Metamorphic P-T conditions and zircon U-Pb ages of amphibolite in Laojinchang area,southern Jilin Province  

作　　者：LI Meihui ZHENG Changqing LIANG Chenyue 

机构地区：[1]College of Earth Sciences,Jilin University,Changchun 130061,China [2]Key Laboratory of Mineral Resources Evaluation of Northeast Asia,Ministry of Natural Resources,Changchun 130061,China

出　　处：《Global Geology》2024年第2期76-92,共17页世界地质（英文版）

基　　金：Supported by projects of the National Natural Science Foundation of China(Nos.42172213,42372255).

摘　　要：The Longgang Block is one of the most important parts of the eastern North China Craton,characterized by extensive Late Neoarchean(~2.5 Ga)granulite facies metamorphism.However,it remains uncertain whether it was influenced by Paleoproterozoic magmatism-metamorphism.The authors provide a comprehensive analysis of amphibolite in Laojinchang area,southern Jilin Province,through petrographic,geochemical,mineralogical,and zircon dating.The main findings are as follows:The mineral assemblage of amphibolite is Hb+Pl+Cpx+Bi+Kf+Q,characteristic of amphibolite facies;zircon U-Pb dating indicates that the metamorphic age of amphibolite is 1834±33 Ma;the amphibolite has geochemical characteristics of calcium alkaline,with depletion of Nb,Ta,Ti and P.The plagioclase in the amphibolite is oligoclase,belonging to acidic plagioclase.It is speculated that the protolith of the amphibolite is diorite;using geothermobarometer,the peak metamorphic P-T conditions of amphibolite are determined to be 536–593℃/3.4–5.0 kbar,and the post-peak conditions are 429–566℃/1.3–3.1 kbar.The above results indicate that the Paleoproterozoic metamorphism has been superimposed on Longgang Block,linked to a new orogenic event on the northern edge of North China Craton.

关 键 词：North China Craton Longgang Block AMPHIBOLITE Paleoproterozo ic metamorphism 

分 类 号：P588.3[天文地球—岩石学] P597.3[天文地球—地质学] P534.3