Petrological study of granulites from Antarctica-India-Madagascar region and the formation of the Gondwana Supercontinent

冈瓦那超大陆被认为是唯一存在于550-600 Ma的巨型大陆。我们对与南极-南印度-马达加斯加地区相对应的超大陆内部的碰撞造山带进行了野外地质调查，采集了各种高级变质岩和伴生的火成岩样品。详细的岩石学和地质年代学研究表明，该地区对应于一个古缝合带，沿该缝合带识别出各种高压高温变质岩和洋板(蛇绿岩)残留物，特别是来自印度南部的Palghat-Cauvery缝合带。我们还在印度南部和南极洲发现了年龄较老的地块，年龄分别为3.2Ga、2.5Ga和0.7-0.8Ga。这些位于550-600 Ma缝合带内的较老地块可能对应于冈瓦那超大陆合并过程中增加到太古代大陆的微大陆或岛弧。

The Gondwana supercontinent is known as the only mega-continent present at 550-600 Ma. We performed field geological survey of collisional orogenic belts within the supercontinent, which corresponds to Antarctica - South India - Madagascar region, and collected various samples of high-grade metamorphic rocks and associated igneous rocks. Detailed petrological and geochronological studies on the rocks demonstrated that this region corresponds to a paleo-suture zone along which various high-pressure and high-temperature metamorphic rocks as well as remnants of oceanic plates (ophiolites) have been recognized, particularly from the Palghat-Cauvery suture zone in southern India. We also found crustal blocks with older ages of 3.2 Ga, 2.5 Ga, and 0.7-0.8 Ga from southern India and Antarctica. These older blocks within the 550-600 Ma suture zone might correspond to microcontinents or island arcs which accreted to Archean continents during the amalgamation of the Gondwana supercontinent.