摘要
针对浙中地区后山店花岗斑岩体进行高精度LA-ICP-MS锆石U-Pb测年和锆石Lu-Hf同位素的测定。测年结果显示其加权平均年龄值为148.5 Ma±1.2 Ma(MSWD=1.4),说明浙中地区有晚侏罗世侵入岩的存在,属于燕山早期晚阶段岩浆活动的产物,其成岩时代可能代表了古太平洋构造域下的板内岩浆活动和陆缘弧间的过渡阶段。锆石的εHf(t)值为-10.3^-3.5,均为负值,二阶段模式年龄tHf2(Ma)变化范围主要集中于1 400 Ma^1 829 Ma之间,反映其物质来源可能为中元古代下地壳基底物质,并在成岩过程中有幔源组分的参与。
Late Mesozoic intrusive rocks distributed in whole Zhejiang Province are located in the southeastern margin of the Eurasian plate,and mostly concentrated in the Cretaceous period,as products of Late Yanshanian magmatic activity,and rarely reported for the record of the Early Yanshanian Period.LA-ICP-MS U-Pb dating and Lu-Hf isotopic analysis of zircons are carried out from representative rock samples of Houshandian granite porphyry pluton in central of Zhejiang Province.Weighted average ages of（148.5±1.2）Ma（MSWD=1.4）is interpreted as the formation time of the granite porphyry,indicating the existence of Late Jurassic intrusive rocks in central Zhejiang,which are formed by late stage of Early Yanshanian magmatic activity.The time of rock formation may represent a transitional phase from intraplate magmatism to continental margin arc by Paleo-Pacific tectonic domain.ZirconεHf（t）values of the granite porphyry are all negative（-10.3to-3.5）,and two-stage Hf model ages（tHf2）range from 1 400 Ma to 1 829 Ma,suggesting that the granite porphyry is originated from remelting of the Mesoproterozoic lowercrust basement materials,and there are mantle-derived components participated during diagenesis.
出处
《矿物岩石》
CAS
CSCD
北大核心
2015年第1期49-56,共8页
Mineralogy and Petrology
基金
中国地质调查局地质调查项目(1212011121068)
国家自然科学基金面上项目(41271344)
石家庄经济学院博士科研启动基金联合资助
