特提斯喜马拉雅泛非-早古生代造山事件:康马片麻状二长花岗岩的年代学证据

Pan-African and Early Paleozoic Geological Orogenic Events in the Tethyan Himalaya:From Chronological Evidence of Gneissic Monzonitic Granite,Kangma,Tibet

对康马片麻状二长花岗岩进行了高精度锆石LA-ICP-MSU-Ph定年，获得了多组锆石U-Pb年龄：1509.3～953.7，528．8～485．0，439．2～385．8Ma。1509．3～953．7Ma年龄数据证实了康马地区乃至特提斯喜马拉雅地体变质基底岩石为中新元古代产物；康马片麻状二长花岗岩的冷却年龄为528．8Ma，是泛非事件在特提斯-喜马拉雅康马-带的重要地质记录；485.0Ma是泛非事件延续至早古生代的重要年龄记录，证实了康马二长花岗岩同时卷入泛非事件和早古生代事件中；439.2～385.8M。年龄数据显示康马片麻状二长花岗在485M。（泛非-早古生代事件）之后，仍然经历了多期次的岩浆构造热事件。从年代学方面显示康马片麻状二长花岗岩是多期岩浆构造热事件综合作用的产物，本次获得的年龄数据对复原泛非期-古生代地质演化具有重要地质意义。

The high precision zircon LA-ICP-MS U-Pb dating of gneissic monzonitic granite in Kangma indicates that more groups of zircon U-Pb are aged respectively 1 509.3-953.7 Ma,528.8-485.0 Ma,and 439.2-385.8 Ma. The age data（1 509.3-953.7 Ma） confirmed the metamorphic rocks of the basement in Kangma region to Tethys Himalaya rockhody are Mesoproterozoic and Neoproterozoic products. The cooling age of Kangma gneissic monzonitic granite, 528.8 Ma, is an important geological record for the Pan- African events in the area of the Tethys-Himalayan Kangma. The age data,485.0 Ma, an important age record of Pan-African events continuing to Early Paleozoic confirms that the monzonitic granite was involved in the Pan-African and Early Paleozoic events. The age data（439.2-385.8 Ma） show that the Kangma gneissic monzonitic granite should have undergone many times of magma tectonic thermal events after 485 Ma. From the aspects of chronology the Kangma gneissic monzonitic granite was multiphase magmatic tectonic thermal event combination product. The age data covery of Pan-African Paleozoic geological evolution. obtained is of geological significance for the the recovery of Pan-African Paleozoic geological evolution.