摘要
对大别山高压-超高压片麻岩的锆石进行了激光拉曼探针、阴极发光(CL)、U-Pb年龄和U、Th等微量元素的测定分析。研究结果表明:锆石拉曼光谱1008cm^(-1)峰的半高宽普遍小于20cm^(-1),指示锆石结晶程度较好到中等程度的蜕晶化;早期继承锆石在三叠纪高压-超高压变质作用中经历了退火和重结晶作用,所受的放射性通量是从200Ma的早侏罗纪开始积累的,表明高压-超高压岩石在这一时间已出露地表;北大别白垩纪岩浆热事件对高压-超高压岩石的影响很小;大多数锆石数据都落在天然锆石的放射性破坏趋势(RDT)中,表明锆石在高压、超高压过程中基本发生了完全的重结晶。
The zircons from gneisses in high and ultrahigh-pressure (HP-UHP) metamorphic zones of the Dabie Mountains have been investigated by using Laser Raman microprobe analysis, cathodoluminescence (CL) images, U-Pb ages and trace elements measured by LA-ICP-MS. Most of the FWHMs (full widths at half-maxmum) of 1008cm(-1) band of zircons are less than 20cm(-1) suggesting that zircons are well crystallized to moderately damaged. The early inherited zircons from gneisses bad undergone significant annealing and recrystallization during the HP-UHP metamorphic event. The a-doses that zircons suffered are probably accumulated from about 200Ma, indicating that HP-UHP metamorphic rocks have been exhumed to the Surface of the earth at this time. The magmatic events of Cretaceous age in North Dabie may exert little effect on the HP-UHP rocks, which most of FWHMs and frequencies of zircons in Dabie Moutains fall into the natural radiation damage trend (RDT), indicating completely recrystalization of zircons during the HP-UHP metamorphic event.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2009年第9期2157-2164,共8页
Acta Petrologica Sinica
基金
国家自然科学基金(40672054)
创新研究群体科学基金(40721062)
西北大学大陆动力学国家重点开放实验室开放课题基 金(07LCD15)的资助
