浙江新昌地幔岩捕虏体中的硫化物包裹体初步研究

A Study of Sulfide Inclusions of the Mantle Xenoliths from Xinchang, Zhejiang, China

浙江新昌一带晚第三纪碱性玄武岩中地幔岩(二辉橄榄岩)捕虏体内存在大量硫化物熔体包裹体。电子探针分析表明,硫化物相成分主要为镍黄铁矿,次为磁黄铁矿。硫化物包裹体的Ni/Fe值与寄主地幔岩的橄榄石含量呈正相关。同一包裹体的硫化物相成分不均一,自中心至边缘硫化物的Ni/Fe、(Fe+Ni)/S值和Ni含量均呈增加趋势。通过与中国汉诺坝、德国West Eifel和东欧Nograd-Gomor地区资料的综合分析,表明不同地区地幔岩捕虏体中硫化物包裹体成分存在差别,反映了上地幔流体硫化物成分的区域差异。

The discovery of sulfide-melt inclusions in mantle xenoliths is of great significance in further understanding mantle depletion and enrichment, as well as ore-forming processes of mantle fluids. Many sulfide-melt inclusions are also found in lherzolite xenoliths of alkali basalt from the Xinchang area, Zhejiang Province. The EPMA study shows that sulfide phases in sulfide-melt inclusions are mainly composed of pentlandite, with a small amount of pyhrrotite. The Ni/Fe of sulfide inclusions is related to the content of olivine in the host mantle rocks. The composition of a single sulfide inclusion is not homogeneous, with Ni/Fe and (Fe+Ni)/S increasing from the center to the margin. Based on comparisons with sulfide-melt inclusion data from Hannuoba of China, West Eifel of Germany and Nogrod-Gomor of Northern Hungary and Southern Slovak, it may be considered that the compositions of sulfide-melt inclusions from different areas are various , showing regional characteristics in the sulfide compositions of mantle fluids.