Zircon U-Pb dating for metavolcanites in the Laochanghe Formation of the;Dahongshan Group in southwestern Yangtze Block, and its geological;significance

	Zircon U-Pb dating for metavolcanites in the Laochanghe Formation of the;Dahongshan Group in southwestern Yangtze Block, and its geological;significance
	Yang Hong; Liu FuLai; Du Lilin; Liu PingHua; Wang Fang
刊名	ACTA PETROLOGICA SINICA
	2012
卷号	28 期号:9 页码:2994-3014
关键词	LA-ICP-MS Zircon U-Pb dating Laochanghe Formation Dahongshan Group Yangtze Block
ISSN号	022HC
英文摘要	Dahongshan Group is one of the oldest stratigraphic units in western Yangtze Block, which experienced metamorphism of greenschist-lower amphibolite facies. Depositional ages (similar to 1.68Ga, the Late Paleoproterozoic) of the Manganghe and Hongshan formations in the middle of this group have already been achieved, while that of the Laochanghe Formation at the bottom of the group has not been reported until now. Compared to its depositional ages, no accurate statistics have been reached for the metamorphic ages. This study works on the metavolcanites as thin layers in the thick metasedimentary rocks of the Laochanghe Formation. Petrography, in situ LA-ICP-MS zircon U-Pb dating and the related trace element and BEE analyses provided insights into the protolith and metamorphic ages of the rocks. Results are as follows. (1) Magmatic zircon domains of the meta-intermediate-acid and metabasic rocks in the Laochanghe Formation have the weighted average Pb-207/Pb-206 ages of 1711 +/- 4Ma and 1686 +/- 4Ma respectively, and zircon ages constrain the timing of the Laochanghe to the range from 1711Ma to 1686Ma; (2) Metamorphic zircon domains in a metabasic rock (garnet amphibolite) has Pb-206/U-238 zircon age of 849 +/- 12Ma. The results show that the starting age of the Dahongshan Group is advanced to 1711 +/- 4Ma which confirms again the existence of the old crystalline basement in western Yangtze Block, and that there was a metamorphic event around similar to 850Ma in the Neoproterozoic which must be a regional metamorphism related to the Neoproterozoic magmatism.
学科主题	变质岩岩石学
WOS关键词	SOUTH CHINA ; SICHUAN PROVINCE ; WESTERN MARGIN ; RODINIA ; AGES ; GEOCHRONOLOGY ; GEOCHEMISTRY ; PETROGENESIS ; METAMORPHISM ; MAGMATISM
WOS研究方向	Geology
语种	中文
WOS记录号	WOS:000309947500025
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/39646]
专题	中国地质科学院地质研究所
作者单位	Chinese Acad Geol Sci, Inst Geol, Beijing 100037, Peoples R China.
推荐引用方式 GB/T 7714	Yang Hong,Liu FuLai,Du Lilin,et al. Zircon U-Pb dating for metavolcanites in the Laochanghe Formation of the;Dahongshan Group in southwestern Yangtze Block, and its geological;significance[J]. ACTA PETROLOGICA SINICA,2012,28(9):2994-3014.
APA	Yang Hong,Liu FuLai,Du Lilin,Liu PingHua,&Wang Fang.(2012).Zircon U-Pb dating for metavolcanites in the Laochanghe Formation of the;Dahongshan Group in southwestern Yangtze Block, and its geological;significance.ACTA PETROLOGICA SINICA,28(9),2994-3014.
MLA	Yang Hong,et al."Zircon U-Pb dating for metavolcanites in the Laochanghe Formation of the;Dahongshan Group in southwestern Yangtze Block, and its geological;significance".ACTA PETROLOGICA SINICA 28.9(2012):2994-3014.