新疆黄山地区蛇绿岩块的地质、地球化学特征及构造意义

GEOLOGICAL-GEOCHEMICAL CHARACTERISTICS AND TECTONIC SIGNIFICANCE OF THE OPHIOLITES BLOCK IN HUANGSHAN AREA, XINJIANG

黄山地区镁铁-超镁铁堆积杂岩,岩体小而分异好,岩体边部受构造作用强烈,属蛇绿岩中的堆积杂岩,过渡元素的配分曲线为较明显的“W”型。稀土元素配分曲线为LREE弱富集的平坦型。其中辉长岩单元为高钛型(TiO_2最大值为5.20％),这些均反映了堆积杂岩形成环境为洋中脊,分布于现在的位置是板块运动的结果。结合上述事实,通过沉积建造分析,该区在中石炭统曾存在沟弧盆体系。

The mafic-ultramafic accumulation complexes, in an small scale in the Huangshan area, are well differentiated and affected by intensely tectonic movement at surroundings of the complexes. It is of the complexes formed in the ophiolite. The TE partition curve is obviously of 'W' type, and the REE partition curve is of even type with LREE poorly concentrated. The gabbroite is of high titanium type (the highest Tio2 value of 5. 2%), implying that the complexes formed in the mid-oceanic ridge. The analysis of sedimentary formation suggests the existence of groove-arc-basin system at the middle Carboniferous.