地质通报2012，Vol.31Issue(9)：1496-1509,14.
甘肃天水地区早古生代黄门川花岗闪长岩体LA-ICP-MS锆石U-Pb定年及构造意义
LA-ICP-MS zircon U-Pb dating of Early Paleozoic Huangmenchuan granodiorite in Tianshui area of Gansu Province and its tectonic significance
摘要
Abstract
Located in the northern Qilian orogenic belt of Tianshui region within Gansu Province, the Huangmenchuan granodiorite intruded into basic volcanic rocks of the Upper Ordovician Chenjiahe Group. The petrologic and geochemical characteristics show that this granodiorite was formed by emplacement of crust-mande mixed type of magma. The results of LA-ICP-MS zircon U-Pb data of the granodiorite from Huangmenchuan show that the Huangmenchuan granodiorite was emplaced at 440.5Ma±4.4Ma, belonging to Lower Silurian. The element geochemical characteristics indicate that Huangmenchuan granodiorite belongs to middle -K calalkaline series with features of I-type granite. The granodiorite samples are located in Andeans-type continental margin granite area in the environment discrimination diagram. Based on regional geology, the authors hold that there existed a limited ocean basin in Early Paleozoic, and large quantities of arc-type magmatic rocks were produced by the northward subduction of the ocean crust in eastern Qilian orogenic belt. The study of the continental dynamics of the tectonic framework and the evolution history in the area between Qilian and Qinling orogenic belts is of great significance.关键词
花岗闪长岩/LA-ICP-MS锆石U-Pb测年/大陆边缘弧/北祁连造山带/天水地区Key words
granodiorite/LA-ICP-MS zircon U-Pb dating/continental marginal arc/northern Qilian orogenic belt/Tianshui area分类
天文与地球科学引用本文复制引用
魏方辉,陈有炘,裴先治,李瑞保,李佐臣,裴磊,高景民,王银川,刘成军,吴树宽..甘肃天水地区早古生代黄门川花岗闪长岩体LA-ICP-MS锆石U-Pb定年及构造意义[J].地质通报,2012,31(9):1496-1509,14.基金项目
国家自然科学基金项目《西秦岭北缘变形构造解析及其祁连-秦岭构造交接关系研究》(批准号:40972136)、中央高校基本科研业务费专项资金项目《中央造山系(中西段)关键构造部位复合造山作用研究》(编号:CHD2011TD020)和中国地质调查局地质调查项目《天水市幅1:25万区域地质调查(修测)》(编号:200013000154) （批准号:40972136）
