LITHOCHEMISTRY AND TECTONIC SETTING OF THE NEOARCHEAN METAMORPHIC PLUTONIC ROCKS IN EASTERN LIAONING REGION

The Neoarchean rocks in Eastern Liaoning form the basement of North China landmass, which is divided by the Paleoproterozoic Liaoning-Jilin rift into two micro-landmasses in north and south. The northern micro-landmass is composed of Fujiapuzi gneiss complex (U-Pb 2730 Ma), Huzhuang gneiss (U-Pb 2524.85 Ma) and Lianshanguan granite (U-Pb 2563 Ma). The southern micro-landmass consists of Desheng gneiss complex (U -Pb 2591 Ma). The northern microlandmass geochemically presents the characteristics of shoshonite series-sodic calc-alkaline series, belonging to LREE enriched type with positive to negative Eu anomalies. The magma evolved from sodic calc-alkaline to potassic calc-alkaline series. The tectonic setting is active continental margin, with crustal evolution from extension in early orogenic period to compression in major orogenic period. The geochemistry of the rocks in the southern micro-landmass is characterized by high Al and Mg, which is similar to that of adakite, with low total REE, belonging to LREE enriched type with negative Eu anomaly. The magmatic evolution shows sodic trend. The existence of adakite in the southern micro-landmass suggests that the southern micro-landmass subducted northward around 2500 Ma, forming the united Archean continent in Eastern Liaoning region.