宁夏卫宁北山金场子闪长玢岩岩脉地质特征及SHRIMP锆石U-Pb年龄  

Geological characteristics and zircon SHRIMP U-Pb data of Jinchangzi dioritic porphyrite dykes in Zhongwei City,Ningxia

作　　者：刘勇[1] 李廷栋[2] 王彦斌[1] 肖庆辉[3] 耿树方[1] 王涛[1] 

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]国土资源部咨询研究中心,北京100035 [3]中国地质调查局发展研究中心,北京100037

出　　处：《中国地质》2010年第6期1575-1583,共9页Geology in China

基　　金：全国重要矿产成矿地质背景研究项目(1212010733802);中国东部中生代大陆岩石圈剧变过程;动力学机制与矿产资源的响应项目(1212010711814);中国地质调查局地质大调查项目(1212010611803)资助

摘　　要：卫宁北山地区的金场子闪长玢岩岩脉分布较广,在空间上与矿化带密切共生,很可能与区域隐伏的中酸性岩体是同源、同期形成的,而隐伏的中酸性岩体可能就是研究区多金属成矿的矿源和中心。因而研究其形成时代对研究区找矿具有重要意义。用SHRIMP锆石U-Pb法获得的闪长玢岩年龄为(147.2±2.3)Ma(MSWD=1.6),形成时代为晚侏罗世,属燕山期。燕山期中酸性岩浆活动的确认为深入理解中国西部中生代岩石圈的演化、构造背景及其对卫宁北山花岗岩活动与成矿作用的制约效应等提供了重要依据。Jinchangzi dioritic porphyrite dykes widely distributed in the study area are spatially closely associated with the mineralized zone.These dykes were probably of the same source with the regional concealed acid intermediate-acid rocks and formed simultaneously with these rocks.These concealed acid rocks in the study area might have been the source and center of polymetallic mineralization,and hence a study of their formation epoch is of great significance for the ore-prospecting work in the study area.SHRIMP zircon U-Pb dating of the diorite yielded an age of（147.2±2.3）Ma（MSWD=1.6）,indicating Late Jurassic of Yanshanian period.The confirmation of Yanshanian acid activity has provided an important basis for understanding the evolution of the Mesozoic lithosphere in western China,its tectonic setting and its constraints for Weiningbeishan granite and mineralization.

关 键 词：金场子 闪长玢岩岩脉 SHRIMP锆石U-PB定年 卫宁北山 

分 类 号：P597.3[天文地球—地球化学]