^(40)Ar/^(39)Ar dating for Cenozoic kamafugite from western Qinling in Gansu Province  

作　　者：YU Xuehui ZHAO Zhidan ZHOU Su MO Xuanxue ZHU Deqing WANG Yonglei 

机构地区：[1]State Key Laboratory of Geological Processes and Mineral Resources, Key Laboratory of Lithosphere Technology of Ministry of Education, China University of Geosciences, Beijing 100083, China

出　　处：《Chinese Science Bulletin》2006年第13期1621-1627,共7页

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.402340520,4997301 and 40172025);the Major State Basic Research Development Program from the Ministry of Science and Technology(Grant No.2002CB412600);the Key Project of QTP from MLR(Grant No.200101020404).

摘　　要：40Ar/39Ar ages were determined for 6 phlogopite samples from a kamafugite pipe occurring in western Qinling, yielding a time span of 22 to 23 Ma for kamafugite eruption. Together with known geochronological data for the Qinghai-Tibet Plateau (QTP) and its peripheral regions, it is concluded that these Cenozoic potassic-ultrapotassic volcanic rocks are products of post-collisional volcanism. The age of the Cenozoic volcanic rocks in western Qinling partly overlaps that of potassic volcanics from the Gandise belt, reflecting the northward migration of the post-collisional volcanism in QTP. The age data not only confirm the temporal and spatial migration of post-collisional volcanism in QTP, but also provide geochronological constraints on the geodynamic set- ting at depth and the regimes of the tectonic evolution since Neogene in western Qinling regions.Abstract ^40Ar/^39Ar ages were determined for 6 phlogopite samples from a kamafugite pipe occurring in western Qinling, yielding a time span of 22 to 23 Ma for kamafugite eruption, Together with known geochronological data for the Qinghai-Tibet Plateau （QTP） and its peripheral regions, it is concluded that these Cenozoic petassic-ultrapotassic volcanic rocks are products of pest-cellisienal volcanism, The age of the Cenozoic volcanic rocks in western Qinling partly overlaps that of petassic velcanics from the Gandise belt, reflecting the northward migration of the pest-cellisienal volcanism in QTP, The age data net only confirm the temporal and spatial migration of pest-cellisienal volcanism in QTP, but also provide geochronological constraints on the geedynamic setting at depth and the regimes of the tectonic evolution since Neogene in western Qinling regions.

关 键 词：同位素年代测定 钾霞橄黄长岩 西秦岭 新生代 甘肃 

分 类 号：P585[天文地球—岩石学]