内蒙古中部小南沟-明星沟地区新太古代TTG岩系及其地质意义

Geological character and significance of Adakite and TTG in Xiaonangou-Mingxinggou district in central of Inner Mongolia

内蒙古中部小南沟-明星沟地区出露一套新太古代片理化石英闪长岩和片理化英云闪长岩，岩石化学成分富SiO2、Al2O3、Na2O、Ba、Sr、Mg^#和LREE，而贫Yb、Y和HREE，具有Adakite（埃达克岩）及TTG岩系的特征，空间上与新太古界色尔腾山岩群绿岩密切伴生。在石英闪长岩体中获得2组锆石U—Pb等时线年龄为2575±1Ma和2541±30Ma，是新太古代形成于板块消减带之上的洋壳部分熔融产物，对研究该地区地球早期演化和板块构造起源具有重要意义。

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 , Na2 O, 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 .