Metamorphic P-T conditions and U-Pb dating of the sillimanite-cordierite-garnet paragneisses in Sanchakou, Jining area, Inner Mongolia

	Metamorphic P-T conditions and U-Pb dating of the sillimanite-cordierite-garnet paragneisses in Sanchakou, Jining area, Inner Mongolia
	Cai Jia 2; Liu FuLai ; Liu PingHua ; Shi JianRong
刊名	ACTA PETROLOGICA SINICA
	2014
卷号	30 期号:2 页码:472-490
关键词	Metapelites Phase equilibria modeling U-Pb dating Paleoproterozoic Sanchakou Jining area
ISSN号	1000-0569
英文摘要	Sanchakou sillimanite-cordierite-garnet paragneisses, showing distinct decompressional textures, crop out in lining Complex in the eastern segment of the Khondalite Belt, the North China Craton (NCC). The mineral assemblages and microtextures of the Sanchakou sillimanite-cordierite-garnet paragneisses allow a reconstruction of the metamorphic history of the area. The rocks contain two distinct metamorphic assemblages according to the systematic petrographic observations and mineral chemistry, namely the peak (M-1) and the post-peak (M-2) stages. The peak (M-1) assemblage consists of garnet (mantle) + sillimanite + biotite + quartz + plagioclase + K-feldspar + ilmenite +/- magnetite. Post-peak near-isothermal decompressional (M-2) stage following the peak stage could be subdivided into two stages M2-1 and M2-2. The M2-1 stage is characterized by garnet and the development of cordierite + sillimanite + quartz + plagioclase + K-feldspar + ilmenite +/- spinel corona, and the M2-2 stage is represented by garnet + cordierite + biotite + quartz + plagioclase + K-feldspar + ilmenite + magnetite +/- spinal, involving the reactions of garnet + sillimanite + melt -> cordierite + biotite + Fe-oxide and garnet + sillimanite -> cordierite + spinel. Quantitative phase equilibria modeling in the system Na2O-CaO-K2O-FeO-MgO-Al2O3-SiO2-H2O-TiO2-Fe2O3 in combination with traditional thermobarometry, was applied to obtain P-T conditions of 852 similar to 862 degrees C and 9.3 similar to 10.2kbar for M-1, 854 similar to 880 degrees C and 7.0 similar to 7.4kbar for M2-1, 820 similar to 848 degrees C and 5.3 similar to 6.4kbar for M2-2. The combination of the mineral assemblages, mineral compositions, and metamorphic reaction histories in the Sanchakou sillimanite-cordierite-garnet paragneisses defines a clockwise P-T path that involves near-isothermal decompression that followed the peak granulite-facies metamorphism. Cathodoluminescent images show that zircons contained in the Sanchakou sillimanite-cordierite-garnet paragneisses mostly are metamorphic zircons. Analyses of LA-ICP-MS zircon U-Pb dating indicate that metamorphic zircons recorded concordant Pb-207/Pb-206 ages, and metamorphic age of the sillimanite-cordierite-garnet paragneisses is 1912 +/- 11Ma. The clockwise P-T path reveals that the Jining terrane involved in the subduction or collision followed by exhumation and cooling events and experienced the Paleoproterozoic (similar to 1912Ma) granulite-face metamorphism to form the Khondalite Belt with the amalgamation of the Yinshan and the Ordos blocks in the Western Block of the North China Craton.
学科主题	变质岩岩石学
WOS关键词	NORTH CHINA CRATON ; ULTRAHIGH-TEMPERATURE METAMORPHISM ; MAJOR TECTONIC UNITS ; EASTERN GHATS BELT ; KHONDALITE BELT ; WESTERN BLOCK ; METAPELITIC GRANULITES ; REGIONAL METAMORPHISM ; CRUSTAL METAMORPHISM ; KEY ISSUES
WOS研究方向	Geology
语种	中文
出版者	SCIENCE PRESS
WOS记录号	WOS:000333224500012
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/40487]
专题	中国地质科学院地质研究所
作者单位	1.Chinese Acad Geol Sci, Inst Geol, Beijing 100037, Peoples R China 2.中国地质科学院地质研究所
推荐引用方式 GB/T 7714	Cai Jia,Liu FuLai,Liu PingHua,et al. Metamorphic P-T conditions and U-Pb dating of the sillimanite-cordierite-garnet paragneisses in Sanchakou, Jining area, Inner Mongolia[J]. ACTA PETROLOGICA SINICA,2014,30(2):472-490.
APA	Cai Jia,Liu FuLai,Liu PingHua,&Shi JianRong.(2014).Metamorphic P-T conditions and U-Pb dating of the sillimanite-cordierite-garnet paragneisses in Sanchakou, Jining area, Inner Mongolia.ACTA PETROLOGICA SINICA,30(2),472-490.
MLA	Cai Jia,et al."Metamorphic P-T conditions and U-Pb dating of the sillimanite-cordierite-garnet paragneisses in Sanchakou, Jining area, Inner Mongolia".ACTA PETROLOGICA SINICA 30.2(2014):472-490.