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祁连山玉石沟蛇绿岩型铬铁矿是典型的高铬型铬铁矿床。通过对玉石沟铬铁矿和橄榄岩围岩进行原位定距离采样研究表明:全岩高的MgO和低的SiO2含量指示这些蛇纹石化橄榄岩不是简单的部分熔融残余,而是经历了后期的熔体再富集作用。玉石沟近矿橄榄岩尖晶石(Cr#>65)和铬铁矿尖晶石的矿物包裹体化学特征反映矿体和围岩形成于俯冲带上覆岩石圈地幔。距离矿体由近及远,赋矿围岩尖晶石化学成分(Cr#=43.9~77.2,TiO2=0.06%~0.34%)无规律变化。这说明高铬型铬铁矿体成矿所需铬并非来源于围岩,而是与玻安质熔体渗滤有关。尖晶石含水矿物包裹体仅赋存在玉石沟铬铁矿尖晶石与硅酸盐矿物接触部位附近可能揭示了玉石沟铬铁矿体的成因:成矿铬尖晶石在上侵的含水熔体与周围方辉橄榄岩的反应过程中形成聚集。
Yulisigou ophiolite-type chromite in Qilian Mountains is a typical high-chromium chromite deposit. By in situ distance sampling of Jadegoug chromite and peridotite wall rock, the results show that the high rock-full MgO and low SiO2 indicate that these serpentinized peridotites are not simple partial melting remnant, The melt re-enrichment. The chemical characteristics of the mineral inclusions in the Jadegou Peridotite (Cr #> 65) and the chromite spinel reflect that the ore bodies and surrounding rocks are formed in the overlying lithospheric mantle of the subduction zone. From the near and far of the orebody, the spinel chemical composition (Cr # = 43.9 ~ 77.2, TiO2 = 0.06% ~ 0.34%) of the ore-hosting rock changed irregularly. This indicates that the chromite needed for metallogenesis of high-Cr-type chromite ore bodies is not derived from the surrounding rock but rather relates to the glass melt infiltration. The existence of spinel water-bearing mineral inclusions only in the vicinity of the contact parts of jade ditch chromite spinel and silicate minerals may reveal the genesis of jade ditch chromite ore body: the mineralized chromite spinel Aggregation occurs during the reaction of the body with the surrounding hodolites.