东昆仑造山带东段香日德地区早三叠世侵入岩岩石时代及形成机制探讨

Study on Rock Age and Formation Mechanism of Intrusive Rocks in Eary Triassic in Xiangride Area in East Kunlun Orogenic

近年来，随着高精度锆石U—Pb测年技术的应用，众多学者认为东昆仑造山带晚华力西期一印支期岩浆岩异常发育，为主要的活动时期，并且将东昆仑造山带东段的岩浆活动界定在260～220Ma时间段内。该文对东昆仑造山带地区东段香日德地区出露的花岗岩进行详细的LA—ICP—MS锆石U—Pb年代学研究，获得花岗闪长岩锆石LA—ICP—MSU—Pb表面年龄加权平均值为（248．43±0．64）Ma，应该为岩体结晶年龄，属于早印支期。同时东昆仑东段的岩浆活动随着时间的推移，还表现出由东向西（沟里→香日德→香日德）和由南向北（东昆南→东昆北）扩散的趋势。

In recent years, accompanying with the application of high precision U--Pb zircon dating tech- niques, many scholars believe that late Variscan--Indosinian magmatic rocks developed abnormally in East Kunlun orogenic belt. It is main activity period, and magmatic activities in East Kunlun orogenic belt is de- fined in 260-220Ma. Granites exposed in Xiangride area in East Kunlun orogenic belt have been stuided in detail by using LA--ICP--MS and U--Pb zircon geochronology. It is obtained that zircon LA--ICP--MS --U--Pb surface age weighted average of granodiorite is （248.43± 0.64） Ma. It should be the crystalliza- tion age of rock mass, and belongs to early indosinian. As the time goes, magmatic activities in the eastern section of East Kunlun also showed the diffusion trend from east to west （Gouli →Xiangride→Xiangride） and from south to north （southern East Kunlun→northern East Kunlun） .