The latest Yanshanian magmatic and metallogenic events in the middle-lower Yangtze River belt: Evidence from the Ningzhen region  

作　　者：SUN Yang MA ChangQian LIU YuanYuan 

机构地区：[1]Faculty of Earth Sciences, China University of Geosciences [2]Faculty of Earth Sciences, Yangtze University [3]State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences

出　　处：《Chinese Science Bulletin》2013年第34期4308-4318,165-171,共11页

基　　金：supported by the National Key Basic Research Program of China(2012CB416800);the Key International Science and Technology Cooperation project(2007DFA21230)

摘　　要：The Ningzhen region in Jiangsu Province represents the easternmost magmatic region in the middle-lower Yangtze River belt.The formation of the polymetallic deposits has close genetic relationships with Early Cretaceous intermediate-acid intrusions.In this study,LA-ICP-MS zircon geochronology of two Mesozoic intermediate-acid intrusive rocks(including the Shima porphyritic granodiorite and Gaozi quartz diorite porphyry)in the Ningzhen region were systematically investigated.These new geochronological data demonstrate that the intermediate-acid magmatism in the Ningzhen region dates to approximately between 109 and101 Ma.We present new40Ar-39Ar phlogopite ages for the Cishantou skarn iron deposits that constrain the timing of the mineralisation in the Ningzhen region.The phlogopite in the Cishantou skarn deposits yielded a40Ar-39Ar plateau age of 104±1 Ma.This result coincides with the ages of the Anjishan and Tongshan Cu(Mo)deposits in the Ningzhen region.Our high-precision geochronological data together with recent high-precision geochronological studies(such as zircon LA-ICP-MS U-Pb,zircon SHRIMP U-Pb,molybdenite Re-Os and single-mineral40Ar-39Ar dates)reveal that there were four periods(152-135 Ma,135-127 Ma,127-121 Ma,109-101 Ma)of magmatism and ore formation in the middle-lower Yangtze River metallogenic belt.The Mesozoic intermediate-acid magmatism and mineralisation in the Ningzhen region belong to the latest episode in the middle-lower Yangtze River metallogenic belt.The Ningzhen region in Jiangsu Province represents the easternmost magmatic region in the middle-lower Yangtze River belt. The formation of the polymetallic deposits has close genetic relationships with Early Cretaceous intermediate-acid intrusions. In this study, LA-ICP-MS zircon geochronology of two Mesozoic intermediate-acid intrusive rocks （including the Shima porphyritic granodiorite and Gaozi quartz diorite porphyry） in the Ningzhen region were systematically investigated. These new geochrono- logical data demonstrate that the intermediate-acid magmatism in the Ningzhen region dates to approximately between 109 and 101 Ma. We present new 4~Ar-39Ar phlogopite ages for the Cishantou skarn iron deposits that constrain the timing of the mineral isation in the Ningzhen region. The phlogopite in the Cishantou skarn deposits yielded a 4Ar-39Ar plateau age of 104±1 Ma. This result coincides with the ages of the Anjishan and Tongshan Cu （Mo） deposits in the Ningzhen region. Our high-precision geo chronological data together with recent high-precision geochronological studies （such as zircon LA-ICP-MS U-Pb, zircon SHRIMP U-Pb, molybdenite Re-Os and single-mineral 4Ar-39Ar dates） reveal that there were four periods （152-- 135 Ma, 135-- 127 Ma, 127--121 Ma, 109--101 Ma） of magmatism and ore formation in the middle-lower Yangtze River metallogenic belt. The Mesozoic intermediate-acid magmatism and mineralisation in the Ningzhen region belong to the latest episode in the mid dle-lower Yangtze River metallogenic belt.

关 键 词：长江中下游 宁镇地区 岩浆活动 成矿带 LA-ICP-MS 中酸性侵入岩 U-Pb年龄 燕山期 

分 类 号：P611[天文地球—矿床学]