Early Permian magmatic events in the Alxa metamorphic basement: Evidence;from geochronology

	Early Permian magmatic events in the Alxa metamorphic basement: Evidence;from geochronology
	Geng YuanSheng; Zhou XiWen
刊名	ACTA PETROLOGICA SINICA
	2012
卷号	28 期号:9 页码:2667-2685
关键词	Granitoids Early Permian Zircon U-Pb geochronology Alxa metamorphic basement Cental Asian Orogenic belt
ISSN号	022HC
英文摘要	Abundant weakly-deformed granitoids of Early Permian have been discerned in the Aka metamorphic basement. The zircon LA-ICP-MS and SHRIMP U-Pb dating of the dioritic gneiss (AL0705-1), garnet-bearing tonalitic gneiss (AL0709-1), tonalite (AL0718-1), streaky biotite-plagioclase gneiss (AL0822-1) and gneissic granite (AL0822-3) collected from the eastern part of the Alia metamorphic basement gives the ages of 270 +/- 1.6Ma, 276 +/- 1.8Ma, 269 +/- 2.4Ma, 276 +/- 2.4Ma and 287 +/- 2.5Ma, respectively. While zircons of the granodioritic gneiss (AL0805-1), dioritic gneiss (AL0805-4), coarse granodioritic gneiss (AL0810-1) and mesograined dioritic gneiss (AL0810-2) collected from the western part of the basement yield ages of 284 +/- 3M, 289 +/- 3Ma, 276 +/- 2Ma and 279 +/- 2Ma, respectively. Notwithstanding the different rock types and chemical compositions, all these Early Permian granitoids formed in a short time gap from 289Ma to 269Ma, suggesting they were of the same magmatic event. In addition, the ages of the granitoids are approximately identical to the Ar-39-Ar-40 plateau ages of hornblendes from the metamorphic rocks in the basement, indicating that the Ar-Ar isotopic system of hornblende from the metamorphic rocks had been reset in the Early Permian magmatic event. The occurrence of the voluminous granitoids of Early Permian in the Alxa metamorphic basement demonstrates that the basement had been strongly involved and reworked in the collision orogeny of the Central Asian Orogenic belt in the Late Paleozoic.
学科主题	火成岩岩石学
WOS关键词	NORTH CHINA CRATON ; ASIAN OROGENIC BELT ; U-PB GEOCHRONOLOGY ; CONTINENTAL ; GROWTH ; CRUSTAL GROWTH ; MARGIN ; AREA ; CONSTRAINTS ; GRANITOIDS ; HEBEI
WOS研究方向	Geology
语种	中文
WOS记录号	WOS:000309947500001
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/39851]
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	Geng YuanSheng,Zhou XiWen. Early Permian magmatic events in the Alxa metamorphic basement: Evidence;from geochronology[J]. ACTA PETROLOGICA SINICA,2012,28(9):2667-2685.
APA	Geng YuanSheng,&Zhou XiWen.(2012).Early Permian magmatic events in the Alxa metamorphic basement: Evidence;from geochronology.ACTA PETROLOGICA SINICA,28(9),2667-2685.
MLA	Geng YuanSheng,et al."Early Permian magmatic events in the Alxa metamorphic basement: Evidence;from geochronology".ACTA PETROLOGICA SINICA 28.9(2012):2667-2685.