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李林安 《青海地质科技情报》1996,(1):16-22
青海省与基性－超基性岩有关的玉石矿，主要包括两类；钙铝榴石质玉和蛇纹石质玉。根据笔者的调查，以及有关的信息资料，本文着重对钙铝榴石质玉的基本特征作一介绍。 相似文献
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新疆坡北基性超基性岩带控岩构造特征及成矿专属性 总被引：7，自引：0，他引：7
新疆坡北基性，超基性岩带位于塔里木板块东北部北山裂谷带内，受裂谷内部白地洼深断裂控制，走向北东东。该断裂西北侧为地幔隆起区，东南侧为一向南倾斜的地幔斜坡，岩带正好位于幔隆与幔坡之间，据同位素年龄资料及侵位地层时代，该岩带应为中，晚石炭世的产物。岩带至少有４－５个侵入期次的辉长岩、橄榄辉长岩、橄榄单辉岩及单辉橄榄岩构成。基性岩以富铝钙、低碱、镁铁比值较高为特征，超基性岩以低铝钙，贫碱的超镁铁质岩为特 相似文献
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Three iron-, titanium-rieh layered basie-ultrabasie intrusives have been described.They occur in an approximately south-north striking belt of tectonie-magmatic complex within an anteklise. Iron and titanium were concentrated in the lower or middle lower parts of these intrusives in the early and middle stages of differentiation, during which 《FeO》 may have played an important role. Intimate spatial and temporal association as well as common petroehemical features (i.e., high iron and titanium contents) have been found between these layered intrusives and the syenite and alkalisyenite plutons. All of these rocks are considered as hypogene produets of the differentiation of the. Omeishan basaltic magma. In other words, the hypogene differentiation of the iron (titanium)-rieh, sub-alkali Omeishan basaltic magma under the same tectonic-geological conditions resulted in the formation of the rock series of layered intrusives (peridotite→iron, titanium-rich ultramafic rocks→iron, titanium-rich gabbro, plagioclasite)→syenite, alkali-syenite. 相似文献