A body of komatiitic amphibolite, an enclave within the Archean high‐grade orthogneisses in southern India, shows mild chemical weathering under semiarid conditions. Along fractures, chemical weathering has advanced (Chemical Index of Alteration \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $$[ \mathrm{CIA}\,] =53$$ \end{document} ; CIA of fresh \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $$\mathrm{rock}\,\sim 26$$ \end{document} ) to the extent that secondary Mg‐Fe‐Al clay minerals have formed and the rock has turned brownish red, soft, and fine grained. The weathering process has resulted in the mobilization and redistribution of the so‐called immobile elements Fe, Al, Ti, and REE effected by the nature of secondary mineral formation (talc vs. aluminous clay minerals) and also possibly by soil microbes. In the initial stages of secondary mineral formation, there is a small loss of Fe, Al, and REE (noticeably Eu). However, in the fracture zone as well as in the incipiently altered zone, there is significant REE enrichment, probably effected by different precipitation mechanisms. Mobilized REE may have come from a minor alteration of clinopyroxene.

中文翻译：

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印度南部半干旱条件下角闪岩风化中的主要元素、稀土元素和其他微量元素行为

科马提质角闪岩体是印度南部太古代高品位正方麻岩中的一个飞地，在半干旱条件下显示出温和的化学风化作用。沿着裂缝，化学风化已经发展（化学变化指数 \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{ stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $$ [ \mathrm{CIA}\,] =53$$ \end{document} ; CIA 新鲜 \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage {portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $$\mathrm{rock}\,\sim 26$$ \end{document} ) 到形成次生 Mg-Fe-Al 粘土矿物并且岩石变成棕红色、柔软和细粒的程度。风化过程导致所谓的固定元素 Fe、Al、Ti、和 REE 受次生矿物形成的性质（滑石与铝粘土矿物）的影响，也可能受土壤微生物的影响。在次生矿物形成的初始阶段，Fe、Al 和 REE（尤其是 Eu）有少量损失。然而，在断裂带以及初期蚀变带中，稀土元素显着富集，可能受不同沉淀机制的影响。移动的 REE 可能来自单斜辉石的微小变化。可能受不同降水机制的影响。移动的 REE 可能来自单斜辉石的微小变化。可能受不同降水机制的影响。移动的 REE 可能来自单斜辉石的微小变化。