【摘 要】
:
TTG gneiss is a common rock to outcrop in the northern part of the Dabie orogen, a few of which are closely associated with eclogites that experienced the Trias
【机 构】
:
Earth Material Cycling Laboratory
论文部分内容阅读
TTG gneiss is a common rock to outcrop in the northern part of the Dabie orogen, a few of which are closely associated with eclogites that experienced the Triassic ultrahigh pressure metamorphism. Although they were thermally metamorphosed by a large-scale magma activity in this region at the Early Cretaceous, it is unclear whether or not they are also affected by the Triassic metamorphism during continental subduction and exhumation. In order to resolve this issue, SHRIMP zircon U-Pb dating was carried out for the host gneiss of eclogites in North Dabie. The results show that cores from the gneiss have an age of 746±31 Ma, consistent with the protolith ages of granitic gneisses in the Dabie orogen. Zircon overgrowing with different U and Th concentrations give concordant ages of 212±21 and 120±11 Ma, respectively. Th/U ratios of overgrown zircons are both lower than 0.1, suggesting a metamorphic genesis. The present results suggest that the gneiss in North Dabie has the similar protolith ages of Neoproterozoic to those granitic gneisses elsewhere in the Dabie orogen, and experienced not only the Triassic metamorphism but also the thermal metamorphism due to the Early Cretaceous magmatism. This provides an important insight into the geodynamic evolution of gneissic rocks in the Dabie orogen.
其他文献
和谐社会应当是法治社会。和谐社会语义的提出为中国法治主义提供了新的方向。我们分析了和谐社会下的法律表征,强调和谐社会的构建应当充分考虑到中国社会的传统因素的影响
磷灰石裂变径迹(AFT)分析表明松辽盆地晚期构造活动在空间上具有分区性,在时间上具有幕式性.空间上的分区性表现在晚期构造活动始于盆地东部,并逐渐向西部迁移.盆地东部裂变径迹年龄大,表明进入抬升剥蚀作用的时间早,而西部裂变径迹年龄小,表明进入抬升剥蚀作用的时间晚.盆地的抬升剥蚀量与主要构造单元关系密切,但是东部的抬升剥蚀量明显大于中央隆起带和西部斜坡带.时间的幕式性表现在盆地的热演化历史经历了两幕快
研究分析了当前地铁隧道风亭组集水井独立设置排水系统设备设施,存在排水设备设施繁杂、管理维护工作量大以及建设投资费用高的问题;本着节能降耗优化设计的理念,提出了在集
Global abrupt climate changes have been documented by various climate records, including ice cores,ocean sediment cores, lake sediment cores, cave deposits,loes
Double radionuclide tracers of 137Cs and 210Pb were used to investigate sediment sources in the Wujia Gully,a small catchment in the Hilly Sichuam Basin in 2002
Ultra-Violet Laser Ablation Microprobe (UVLAMP) extraction technique enables the direct investigation of Ar-Ar age profile in crystals, and yields more informat
The high pressure pelitic granulite with peak assemblage of garnet + kyanite + ternary feldspar + muscovite + rutile was discovered in Qixia area in the Precamb
Whole-rock and mineral separate Ar-Ar dating was carried out for the Linzizong volcanic rocks at Linzhou Basin in Tibet to constrain the time span of volcanism
The Xinzhai Period (3550-3400 aBP) belongs to Late Neolithic Culture, which bridges the Longshan Culture and the Xia Culture in the Central Plains of China. By
The mesostructure at the cross section of the Fe-based nanocrystalline (Fe73.5Cu1Nb3Si13.5B9) ribbon was observed with atomic force microscopy (AFM). An apparen