Mineralogy and partial melt textures within an ultramafic-mafic body, Greece
Mineralogy and partial melt textures within an ultramafic-mafic body, Greece
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希腊超镁铁质-镁铁质体内的矿物学和部分熔融结构
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发表时间：
1973
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通讯作者：
M. Menzies
中科院分区：
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作者：
M. Menzies
希腊中部Makrirrakhi地区的超镁铁质-基性岩显示出原始蛇绿岩序列的特征，其中包含枯竭的地幔物质，超镁铁质含有部分熔融结构，可能是由这些部分熔融分离合并而成的基性“岩体”。存在相当大的矿物学变化：无分带橄榄石晶体的组成范围从Fo78-84（基性）到Fo88-92（超基性），斜长石An64-79（基性）到An80-90（超基性），尖晶石从铬尖晶石（超基性）到含铝钛多的尖晶石（基性）不等。超镁铁岩的辉石分布范围有限：En89-92 fs1 - 8 Wo0-2（正辉石）和En48-54 Fs1-10 Wo38-50（斜辉石）。基性岩范围更广，硅铁石En36-65 Fs3-20 Wo33-51含量更丰富。部分熔体分选中的辉石与辉长辉长岩系列中的辉石具有化学亲和性。根据分析数据和构造证据，建立了上地幔部分熔融构造模型，并建立了一套区分部分熔融构造和累积熔融构造的标准。
Ultramafic-mafic rocks from Makrirrakhi, Central Greece exhibit features of an original ophiolite sequence which contains depleted mantle material, ultramafic containing partial melt textures and possibly the mafic “pluton” which resulted from the coalescing of these partial melt segregations. Considerable mineralogical variation exists: unzoned olivine crystals range in composition from Fo78–84 (mafics) to Fo88–92 (ultramafics), plagioclases An64–79 (mafics) to An80–90 (ultramafics) and spinel varies from a chromian spinel (ultramafics) to a more aluminous-titaniferous spinel (mafics). Pyroxenes from the ultramafics display a limited range: En89–92 Fs9–8 Wo0–2 (orthopyroxene) and En48–54 Fs1–10 Wo38–50 (clinopyroxene). Mafic rocks display a greater range being richer in ferrosilite En36–65 Fs3–20 Wo33–51. Pyroxenes from within the partial melt segregations have chemical affinities with those from the gabbrotroctolite series. A model of partial melt within the upper mantle, and, a set of criteria to distinguish partial melt textures from cumulate textures, are developed from analytical data and textural evidence.