北淮阳浅变质岩带卢镇关群变质压力及其对大别造山带演化的指示  

Metamorphic Pressure of the Luzhenguan Group in the North Huaiyang Low-grade Metamorphic Belt and Its Indication for Evolution of the Dabie Mountains

作　　者：王勇生[1] 盛勇[1] 向必伟[2] 张承云[1] 

机构地区：[1]合肥工业大学资源与环境工程学院,合肥230009 [2]中国地质大学(武汉)地球科学学院,武汉430074

出　　处：《地质论评》2012年第5期865-872,共8页Geological Review

基　　金：国家自然科学基金资助项目(批准号40602025);安徽省杰出青年基金项目(编号1108085J12);中国地质调查局科技项目(编号1212011121114)的成果

摘　　要：卢镇关群是北淮阳浅变质岩带的重要组成部分,其俯冲历史对于证明超高压岩石经历了深俯冲及获得完整的大别造山带演化历史具有重要意义。本次工作在霍山牛角冲、与儿街卢镇关群岩石中采集了含石榴子石的黑云二长片麻岩和石榴黑云片麻岩进行电子探针分析,并通过石榴子石—黑云母—斜长石—石英压力计计算获得了卢镇关群的变质压力变化于1.89～1.99 GPa,其平均值为1.94 GPa。根据造山带内中—上地壳岩石的平均密度,获得了卢镇关群曾俯冲于地下64.7 km的深度。这表明位于大别造山带最北缘的北淮阳带曾俯冲于较大深度,支持前人关于华南、华北板块缝合线位于北淮阳带以北的结论。The Luzhenguan Group is an important part of the North Huaiyang low-grade metamorphic belt （NH） , whose evolution process is critical for offering evidences for deep-subduction of the uhra-pressure rocks and getting integrated history of the Dabie Mountains. In this work, some biotite two feldspar gneisses with garnet and garnet-biotite gneisses were collected in Niujiaochong and Yu＇ erjie, Huoshan County, for electronic analysis. Using the garnet-biotite-plagioclase-quartz geobarometry, metamorphic pressure between 1.89 - 1.99 GPa and the average 1.94 GPa was gained. Based on average density of the rocks located in upper and middle crust of the Dabie Mountains, a conclusion is drawn that the Luzhenguan Group once subducted into 64.7 km in depth. This conclusion suggests that the North Huaiyang belt experienced deeper subduction and supports that the suture zone between the North China block and the South China locates in north of the North Huaiyang belt.

关 键 词：大别造山带 卢镇关群 变质压力 造山带演化 

分 类 号：P542.2[天文地球—构造地质学]