Abstract The Acoje block of the Eocene Zambales ophiolite (NW, Philippines) is a fragment of forearc lithosphere in the Western Pacific and hosts a world-class chromite deposit. The compositions of chromitites, dunites and harzburgites in the block are used to explore origin of ophiolitic chromite deposits during subduction initiation. Chromite grains in these rocks have a large range of Cr# [100 × Cr/(Cr + Al)]. Those in the cpx-rich harzburgites have the lowest Cr# range (15–35). Those in the chromitites have a bimodal Cr# distribution, ~45–48 and 73–76, confirming presence of both high-Al and high-Cr chromitites in the block. Those in the cpx-poor harzburgites and dunites have similar Cr#s, ranging from ~35 to 85. The TiO2 contents of chromite grains are generally

中文翻译：

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菲律宾三描礼士蛇绿岩 Acoje 区块中高铝和高铬铬铁矿矿体的共存：俯冲开始的证据

摘要 始新世三描礼石蛇绿岩（菲律宾西北）的 Acoje 区块是西太平洋弧前岩石圈的一个碎片，拥有世界级的铬铁矿矿床。块内铬铁矿、纯英石和方辉石的组成用于探索俯冲开始过程中蛇绿岩铬铁矿矿床的成因。这些岩石中的铬铁矿颗粒具有大范围的 Cr# [100 × Cr/(Cr + Al)]。富含 cpx 的方辉石具有最低的 Cr# 范围 (15-35)。铬铁矿中的铬铁矿具有双峰 Cr# 分布，~45-48 和 73-76，证实块中同时存在高铝和高铬铬铁矿。贫 cpx 方辉石和纯辉石中的那些具有相似的 Cr#s，范围从~35 到 85。铬铁矿晶粒的 TiO2 含量一般为