新疆阿拉套山花岗岩类高εNd值的成因探讨

ORIGIN OF HIGH ￣εNd (t) GRANITES FROM ALATAO MOUNTAIN, XINJIANG

新疆阿拉套山广泛出露的华力西期花岗岩类的一般岩石学和地球化学性质可与我国以及世界上大部分地区出露的花岗岩相类比，但其εＮｄ（ｔ）高，为＋２．２－＋３．２，其中一部分花岗岩的８７Ｓｒ／８６Ｓｒ（ｔ）也高，可达０．７１５。这可能是壳幔物质ＡＦＣ式混合的结果，也可能是准噶尔地块及其两缘特殊地质环境的反映。

ariscan granitic intrusions are widely outcropped in Alatao Mountain,Northwest Xinjiang. Petrologic and many geochemical characteristics of these granites are very similar to those of most granites of the world. But εNd (t) values of these granites are high, ranging from + 2. 2 to + 3. 2, meanwhile εSr, (t) of some of these granites are also high, up to 150. Granitoids with both high εNd(t) and εSr(t )are rare in the world. As most hight εNd (t ), hight εSr (t ) granitoids, granites of the Alatao Mountain are formed by AFC processes and in a special (extensional and /Or postorogenic) geological setting.