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为完整了解华北克拉通的破坏程度和机制,加深对其西部陆块岩石圈地幔的研究十分重要,而位于华北克拉通西部集宁新生代碱性玄武岩中的地幔橄榄岩包体,为研究人员认识该地区的岩石圈地幔的性质和演化起到指示作用.运用LA-ICPMS和LA-MC-ICP-MS对集宁地区橄榄岩矿物进行原位微区测试,获得其主量、微量元素和Sr同位素成分的数据.根据矿物组成,可以将集宁地区的橄榄岩分为两类:第一类为贫单斜辉石橄榄岩(单斜辉石体积分数小于8%),它们经历了高程度的部分熔融,可能是古老难熔岩石圈地幔的残留;第二类为二辉橄榄岩(单斜辉石体积分数大于13%),其熔融程度低,代表了新生饱满的岩石圈地幔.第一类橄榄岩中单斜辉石REE含量整体偏低且轻微富集LREE,第二类橄榄岩中单斜辉石具有LREE富集和轻微亏损两种配分模式,大部分样品的核边有一定的强不相容元素及Sr同位素组成变化.这些微量元素和同位素特征都表明集宁橄榄岩包体经历过交代作用.(La/Yb)_N和Ti/Eu比值特征表明它们经历过多阶段的交代作用,交代介质有硅酸盐、碳酸盐熔/流体,这些交代介质可能为来源于古亚洲洋板块俯冲时释放的熔/流体.
In order to fully understand the extent and mechanism of the destruction of the North China craton, it is very important to deepen the study on the lithospheric mantle of the western continental block. The mantle peridotite inclusions in the Jining Cenozoic alkaline basalts in the western part of North China Craton, To understand the nature and evolution of the lithospheric mantle in this area, the perovskite-hosted peridotites in Jining area were measured by LA-ICPMS and LA-MC-ICP-MS, and the main and trace elements and Sr isotopic composition data. According to the mineral composition, the peridotites in the Jining area can be divided into two types: the first type is poor monoclinic peridotite (clinopyroxene volume fraction of less than 8%), they experienced high The degree of partial melting may be the remnant of the ancient refractory lithospheric mantle. The second type is lherzolites (the volume fraction of clinopyroxenes is more than 13%), which shows a low degree of melting and represents a newborn lithospheric mantle. In the first type of peridotite, the REE content of the clinopyroxene is generally low and is slightly enriched in LREE. The second type of peridotite has two kinds of ligand-splitting modes, LREE enrichment and slight loss. Most of the sample nuclei have Some strongly incompatible elements and Sr isotopes These trace elements and isotopic characteristics indicate that the intrusive peridotite inclusions have undergone the metasomatism.The characteristics of (La / Yb) _N and Ti / Eu ratios indicate that they have undergone too many stages of metasomatism, , Carbonate melts / fluids, which may be melts / fluids derived from subduction of Paleo-Asian oceanic plates.