Abstract Diwani Hill granulites occurring on the southern tip of the South Delhi Terrane (SDT) of Aravalli Mobile Belt (AMB), comprises rocks of granulite facies and represent the deeper level of the crust. The SDT represents an admixture of charnockites, granites, calc-granulites and hercynite-quartz-bearing pelitic granulites. The symplectite and corona textures recorded in the hercynite-quartz-bearing granulites from a part of SDT provides a wide spectrum of P-T sensors in support of the petrological evolution. P-T evolution of these hercynite-quartz-bearing granulites has been constrained through the use of THERMOCALC program, conventional thermobarometry, and pseudosection modelling in the NCKFMASHTO model system using Perple_X software. The unification of these three calculations, demonstrates that the hercynite-quartz-bearing granulites experienced peak pressure and temperature at 6.7 kbar and 750 °C, respectively. The textural imprints, multistage reaction textures, P-T pseudosections as well as the application of multi-equilibrium calculation give evidence for decompressive history related to their exhumation. SHRIMP U-Pb chronological results yield ages between 780 and 680 Ma as a time of metamorphic overprint, and the ages between 1591 and 1216 Ma corresponding with detritus derived from magmatic source for hercynite-quartz-bearing granulites. Zircon ages reflect that continental crust in the SDT resulted from the Mesoproterozoic protolith of an igneous origin whereas sedimentary succession was deposited between 1216 and 780 Ma. The present study envisages that the South Delhi basin would have been a remnant of the proto-Mozambique Ocean in NW India which was closed due to subduction. This subduction metamorphosed the sediments of the basin to granulite facies and the rocks were subsequently, uplifted because of the thrust sheet tectonics during the Neoproterozoic times.

中文翻译：

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古吉拉特东北部（印度西北部）迪瓦尼山含海西长石英麻粒岩的变质 P-T 演化

摘要 Diwani Hill麻粒岩出现在阿拉瓦利移动带（AMB）的南德里地体（SDT）南端，由麻粒岩相组成，代表地壳的更深层次。SDT 代表了charnockite、花岗岩、钙质麻粒岩和含辉长岩-石英的泥质麻粒岩的混合物。在来自 SDT 一部分的含海长岩石英麻粒岩中记录的辛辉石和日冕纹理提供了广泛的 PT 传感器，以支持岩石演化。通过使用 THERMOCALC 程序、常规热气压测量法和 NCKFMASHTO 模型系统中使用 Perple_X 软件的假截面建模，这些含岩长岩的麻粒岩的 PT 演化受到限制。这三种计算的统一，表明含铁长石英的麻粒岩分别在 6.7 kbar 和 750 °C 时经历了峰值压力和温度。纹理印记、多级反应纹理、PT 假截面以及多平衡计算的应用提供了与其挖掘相关的减压历史的证据。SHRIMP U-Pb年代学结果显示，780~680 Ma的年龄为变质叠印时间，1591~1216 Ma的年龄对应于岩浆源岩浆岩浆中含石英麻粒岩的碎屑。锆石年龄反映了 SDT 中的大陆地壳是由火成成因的中元古代原岩形成的，而沉积层序则沉积在 1216 至 780 Ma 之间。目前的研究设想，南德里盆地可能是印度西北部原始莫桑比克洋的残余，该洋因俯冲而关闭。这种俯冲使盆地的沉积物变质为麻粒岩相，随后由于新元古代的逆冲片构造使岩石隆升。