A granulite facies kalsilite-leucite-hibonite association from Punalur, Southern India

Abstract

Kalsilite, leucite and hibonite occur together with spinel, corundum, sphene, perovskite, Ti-phlogopite and K-feldspar in a granulite facies gneiss in the Punalur district in Kerala, southern India. Kalsilite-leucite-perovskite-phlogopite and kalsilite-hibonite-spinelcorundum formed distinct, texturally equilibrated assemblages during the granulite facies metamorphism. Sphene occurs as coronas on perovskite suggesting the retrograde breakdown of the perovskite-leucite association; leucite is partially altered to symplectites of K-feldspar and kalsilite, while hibonite shows partial replacement by corundum and perovskite in spinel-rich domains. Unlike other terrestrial hibonites the majority ..