Timing of Anatexis within the Berere HTHP Complex Belt of Maevatanana Area,North-Central Madgascar,and its Geological Significance

作     者：LI Peng LIU Shanbao LI Jiankang SHI Guanghai LIU Xiang LI Peng;LIU Shanbao;LI Jiankang;SHI Guanghai;LIU Xiang

作者机构：MNR Key Laboratory of Metallogeny and Mineral AssessmentInstitute of Mineral ResourcesChinese Academy of Geological SciencesBeijing 100037China State Key Laboratory of Geological Processes and Mineral ResourcesChina University of GeosciencesBeijing 100083China Hunan Nuclear GeologyChangsha 410011China 

出 版 物：《Acta Geologica Sinica(English Edition)》 (地质学报（英文版）)

年 卷 期：2020年第94卷第5期

页      面：1393-1409页

核心收录：

学科分类：070904[理学-构造地质学] 070902[理学-地球化学] 0709[理学-地质学] 07[理学] 

基　　金：funded by the National Key R&D Program of China(grant numbers 2019YFC0605202 and 2019YFC0605203) Geological Survey Project grants from the China Geological Survey(grant numbers 12120113102100,DD20160056) Research Program of Department of Land and Resources of Hunan Province(grant number 2018-02) the Chinese National Non-Profit Institute Research Grant of CAGS-IMR(grant number IMRKK1927) the National Natural Science Foundation of China(41872096) the Chinese National Non-profit Institute Research Grant of CAGS(JYYWF201814) 

主　　题：anatexis felsic leucosome U-Pb zircon dating Lu-Hf isotope Madagascar 

摘      要：The Berere HTHP Complex belt in Maevatanana area of north–central Madagascar formed in the^2.5 Ga orogeny and underwent high temperature(up to 1050℃)and high pressure(up to 11.5 kbar)granulite facies *** a widespread anatexis took place and numerous widely distributed felsic leucosomes *** majority of these leucosomes are parallel to the schistosity of the complex or are present as stockworks,as thin layers,or as lenses at different scales in the host ***,we report new petrographic data,zircon LA-ICP-MS U-Pb ages,and Lu–Hf isotopic data for felsic leucosomes within this ***,as identified by the petrological study of felsic leucosomes in the field and in thin sections,involved initial ternary feldspar exsolving to produce antiperthite and a quartz+plagioclase±K-feldspar+sericite mineral assemblage around feldspar grain *** is apparent along muscovite grain boundaries,and residual sericite is present around the margins of feldspar and quartz,all suggesting that anatexis was driven by reactions involving *** U–Pb dating indicates that the felsic leucosomes within the complex formed at 2467–2369 *** majority of samples have positiveεHf(t)values,although a few have negative values,suggesting their formation from magmas predominantly sourced from the depleted mantle,possibly with the involvement of minor amounts of crustal ***-stage Hf model ages andεHf(t)values for these samples are consistent with those for gneisses of the basement,indicating that the felsic leucosomes were formed by the anatexis of gneisses and both of their protolith formed during the formation of continental crust in Meso-Neoarchean(ca.3.1–2.7 Ga).As such,the crystallization age of the felsic leucosome(~2.4 Ga)represents the timing of regional anatexis and a change to post-orogenic *** this anatexis is also corresponds to the thermal event in Dharwar craton in India which has a pronounced similar Precambri