Geochronology of pegmatite in the Baoban complex in the western Hainan and its geological significance
In order to clarify the formation age of pegmatite in the Baoban complex in the western Hainan,to reveal the genetic relationship between the pegmatite and the Baoban complex,as well as to trace the tectonic evolution of Hainan Island,in this study,based on the study of geological characteristics of the pegmatite,the LA-ICP-MS U-Pb geochronological study of monazite and xenotime from the pegmatite has been carried out.The results show that the 206Pb/238U weighted mean age of xenotime from the pegmatite(HPGZ-11)intruded into the Gezhencun Formation was(351.3±1.8)Ma.The 208Pb/232Th weighted mean age of monazite form the pegmatite(HPGZ-21)intruded into the Proterozoic gneissic granite was(432.6±1.3)Ma.Based on the previous research data and the results of this study,it is believed that the HPGZ-21 and HPGZ-11 pegmatites were formed in the Silurian and Carboniferous periods,respectively,rather than the previously believed Mesoproterozoic,and their formation may be respectively related to Caledonian movement and the continuous rifting event from the Middle-Late Devonian to Carboniferous in Hainan Island.
monazitexenotimeU-Pb geochronologypegmatiteBaoban complexHainan Island
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NSTL
万方数据
