GEOLOGICAL CHARACTER AND SIGNIFICANCE OF ADAKITE AND TTG IN XIAONANGOU-MINGXINGGOU DISTRICT IN CENTRAL OF INNER MONGOLIA

Abstract

A suit of schistositied quartz diorite and schistositied tonalite in Neoarchean, which is exposed in Xiaonangou-Mingxinggou district in central of Inner Mongolia. Petrochemical contents show that it possesses high contents of SiO2, Al2O3, Na2O,Ba,Sr,Mg#,LREE and low contents of Yb,Y,HREE, and it possess the character of Adakite and TTG. It is associated intently with greenstone of Seertengshan Group Neoarchean in space distribution. The two isochronal age of zircon in quartz diorite are 2575 ± 1Ma (U-Pb) and 2541 ± 30Ma (U-Pb), it is formed by partial melting of ocean slab which formed on the belt of plate subduction in Neoarchean. It possesses important significance in studying early Earth evolution and origin of plate tectonics.