Petrology across a calcareous rock–anorthosite interface from the Chilka Lake Complex, Orissa: Implications for Neo-Proterozoic crustal evolution of the northern Eastern Ghats Belt
- 作者：Pulak Sengupta ; Somnath Dasgupta ; Niloy Ranjan Dutta ; Michael M. Raith
- 关键词：Eastern Ghats ; Proterozoic anorthosite ; UHT contact metamorphism ; Pan-African high-grade reworking
- 刊名：Precambrian Research
- 出版年：2008
- 期刊代码：75_03019268
- 类别：ear
- 出版时间：5 April 2008
- 卷：162
- 期：1-2
- 页码：40-58
- 文件大小：2489 K
摘要
Mineral assemblages, reaction textures and consideration of deduced mineral reactions in appropriate petrogenetic grids in calc-silicate rocks occurring at the contact of the 0.79 Ga Chilka Lake anorthosite pluton, northeastern part of the Eastern Ghats Belt, India, reveal UHT-metamorphism (T > 1000 °C) at mid-crustal depths (corresponding to 7 ± 1 kbar). This 0.79 Ga thermal metamorphism completely erased imprints of an earlier (0.96 Ga) granulite facies metamorphism in the calc-silicate rocks. The anorthosite and UHT contact metamorphic rocks were overprinted by amphibolite–granulite facies tectonothermal re-working at 0.69–0.66 Ga. Both the anorthosite-induced UHT metamorphism and the high-grade Pan-African re-working are unique for the Eastern Ghats Belt. These new observations provide clues regarding integration and disintegration of Rodinia and Indo-Antarctic correlation in the Precambrian.