Clinopyroxene relict magmatic phases in Neoarchean Mangikhuta volcanics are described in detail in terms of their geochemistry for the first time, and their petrogenetic insights obtained. EPMA study indicates their restricted compositional range. Elemental variation diagrams show progressive variation of Al, Ca, Si, Fe+3, Ti, Cr, Aly and Aly/Alz, Ti/Al, Fe+2/Fe+3 elemental ratios with fractionation, which establishes their equilibrium conditions during crystallization differentiation. On pyroxene quadrilateral, they plot along fractionation trend of augite. Ca-Al Tschermak, esseneite and Tp are the “other components” in these clinopyroxenes. Progressive variation of other components indicates decrease of pH2O and fO2 of the magma during fractionation. Other components of clinopyroxenes and chondrite normalized whole rock REE patterns indicate minor fractionation of plagioclase in primitive magma. However, plagioclase became a major precipitating phase in later stage of fractionation. Clinopyroxene geobarometer and geothermometer indicate 0–3 kb pressure and 1100–1250° C temperature of crystallization of Mangikhuta clinopyroxenes. Mangikhuta complex have typically high normative orthopyroxene content (35–45 vol. %) now altered to Mg-Al-Fe chlorite. The Mangikhuta magma was highly aqueous and after genesis, it ascended rapidly giving rise to silica-alumina-calc-alkaline series rocks. In the late magmatic history, there was reaction between orthopyroxene and water and plagioclase and water so that Mg(Al,Fe)SiO3 pyroxene converted to Mg(Fe, Al) chlorite and prehnite.

中文翻译：

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印度中部 Dongargarh 超群新太古代 Mangikhuta 火山复合体的岩石成因：来自残余单斜辉石化学的见解

首次从地球化学方面详细描述了新太古代曼吉胡塔火山岩中的单斜辉石残渣岩浆相，并获得了其成因认识。EPMA 研究表明它们的成分范围有限。元素变化图显示了 Al、Ca、Si、Fe+3、Ti、Cr、Aly 和 Aly/Alz、Ti/Al、Fe+2/Fe+3 元素比例随分馏的逐渐变化，从而建立了它们在结晶过程中的平衡条件分化。在辉石四边形上，它们沿着辉石的分馏趋势绘制。Ca-Al Tschermak、辉石和 Tp 是这些单斜辉石中的“其他成分”。其他组分的逐渐变化表明在分馏过程中岩浆的 pH2O 和 fO2 降低。单斜辉石和球粒陨石的其他成分归一化的全岩 REE 模式表明原始岩浆中斜长石的轻微分馏。然而，斜长石成为分馏后期的主要沉淀相。单斜辉石地球气压计和地温计显示 Mangikhuta 单斜辉石的结晶温度为 0-3 kb 压力和 1100-1250°C。Mangikhuta 复合体通常具有较高的标准斜方辉石含量（35–45 vol.%），现在已转变为 Mg-Al-Fe 绿泥石。曼吉胡塔岩浆含水量高，成因后迅速上升，形成硅铝钙碱性系列岩石。在岩浆发育晚期，斜辉石与水、斜长石与水发生反应，使Mg(Al,Fe)SiO3辉石转化为Mg(Fe,Al)绿泥石和孕黄长石。