缅甸硬玉岩锆石U－Pb年龄及其对新特提斯洋俯冲带.PDF

1000 － 0569 /2014 /030 (08)－ 2279 － 86 Acta Petrologica Sinica 岩石学报 缅甸硬玉岩锆石 U － Pb 年龄及其对新特提斯洋俯冲带 * 流体活动的制约 祁敏1 向华1 张泽明1 钟增球2 QI Min1 ，XIANG Hua1 ，ZHANG ZeMing1 and ZHONG ZengQiu2 1． ， ， 100037 大陆构造与动力学国家重点实验室 中国地质科学院地质研究所 北京 2． ， 430074 中国地质大学地球科学学院 武汉 1． State Key Laboratory for Continental Tectonics and Dynamics ，Institute of Geology ，Chinese Academy of Geological Sciences，Beijing 100037，China 2． Faculty of Earth Sciences ，China University of Geosciences，Wuhan 430074 ，China 2014 － 02 － 01 收稿，2014 － 05 － 15 改回． Qi M ，Xiang H ，Zhang ZM and Zhong ZQ． 2014． Zircon U － Pb ages of Myanmar jadeitite and constrain on the fluid in :2279 － 2286 subduction zone of Neo － Tethys． Acta Petrologica Sinica ，30 (8) Abstract The Jadeite rocks ，which usually produced by the interaction between subduction － related fluids and ultramafic rocks (peridotite)，are generally occurs in serpentinized ultramafic rocks in oceanic subduction zones． The Myanmar jadeitite is the largest and most important jadeitite deposits in the world ，which occurs in a distinctive tectonic unit of the Tethys subduction zone． This paper presents a combined study of zircon geochronology ，microstructure and trace elements in one Myanmar purple jadeitite． Most of the studied zircon grains occur as irregular crystals and experienced various degrees of recrystallization． Zircon U － Pb ages are positively correlated with Ti content indicating that the zircon with low Ti content are experienced higher degree of recrystallization． Unrecrystallized zircons are identified according CL images ，they are characterized by relatively high Th /U ratios (0． 11 ～ 0． 29 )， relatively hig