新疆北部卡拉麦里富碱花岗岩带的碱性花岗岩与锡矿

ALKALI GRANITES AND TIN DEPOSITS OF THE KALAMAILI AREA,NORTHERN XINJIANG

卡拉麦里碱性花岗岩形成于华力西中晚期，属造山晚期至造山后拉张构造环境下形成的Ａ型花岗岩。其岩石学、岩石化学及地球化学特征与国内外Ａ型花岗岩基本相似。在Ｅｂｙ（１９９２）的Ｅｂ－Ｙ－Ｃｅ与Ｎｂ－Ｙ－３Ｇａ三角图解中，本带碱性花岗岩投影点均落在Ａ２区，表明它是大陆－大陆碰撞作用形成的Ａ２型碱性花岗岩。通过碱性花岗岩与锡矿床时空分布关系及物质组分特征的剖析，碱性花岗岩与锡矿具有不可分割的成因联系。与Ａ２型碱性花岗岩有关的锡矿床，在我国尚属首次发现。

The Kalamaili area in northern Xinjiang is characterized not only by vast occurrence of alkali granites, but also by their close relation with tin deposits. The granites were formed in the middle-late Variscian period, and fall into the A typed one produced in the extensional tectonic background of late and post orogeny. The petrology, petrochemistry and geochemistry of them are similar to that of A-typed granites. On the Nb Y Ce and Nb Y 3Ga plots, the alkali granites fall into A 2 area, which were formed in a continental collision period. Their spatial and temperal distribution shows that the granites have inevitably genetic relations with tin deposits. It is worth mentioning that the tin deposits connected with alkali A 2 granites are the first example ever found in China.