Abstract:Four unusual varieties of Si-Fe alloys occur in ophiolite along the Yarlung Zangbo River. Podiform chromite deposits are distributed in the hurzburgite facies of the Luobusa ophiolite. The Si-Fe alloys are composed chemically of Fe3Si7, Fe7Si3, Fe6Si4, and Fe4Ti3Si2P, and the associated minerals comprising Fe, FeO, SiO2, Si and Mg silicates occur in chromitite. The intergrowth texture formed by 3 alloys indicate that these alloys have same genesis, and the texture developed in the Si-Fe alloys might be a product of chemical reaction between liquid iron and silicate on the boundary of mantle and core.