Tectono-thermal evolution of ultrahigh-temperature- (UHT-) metamorphic rocks in the Madurai Block of the Southern Granulite Terrane (southern India)

南印度盾构变质岩被认为是地球动力学过程的最佳档案，是重建印度次大陆前寒武纪地壳演化的宝贵工具。马杜莱地块是印度南部南部麻粒岩地体的一部分，由多种岩石类型组成，包括基性麻粒岩、绿绿岩、含蓝宝石麻粒岩、钙麻粒岩、石英岩、细斑岩、片麻岩、混辉岩等。特别重要的是含蓝宝石/孔雀石的麻粒岩，因为它们保留了变质结晶沿阻滞结构的进阶路径的特征，因此是推导变质作用P-T轨迹的潜在工具。迄今为止，马杜赖地块的超高温（UHT）变质作用的性质和原因仍未得到解决，文献中提出的P-T路径模型相互矛盾。结合伪剖面的建模，计划对捕获反应结构进行详细的结构和岩石学分析。这种方法将为不同的演化阶段产生不同的P-T段，从而将提供一个更完整的描述，特别是这个超高温变质复合体的地球动力学演化，并将有助于更好地理解一般的超高温变质复合体。

The metamorphic rocks of the Southern Indian Shield are considered as the best archive for geodynamic processes and serve as a valuable tool for the reconstruction of Precambrian crustal evolution in the Indian sub-continent. The Madurai Block constitutes part of the Southern Granulite Terrane in southern India and is made up of a variety of rock types, including mafic granulite, charnockite, sapphirine-bearing granulite, calc-granulite, quarzite, leptynite, gneisses, migmatite, etc. Of particular significance are sapphirine/kornerupine-bearing granulites because they preserve signatures of metamorphic crystallization along the prograde path through arrested textures and are thus potential tools for the derivation of the P-T trajectory of metamorphism. To date, the nature and cause of ultrahigh-temperature- (UHT-) metamorphism in the Madurai Block remain unresolved, with conflicting models of P-T paths presented in the literature. Detailed textural and petrological analyses of arrested reaction textures are planned, in combination with the modeling of pseudosections. Such an approach will yield distinct P-T segments for various evolutionary stages and will thus provide a far more complete description of the geodynamic evolution of this UHT metamorphic complex in particular and will contribute to a better understanding of UHT metamorphic complexes in general.