新疆诺尔特地区石炭纪火山岩的成岩机制

诺尔特地区位于阿尔泰北部山区 ,西伯利亚板块西南缘。诺尔特地区石炭纪火山岩赋存于下石炭统红山嘴组中 ,火山岩属钙碱性系列 ,主要是酸性陆相火山岩。火山岩岩浆起源于诺尔特地区中地壳位置 ,成岩物质来源于地壳。痕量元素协变关系、皮尔斯元素比值、元素丰度关系及氧同位素特征的研究表明 ,石炭纪火山岩具有明显的部分熔融成岩机制的特点 ,而结晶分异作用特点不明显 ,无混合作用特点的显示。石炭纪火山岩为部分熔融作用的产物。

FORMING MECHANISM OF CARBONIFEROUS VOLCANIC ROCKS IN THE NURT AREA,XINJIANG

The Nurt area is located in the north of Altay,at the southwest of the Siberia plate. Carboniferous volcanic rocks occur in the Lower Carboniferous Hongshanzui Formation.The volcanic rocks belong to the acidic and calc-alkaline series and their eruption occurred in a land environment.The magma was derived from the middle crust and the material of volcanic rocks originated from the crust. Studies on co-variant relations among trace elements,Pearce's element ratio,element abundance and oxygen isotopes show that the mechanism of formation of Carboniferous volcanic rocks was a partial melting process, instead of a crystallization-differentiation and microsigmatisation process. The Carboniferous volcanic rocks originated from partial melting of the crust.