Occurrence of kornerupine-bearing granulite from Karimnagar, Andhra Pradesh
2006; Indian Academy of Sciences; Volume: 91; Issue: 5 Linguagem: Inglês
ISSN
0011-3891
Autores Tópico(s)earthquake and tectonic studies
ResumoHere, we report the occurrence of kornerupine–bearing, quartz-free granulite from the Malial area of Karimnagar district, Andhra Pradesh. It occurs as small e nclaves and pods within the granite-gneiss, associated with garnet–orthopyroxene–cordierite–biotite-gneiss. Its mineral assemblage includes kornerupine–cordierite– biotite–spinel, K-feldspar, ilmenite and magnetite. Kornerupine, a hydrated magnesium–aluminium silicate plots on the 4MgO–3Al2O3–4SiO2 (4 : 3 : 4) co mposition along the solid solution join b etween 4 : 3 : 4 and 1 : 1 : 1 (3.5MgO.3.5Al 2O3.3.5SiO2) compos itions. The relative XMg values among various minerals are as follows: cordierite > biotite > kornerupine > spinel. The deduced post-peak metamorphic pressure–temperature conditions of 5 –6 kbar and 650–750°C for the kornerupine–spinel–bearing quartz-free granulites are consistent with the experimental work on stability of kornerupine in the MgO–Al2O3–SiO2–H2O system.
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