新疆克拉玛依地区百口泉发现尖晶石橄榄岩

    The discovery of spinel peridotite in Baikouquan area, Karamay, Xinjiang

    • 摘要: 新疆克拉玛依地区出露的早古生代蛇绿混杂岩带规模巨大,岩石单元出露齐全。白碱滩地区的地幔橄榄岩相对比较新鲜,单斜辉石、斜方辉石、尖晶石和橄榄石保存完好。研究表明,白碱滩蛇绿岩就位前,地幔岩发生了大于50km的快速隆升,且没有发生部分熔融。百口泉地区发现的地幔岩普遍遭受了改造,辉石多发生了强烈蚀变(透闪石化),但尖晶石和橄榄石保存较好。百口泉地区出露的地幔岩和白碱滩地幔岩的矿物组成基本一致,表明它们属于同一蛇绿混杂岩带。百口泉蛇绿岩剖面的揭露,将该蛇绿混杂岩带的范围向NE方向延伸了35km。

       

      Abstract: The ophiolitic mélange extensively developed in Karamay area consists of ultramafic lenses (mainly peridotite, pyroxenite), pillow-lava basalts and siliceous rocks. The peridotite in Baijiantan area consists of olivine, clinopyroxene, orthopyroxene and spinel, which are generally fresh. Previous studies suggested a fast uplifting more than 50km without partial melting. This paper reports for the first time the discovery of mantle rocks in Baikouquan area, 35km away from Baijiantan. Pyroxene in Baikouquan peridotite has been widely altered, but olivine and spinel remain relatively fresh. The mantle rock in Baikouquan has the same mineral assemblage as the mantle rocks in Baijiantan area.

       

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