Dioctahedral mixed K-Na-micas and paragonite in diagenetic to low-temperature metamorphic terrains: Bulk rock chemical, thermodynamic and textural constraints
Dioctahedral mixed K-Na-micas and paragonite in diagenetic to low-temperature metamorphic terrains: Bulk rock chemical, thermodynamic and textural constraints
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成岩至低温变质地形中双八面体混合钾钠云母和钠云母：块体岩石化学、热力学和结构约束
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
P. Horváth
中科院分区：
文献类型：
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作者：
P. Árkai;K. Livi;P. Horváth
低温变质碎屑岩中的变质矿物组合常含有副辉石和(或)其前驱体亚稳相(混合K-Na-白色云母)。研究了中欧和东南欧7个地区块体岩石常量元素化学特征与副辉石形成的关系，并与矿物组合、矿物化学和变质岩石学资料进行了对比。不含PG和含PG的变质碎屑岩体化学投影场之间的显著重叠表明，实际(分析时)和有效的块体化学成分之间存在显著差异。在排除继承、碎屑、惰性相/组分的情况下，发现岩石的Na/(Na+Al*)和K/(K+Al*)比值的降低有利于PG及其前体相的形成和赋存(Al*是指长石、白云母和“纯”有水或无水铝硅酸盐中铝的原子量)。相比之下..。
Abstract Metamorphic mineral assemblages in low-temperature metaclastic rocks often contain paragonite and/or its precursor metastable phase (mixed K-Na-white mica). Relationships between the bulk rock major element chemistries and the formation of paragonite at seven localities from Central and SE-Europe were studied, comparing the bulk chemical characteristics with mineral assemblage, mineral chemical and metamorphic petrological data. Considerable overlaps between the projection fields of bulk chemistries of the Pg-free and Pg-bearing metaclastic rocks indicate significant differences between the actual (as analyzed) and effective bulk chemical compositions. Where inherited, clastic, inert phases/constituents were excluded, it was found that a decrease in Na/(Na+Al*) and in K/(K+Al*) ratios of rocks favors the formation and occurrence of Pg and its precursor phases (Al* denotes here the atomic quantity of aluminum in feldspars, white micas and “pure” hydrous or anhydrous aluminosilicates). In contrast ...