新疆西准噶尔地区蛇绿岩与豆荚型铬铁矿床的成因研究  

STUDY ON THE GENESIS OF OPHIOLITES AND PODIFORM CHROMITE DEPOSITES OF THE WESTERN JUNGGAR AREA, XINJIANG

作　　者：郝梓国 

出　　处：《地球学报》1991年第2期73-83,共11页Acta Geoscientica Sinica

摘　　要：本文将西准噶尔地区蛇绿岩分为两类:一类是变质橄榄岩+辉石岩+辉长岩组合(简称PPG系列),它们遵循富Ca的演化趋势,发育冶金型铬铁矿床;另一类是变质橄榄岩+橄长岩+辉长岩组合(简称PTG系列),它们遵循富Al的演化趋势,发育耐火型铬铁矿床。两类蛇绿岩中变质橄榄岩的成因机制是上地幔岩的部分熔融,而铬铁矿及纯橄岩的出现则是高度熔融的残余;堆积杂岩中出现辉石岩+辉长岩和橄长岩+辉长岩的不同组合则与岩浆房的出露深度和氧化状态有关。The ophiolites in the Western Junggar are divided into two types: one of them is assemblage of metamorphic peridotite + pyroxenite + gabbro (abbreviated to PPG series), the series follows Ca-rich evolutional trend and grew the metallurgical type chromite deposit. Another is that of metamorphic peridotite + troctolite + gabbro (abbreviated to PTG series), the series follows Al-rich evolutional trend and grew the refractory type chromite deposit. Genetic mechanism of metamorphic peridotite in the two type ophiolites is partial melting of the upper mantle peridotite. The podiform chromite deposits and the dunites are residues of the higher degree partial melting. The different rock associations of pyroxenite + gabbro and troctolite + gabbro in the accumulating complex are related to depth of formation of magmatic chambers and oxidation state of magma in the spreading ridge.

关 键 词：蛇绿岩带 西准噶尔 橄榄岩 成因研究 地幔岩 岩石组合 单斜辉石 唐巴勒 科马提岩 斜方辉石 

分 类 号：P5[天文地球—地质学]