Widespread arc-related melting in the mantle section of the northern Oman ophiolite as inferred from detrital chromian spinels

We examined detrital chromian spinels, in recent river beds, derived from the mantle section to deterrmine whether the mantle
peridotite of the northern Oman ophiolite is of oceanic or arc origin. The Cr-number (= Cr/(Cr + Al) atomic ratio) of the
detrital chromian spinels mostly ranges from 0.4 to 0.8, and more than 60% of them have Cr-numbers higher than 0.6. This indicates
a significant extent of island-arc nature because chromian spinels seldom have Cr-numbers higher than 0.6 in ocean-floor rocks.
The high-Cr-number (>0.6) spinels, which are also low in TiO2 (

本研究对近期河床中由地幔部分析出的碎屑铬铁矿磁铁矿进行了考察，旨在确定北奥曼洋壳地幔辉石岩的成因是海洋型还是岛弧型。碎屑铬铁矿磁铁矿的Cr数（即Cr/(Cr + Al)原子比）大多介于0.4至0.8之间，其中超过60%的Cr数高于0.6。这一结果暗示了显著的岛弧性质，因为铬铁矿磁铁矿在洋底岩石中很少具有高于0.6的Cr数。高Cr数（>0.6）的磁铁矿同样具有低TiO2含量（