北祁连香子沟榴辉岩相变沉积岩的锆石U-Pb年代学,Hf同位素特征及其地质意义

CORC > 北京大学 > 地球与空间科学学院

	北祁连香子沟榴辉岩相变沉积岩的锆石U-Pb年代学,Hf同位素特征及其地质意义; Zircon U-Pb geochronology and Hf-isotope compositions of the eclogitic metasedimentary rocks in Xiangzigou, North Qilian Mountains and their geological implications
	喻星星 ; 张建新
刊名	岩石学报
	2016
关键词	榴辉岩相变沉积岩锆石 U-Pb定年 Hf同位素北祁连 Eclogitic metasedimentary rock Zircon U-Pb dating Hf isotope North Qilian HP/LT METAMORPHIC TERRANE CONVERGENT PLATE MARGINS SUBDUCTION-CHANNEL MODEL NW CHINA EVIDENCE SEDIMENT SUBDUCTION MELANGE FORMATION PRISM ACCRETION WESTERN CHINA GEODYNAMIC IMPLICATIONS TECTONIC IMPLICATIONS
英文摘要	榴辉岩相变沉积岩普遍分布在北祁连HP/LT变质带中,在HP/LT变质带的西段香子沟地区,变质沉积岩的矿物组合为石英+多硅白云母+石榴子石+绿帘石±蓝闪石±绿辉石(+金红石+锆石).利用石榴子石-绿辉石-多硅白云母地质温压计获得变沉积岩的峰期变质温度为448～467℃,压力为2.0～ 2.2GPa.锆石SHRIMP和LA-ICPMS U-Pb测试结果显示,碎屑锆石核的年龄分布在532～ 2700Ma之间,大部分集中在中元古代和晚古元古代之间,显示原岩的碎屑物质主要来源于中-古元古代岩石.2个样品的变质锆石边获得的206Pb/238U加权平均年龄分别为495±7Ma(MSWD=0.63)和496±7Ma(MSWD=5.6),代表了榴辉岩相变质年龄.结合前人研究成果和锆石Hf同位素特征,表明榴辉岩相变沉积岩的原岩形成于以陆缘碎屑为主的活动大陆边缘或弧前环境,在早古生代洋壳俯冲过程中,通过俯冲剥蚀作用被卷入到俯冲带深部,与所包裹的基性岩(榴辉岩的原岩)一起发生榴辉岩相变质作用,并快速折返至浅部.; The eclogitic metasedimentary rocks occur pervasively in the high pressure/low temperature (HP/LT) metamorphic belt in the North Qilian Mountain (NQL). In Xiangzigou area, western part of the NQL HP/LT metamorphic belt, metasedimentary rocks mainly consist of Grt + Phe + Qtz + Ep +/- Gln +/- Omp. Grt-Omp geothermometer and Grt-Omp-phe geobarometer yield a metamorphic condition of 448 similar to 467 degrees C and 2.0 similar to 2.2GPa for the peak assemblage. SHRIMP and LA-MC-ICPMS U-Pb dating data show that detrital zircons from metasedimentary rocks have ages ranging from 532Ma to 2700Ma with dominant Mesoproterozoic to Late Paleoproterozoic ages. The metamorphic rims from two samples yield the weighted average ages of 495 +/- 7Ma (MSWD = 0.63) and 496 +/- 7Ma (MSWD = 5.6), respectively, representing eclogitic facies metamorphism age. Combining with the zircon Hf isotope and previous studies, the protoliths of these metasedimentary rocks possibly formed in terrigenous-dominated continental margin or fore-arc setting, and were transported into deep subduction zone by subduction erosion during Early Paleozoic, and underwent coeval eclogite facies metamorphism together with the enclosed eclogites prior to the rapid exhumation.; SCI(E); 中文核心期刊要目总览(PKU); 中国科技核心期刊(ISTIC); star2yu@yeah.net; zjx66@yeah.net; 5; 1437-1451; 32
语种	中文
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/492341]
专题	地球与空间科学学院
推荐引用方式 GB/T 7714	喻星星,张建新. 北祁连香子沟榴辉岩相变沉积岩的锆石U-Pb年代学,Hf同位素特征及其地质意义, Zircon U-Pb geochronology and Hf-isotope compositions of the eclogitic metasedimentary rocks in Xiangzigou, North Qilian Mountains and their geological implications[J]. 岩石学报,2016.
APA	喻星星,&张建新.(2016).北祁连香子沟榴辉岩相变沉积岩的锆石U-Pb年代学,Hf同位素特征及其地质意义.岩石学报.
MLA	喻星星,et al."北祁连香子沟榴辉岩相变沉积岩的锆石U-Pb年代学,Hf同位素特征及其地质意义".岩石学报 (2016).