Eclogite xenoliths from Wajrakarur kimberlites, southern India

Mineralogical characteristics of eclogite xenoliths from three kimberlite pipes (KL2, P2 and P10) of the Proterozoic Wajrakarur kimberlite field of southern India have been studied. In a rare sample of enstatite eclogite from the KL2 pipe garnet contains microscopic triangular arrays of needles or b...

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Bibliographic Details
Published in:Mineralogy and Petrology
Main Authors: PATEL, SC, RAVI, S, THAKUR, SS, RAO, TK, SUBBARAO, KV
Format: Other/Unknown Material
Language:English
Published: SPRINGER WIEN 2006
Subjects:
Andhra-Pradesh
Anantapur District
High-Pressures
Upper Mantle
Garnet
Clinopyroxene
Chemistry
Yakutia
Pipe
Geothermobarometry
Online Access:http://dspace.library.iitb.ac.in/xmlui/handle/10054/14900
https://doi.org/10.1007/s00710-006-0150-8
http://hdl.handle.net/100/1738
Description
Summary:Mineralogical characteristics of eclogite xenoliths from three kimberlite pipes (KL2, P2 and P10) of the Proterozoic Wajrakarur kimberlite field of southern India have been studied. In a rare sample of enstatite eclogite from the KL2 pipe garnet contains microscopic triangular arrays of needles or blebs of omphacite, enstatite and rutile consistent with an origin by exsolution parallel to the isometric form {111}. Discrete omphacite grains in the sample contain exsolved needles or blebs of enstatite and garnet. Kyanite eclogites are abundant in the KL2 pipe which occasionally show a secondary ring of pure celsian around kyanite grains. Omphacite Na2O contents in the eclogites of the KL2 and P2 pipes are typically between 3 and 6 wt%, and garnet has widely variable composition with end member ranges of Prp22-81Grs0-47AImlO30Sps0-1Adr0-5Uv0-3. Eclogites of the P10 pipe comprise chromian omphacite and garnet. Phase relations in the ACF projection exhibit systematic increase of the Ca-Tschermak's component in omphacite from enstatite eclogite through biminerallic eclogite to kyanite eclogite. Garnet-clinopyroxene Fe-Mg geothermometry yields temperatures mostly in the range of 900-1100 degrees C. A formerly supersilicic nature of garnet in enstatite eclogite as inferred from exsolution mineralogy indicates minimum peak pressure of 5 GPa.

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