米仓山地区晋宁期基性超基性侵入岩中造岩矿物研究

米仓山地区晋宁期基性超基性侵入岩形成于弧后海盆地环境 ,是扬子板块北缘晋宁期造山构造岩浆旋回早期阶段岩浆活动产物 ,具有层状侵入体的特征。其主要造岩矿物为橄榄石、斜方辉石、单斜辉石、斜长石和角闪石。对这些矿物的产出状态和化学成分进行了详细研究 ,确定了矿物种属 ;并根据主要造岩矿物特征探讨了米仓山地区晋宁期基性超基性岩的原始岩浆性质、来源、成岩条件及其构造背景。

STUDY ON ROCK-FORMING MINERALS IN THE BASIC-ULTRABASIC ROCKS OF JINNING PERIOD FROM THE MICANGSHAN AREA

The basic ultrabasic rocks of Jinning Period from the Micangshan area formed in the setting of back arc basin. They are the products of the magmatic activity during the early stage of Jinning Period tectonomagmatic cycle along the northern margin of the Yangtze Plate. They show layered intrusion features. The major rock forming minerals include olivine, orthopyroxene, clinopyroxene, plagioclase and amphibole. In this paper, the occurence state and chemical composition of the minerals are studied in detial. Based on the above, the initial magmatic property and source, the diagenetic conditions and formation environment of the intrusive rocks are further discussed.