Khondalite

Khondalite is the name of a metamorphic Gesteines that has arisen at pressures above 5 kilobars and temperatures between 650 ° and 850 ° C from a clayey sedimentary rocks. The name was first used in 1902 by the geologist TL Walker for rocks from southern India; it is derived from the root of the Khond (also Gond ), which are located in Orissa and parts of Andhra Pradesh. Although the rock name is used mainly for occurring in India metamorphic sedimentary rocks, there are descriptions of these rocks from Antarctica, Burma, Vietnam, and North America. Following the recommendations of the IUGS ​​Subcommission on the Systematics of Metamorphic Rocks khondalite will be referred to as sillimanite granulites, or in the presence of a gneiss texture as sillimanite - paragneiss.

Composition

Features of Khondalits is its high content of aluminum-rich minerals. The main components are quartz and feldspar, and cordierite, and sillimanite. Khondalite usually contain 1 to 5% graphite. Depending on the composition of the parent material before metamorphosis garnet, biotite and orthopyroxene may occur. The texture is usually characterized by a layered alternating dark and light rock parties, with higher proportions of biotite gneiss texture can also occur.