安徽月山岩体的锆石SHRIMP U-Pb定年及其意义  

SHRIMP U-Pb zircon dating of Yueshan intrusion in the Yueshan ore field,Anhui,and its significance

作　　者：张乐骏[1] 周涛发[1] 范裕[1] 袁峰[1] 

机构地区：[1]合肥工业大学资源与环境工程学院,合肥230009

出　　处：《岩石学报》2008年第8期1725-1732,共8页Acta Petrologica Sinica

基　　金：国家重点基础研究发展规划973项目(2007CB411405);国家自然科学基金项目(40672062;40830426;40803015);高等学校博士学科点科研基金项目(20050359013);安徽省优秀青年科技基金资助项目(08040106907)资助

摘　　要：月山岩体是长江中下游成矿带中安庆—贵池矿集区内月山矿田中最重要的中酸性侵入岩体。本文对月山岩体主要岩石——闪长岩进行了锆石 SHRIMP U-Pb 定年,得到年龄值为138.7±0.5Ma,表明岩体形成于早白垩世。该结果与铜陵等地的高钾钙碱性中酸性侵入岩的形成时代类似,但早于月山矿田内的花岗质岩体和庐枞盆地、宁芜盆地中的岩浆岩。在综合区内已有的岩石学、地球化学和成矿年代学资料的基础上,认为月山矿田内的铜金铁成矿作用与月山岩体的形成有着密切的成因联系,二者在时间上是一个连续的过程,皆发生于燕山期,成岩成矿作用过程发生于区域挤压—拉张过渡的构造背景。The Yueshan intrusion is the most important intermediate-acid intrusive body in the Yueshan ore field, which is in the Anqing-Guichi ore deposit concentrated area in the mineralization belt of the Middle and Lower Reaches of the Yangtze River area. In this paper we present a SHRIMP U-Pb zircon age of 138. 7 ± 0. 5Ma for diorite from the Yueshan intrusion, which suggests an Early Cretaceous age for the formation of this intrusion. The result is coincident with the age of high-K calc-alkaline intermediate-acid intrusive rocks in the Tongling ore deposit concentrated area, but earlier than the formation age of granitic intrusion in the Yueshan ore field and the shoshonite series rocks in the Luzong and Ningwu volcanic basins. On the base of an integrated study of available petrological, geochemical and isotopic dating of magmtic rocks and deposits in the Yueshan ore field, we concluded that the magmatism and mineralization of the Yueshan ore field is a continuous process in the Yanshanian era, which took place in a transitional tectonic environment from compression to extension in Mesozoic.

关 键 词：月山岩体 锆石SHRIMP U—Pb定年 长江中下游成矿带 

分 类 号：P597.3[天文地球—地球化学]