云开地区早古生代竹雅-石板辉长岩锆石U-Pb定年与Lu-Hf同位素特征
发布时间：2018-09-14 16:14
【摘要】：华夏地块西段的云开地区出露少量早古生代基性侵入岩,多以小岩株状侵入前寒武纪变质地层或与同期片麻状花岗岩共生,岩石类型主要为辉长岩和苏长辉长岩。LA-ICP-MS锆石U-Pb测年显示,信宜竹雅和高州石板辉长岩结晶年龄约为445Ma。辉长岩岩石地球化学以富MgO、CaO,相对贫TiO_2为特征,具有极低的稀土元素总量(∑REE=20.8×10~(-6)~26.6×10~(-6)),轻稀土元素略微富集,亏损Nb、Zr、Ti、P等高场强元素。锆石ε_(Hf)(t)均为弱的负值,Hf同位素一阶段模式年龄介于1.1~1.4Ga之间,显示富集地幔源区特征。构造环境分析表明,辉长岩与火山弧玄武岩相似。综合前人研究认为,华夏地块早古生代存在一系列具典型弧火山岩特征的基性岩类,这对早古生代构造运动的认识具有重要的限定作用。
[Abstract]:A small amount of early Paleozoic basic intrusive rocks appeared in Yunkai area of the western part of the Huaxia massif, and most of them intruded into the Precambrian metamorphic strata or symbiotic with the corresponding schneismatic granites. The main rock types are gabbro and sulcanite. LA-ICP-MS zircon U-Pb dating shows that the crystallization age of Xinyi Zhuya and Gaozhou slate gabbro is about 445 Ma. The rock geochemistry of gabbro is characterized by rich MgO,CaO, and relatively poor TiO_2, with extremely low REE contents (鈭，
本文编号：2243214
[Abstract]:A small amount of early Paleozoic basic intrusive rocks appeared in Yunkai area of the western part of the Huaxia massif, and most of them intruded into the Precambrian metamorphic strata or symbiotic with the corresponding schneismatic granites. The main rock types are gabbro and sulcanite. LA-ICP-MS zircon U-Pb dating shows that the crystallization age of Xinyi Zhuya and Gaozhou slate gabbro is about 445 Ma. The rock geochemistry of gabbro is characterized by rich MgO,CaO, and relatively poor TiO_2, with extremely low REE contents (鈭，
本文编号：2243214
本文链接：https://www.wllwen.com/kejilunwen/diqiudizhi/2243214.html
