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用合成地幔岩为原始材料,在温度1225°C和严格控制氧分压10~(-5)-10~(-12)atm条件下,对上地幔部分熔融作用与铬铁矿预富集关系进行实验研究。实验结果表明:(1)在达到稳态熔融结构时,5％-8％的玄武质硅酸盐熔体主要赋存在矿物三联点之间,它为铬元素从地幔岩中萃取运移和预富集提供了先决条件;(2)在部分熔融过程中原岩的尖晶石和辉石(铬透辉石和顽火辉石)提供的铬元素相结合,形成了富铬尖晶石和铬铁矿(Cr_2O_3可达38％-47％)。上地幔部分熔融作用不仅控制了上地幔岩石类型演化(二辉橄榄岩→方辉橄榄岩→纯橄榄岩),同时它对铬铁矿的预富集起着关键作用。
Synthetic mantle rock was used as raw material to study the relationship between partial melting of the upper mantle and chromite pre-enrichment under the conditions of a temperature of 1225 ° C and a controlled oxygen partial pressure of 10-5 (-10) -12 atm Conduct experimental research. The experimental results show that: (1) 5% -8% basaltic silicate melt mainly exists in the triple point of minerals when reaching the steady-state melt structure, which is the reason for the extraction and transport of chromium from the mantle rock Enrichment provides the preconditions; (2) In the partial melting process, the spinel of raw rock and pyroxene (chromodendron and enstatite) provided by the combination of chromium, forming a chromium-rich spinel and chromite ( Cr_2O_3 up to 38% -47%). The partial melting of the upper mantle not only controls the evolution of the upper mantle rock type (lherzolite → hectorite → dunite), but it also plays a key role in the pre-enrichment of chromite.