,China;China University of Geoscience,Beijing 100083,China)

机构地区：[1]中国地质科学院地质力学研究所,北京100081 [2]中国地质大学,北京100083

出　　处：《地质学报》2024年第2期421-432,共12页Acta Geologica Sinica

基　　金：中国地质科学院地质力学研究所基本科研业务费项目(编号所科研56)资助的成果。

摘　　要：海南岛是南海地块的重要组成部分,其构造演化很大程度上能够反映整个南海的构造活动特征。新生代,海南岛在新构造运动作用下,断块差异升降比较明显,形成了大致以王五-文教断裂为界,北为沉降区,南为断隆区的构造格局。对断隆区隆升过程的研究能够帮助揭示海南岛新构造活动历史,但至今为止,琼中南山地隆升的原因和时限仍存在争议。为了厘清海南岛中部的剥露隆升事件,本文选择琼中南地区海拔最高、高差最大的五指山为研究区,采集8组高程岩石样品,高程范围为203.55~1153.52 m。对采集的样品进行了磷灰石裂变径迹测试和热历史模拟分析,结果表明海南岛五指山地区新生代主要经历了两期快速隆升剥露。第一期为渐新世—中新世(32~17 Ma):隆升速率较快,此时期太平洋板块向欧亚板块俯冲后撤,南海正经历第二次扩张,使得海南岛拉张,活动强烈,造成琼中山地区快速隆升,直到中中新世转为缓慢隆升。第二期为中新世末期(5 Ma)的快速剥蚀隆升阶段:南海扩张已经结束,随着菲律宾板块俯冲亚洲板块,南海北部陆缘整体处于加速热沉降阶段,且全球气候变化加快,造成了海南岛广泛的隆起和加速剥蚀。Hainan Island is an important part of the South China Sea block,and its tectonic evolution can largely reflect the tectonic activity characteristics of the entire South China Sea.During the Cenozoic period,under the neotectonic movement of Hainan Island,the differential rise and fall of fault blocks was relatively obvious,forming a tectonic pattern roughly bounded by the Wangwu-Wenjiao fault,with the subsidence area to the north and the fault-uplift area to the south.Research on the uplift process of the faulted uplift area can reveal the history of neotectonic activity in the Hainan Island,but so far,the cause and timing of the uplift of the southern Qiongzhong Mountains are still controversial.In order to clarify the exfoliation and uplift events in the central part of Hainan Island,this paper selected the Wuzhi Mountain with the highest elevation and the largest elevation difference in the southern Qiongzhong area as the study area,and collected 8 sets of rock elevation samples in this area,with an elevation range of 203.55~1153.52 m.A large number of apatite fission track tests and thermal history simulation analysis were carried out on the collected samples.The results show that the Cenozoic in the Wuzhi Mountain area of the Hainan Island mainly experienced two periods of rapid uplift and exfoliation.The first period is from Oligocene to Miocene(32~17 Ma)when the uplift rate was relatively fast.During this period,the Pacific plate subducted and retreated to the Eurasian plate,and the South China Sea experienced the second expansion,making Hainan Island stretched.The activity was intense,causing the Qiongzhongshan area to uplift rapidly until it turned into a slow uplift during the Middle Miocene.The second stage is the stage of rapid denudation and uplift at the end of the Miocene(5 Ma)when the expansion of South China Sea had ended.With the subduction of the Asian plate under the Philippine plate,the entire northern continental margin of South China Sea was in the stage of accelerated thermal subsidence,and

关 键 词：裂变径迹 新生代构造运动 隆升与剥露历史 海南岛 五指山 

分 类 号：P736[天文地球—海洋地质] P597.3[天文地球—海洋科学]