华北克拉通东南缘蚌埠隆起带荆山—涂山岩体地质地球化学特征再认识  

Review of Geochemical Characteristics of Jingshan-Tushan Granites in Bengbu Uplift,Southeast Margin of North China Craton

作　　者：康丛轩[1,2] 杨献忠 蔡逸涛[1] 宗雯[3] 黄先觉[4] 孔广林[4] 李朝维[4] KANG Congxuan;YANG Xianzhong;CAI Yitao;ZONG Wen;HUANG Xianjue;KONG Guanglin;LI Chaowei(Nanjing Center of Geological Survey,China Geology Survey,Nanjing,Jiangsu 210016,China;;School of Earth Sciences and Engineering,Hofai University,Nanjiny,Janysu 211100,China;Geoloyical Survey of Jiannsu Province,Nanjing,Jiangsu 210018,China;Geological Team 312,Bureau of Geology and Mineral Resources Exploratioo in Angui Province,Bengbu,Angui 233040,China)

机构地区：[1]中国地质调查局南京地质调查中心,江苏南京210016 [2]河海大学地球科学与工程学院,江苏南京211100 [3]江苏省地质调查研究院,江苏南京210018 [4]安徽省地质矿产勘查局312地质队,安徽蚌埠233040

出　　处：《现代地质》2018年第6期1242-1253,共12页Geoscience

基　　金：安徽省公益性地质调查基金项目(2014-K-5)

摘　　要：对位于华北克拉通东南缘蚌埠隆起带的荆山—涂山岩体进行了野外观察、年代学和地球化学研究,测得弱片麻状二长花岗岩体中U-Pb年龄为(160. 4±1. 3)～(162. 8±1. 8) Ma,为晚侏罗世岩浆活动的产物;岩石地球化学测试结果显示,岩体总体富硅、富碱,具有高钾钙碱、准铝—过铝质特征,LREE相对富集,具明显的正Eu异常,Ce异常不明显或无异常,K、P和Ti有较明显的亏损,Rb、Ba、U、La、Sr、Zr和Sm元素相对富集。成因类型判别图显示其具备I型花岗岩特征;锆石Lu-Hf同位素及全岩Sm-Nd同位素组成暗示其物质起源主要为新太古代陆壳,且岩浆源区主要为华北克拉通下地壳物质;构造环境判别图中,投影点落于火山弧花岗岩区域,暗示岩体形成于扬子克拉通沿郯庐断裂带俯冲于华北克拉通之下的构造背景,与华北克拉通晚侏罗世期间的动力学背景相一致。In this study,we carried out field observation,geochronological and geochemical analyses on the Jingshan-'Tushan granites in the Bengbu uplift,southern margin of the North China craton.Zircon U-Pb dating of the weakly-gneissic monzogranite yielded(160.4±1 3)Ma to(162.8±1 8)Ma,suggesting Late Jurassic magmatism.Lithogeochemical data show that the Jingshan-Tushan granites are overall Si-and alkali-rich,high-K calc-alkaline,metaluminous-peraluminous,relatively LREE-enriched,with strong positive Eu anomalies and subtle Ce anomalies.The granites are also depleted in K,P and Ti,and relatively enriched in Rb,Ba,U,La,Sr,Zr and Sm.Data points of the granites fall into the I-type field in the petrogenetic discrimination diagram,and zircon Lu-Hf and whole-rock Sm-Nd compositions suggest that the magma source may have been mainly derived from the Neoarchean continental crust.In tectonic discrimination diagrams,the data points fall mainly in the volcanic arc granite field.It is suggested that the granites were formed in a post-collision extensional setting,consistent with the geodynamic background of the Late Jurassic North China craton.

关 键 词：华北克拉通 蚌埠隆起带 荆山一涂山岩体 地球化学特征 

分 类 号：P588.1[天文地球—岩石学]