海南岛东南海域碎屑锆石年代学物源示踪及构造指示意义

为探索海南岛东南海域表层沉积物来源，揭示物源区主要地质构造演化事件，采用箱式取样法获取8个站位沉积物样品，进行锆石U-Pb定年.结果表明，773个有效年龄分布在33~3 205 Ma，主要年龄峰集中在燕山期(100 Ma、140 Ma和159 Ma)、印支期(242 Ma)和加里东期(439 Ma)，次要年龄峰集中在新元古代(776 Ma、965 Ma)和古元古代(1 836 Ma、2 487 Ma)，并零星保留太古宙基底年龄信息.少量变质锆石记录了加里东期和印支期强烈的变质事件.与潜在物源区对比分析表明，海南岛东南海域沉积物以约100 Ma的年龄峰值为识别标志，主要来源于海南岛.结合前人资料，本研究年龄频谱指示加里东期华夏武夷-云开造山带可延伸到海南岛，海西-印支期古特提斯洋的闭合及印支-华夏地块的碰撞导致其强烈的构造-岩浆-变质作用，燕山期受太平洋板块俯冲的影响发育多期次岩浆活动. 

Detrital Zircon Geochronology from Southeastern Sea of Hainan Island:Provenance Tracing and Tectonic Implications

In order to explore the provenance of surface sediments in the southeastern sea of Hainan Island and reveal the evolution history of major geological tectonic events in the provenance area, it used the box corer method to obtain sediment samples from 8 stations, and zircon U-Pb dating analyses were performed. The results show that 773 effective ages are distributed between 33 and 3 205 Ma, and the main age peaks are concentrated in the Yanshanian (100 Ma, 140 Ma and 159 Ma), Indosinian (242 Ma) and Caledonian (439 Ma). The secondary age peaks are concentrated in the Neoproterozoic (776 Ma, 965 Ma) and Paleoproterozoic (1 836 Ma, 2 487 Ma), and the Archean basement age information is scattered. A small number of metamorphic zircons records strong metamorphic events in the Caledonian and Indosinian. A comparative analysis with potential provenance area shows that the sediments in the southeastern sea of Hainan Island are identified by the age peak of about 100 Ma, which are mainly from Hainan Island. Combined with previous studies, the age spectrum in this study indicates that the Caledonian Wuyi-Yunkai orogenic belt in Cathaysia can extend to Hainan Island, the closure of the Paleo-Tethys Ocean and the collision between the Indosinian and Cathaysia blocks in Hercynian-Indosinian led to its strong tectonism-magmatism-metamorphism, and Hainan Island developed multiple magmatic activities due to the subduction of the Pacific plate in the Yanshanian.