U-Pb dating of zircon from the bed parallel anatectic granitic intrusion in the Baoban group in Hainan Island and the tectonic implication  

作　　者：DING Shijiang1, HU Jianmin2, SONG Biao3,4, CHEN Mulun1, XIE Shengzhou1 & FAN Yuan1 1. Geological Surveying Institute of Hainan, Haikou 570206, China 2. Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China 3. Beijing Center of SHRIMP, Beijing 100037, China 4. Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China 

出　　处：《Science China Earth Sciences》2005年第12期2092-2103,共12页中国科学（地球科学英文版）

基　　金：This research was supported by the Project for Hundred Talent Youth of the Ministry of Land and Resources of China;the National Natural Science Foundation of China(Grant No.40272097).

摘　　要：The petrological and geochemical features of the bed parallel granitic intrusion in the Pre-Cambrian Baoban group in Hainan Island attest to the anatexis origin of the granites. U-Pb dating analyses of zircons from the anatectic granite and the biotite two-feldspar gneiss in the Baoban group, using SHRIMP II in the Beijing Ion-probe Center, acquire 206Pb/238U ages of 368±3.5 Ma (of granite, 95% confidence level, MSDW=1.23) and 362.9±6.1 Ma (of gneiss, 95% confidence level, MSDW = 2.04) respectively. The two late Devonian ages indicate consistently a tectonic- thermal event experienced in Hainan Island, and are the first discovered record of the Devonian geological process in the district. This event possibly resulted from the deep ther-mal-dynamic process when the Gondwana continent began to break up in the Devonian period.The petrological and geochemical features of the bed parallel granitic intrusion in the Pre-Cambrian Baoban group in Hainan Island attest to the anatexis origin of the granites. U-Pb dating analyses of zircons from the anatectic granite and the biotite two-feldspar gneiss in the Baoban group, using SHRIMP II in the Beijing Ion-probe Center, acquire 206Pb/238U ages of 368±3.5 Ma (of granite, 95% confidence level, MSDW=1.23) and 362.9±6.1 Ma (of gneiss, 95% confidence level, MSDW = 2.04) respectively. The two late Devonian ages indicate consistently a tectonic- thermal event experienced in Hainan Island, and are the first discovered record of the Devonian geological process in the district. This event possibly resulted from the deep ther-mal-dynamic process when the Gondwana continent began to break up in the Devonian period.

关 键 词：HAINAN Island  DEVONIAN period  anatectic granite  ZIRCON SHRIMP U-PB dating. 

分 类 号：P597.3[天文地球—地球化学]