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An orthopyroxene–biotite geothermometer and its application in crustal granulites and mantle‐derived rocks
Author(s) -
SENGUPTA P.,
DASGUPTA S.,
BHATTACHARYA P. K.,
MUKHERJEE M.
Publication year - 1990
Publication title -
journal of metamorphic geology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.639
H-Index - 114
eISSN - 1525-1314
pISSN - 0263-4929
DOI - 10.1111/j.1525-1314.1990.tb00465.x
Subject(s) - granulite , geology , biotite , xenolith , geochemistry , facies , mantle (geology) , petrology , geomorphology , paleontology , quartz , structural basin
Using the experimental data on Fe–Mg exchange between orthopyroxene and biotite of Fonarev & Konilov (1986), an orthopyroxene–biotite geothermometer is developed. The thermometer is corrected for mixing of Ti and Al in octahedral sites in biotite and also for non‐ideal mixing of Fe and Mg in orthopyroxene. The thermometer is applied to several amphibolite–granulite transition facies and granulite facies rocks and also to mantle xenoliths. It yields consistent results in rocks of widely varying bulk composition, and highly magnesian mantle xenoliths. This thermometer removes the difficulty of estimating temperature in garnet‐free rocks in high‐grade terrains and also provides independent estimates of temperature in garnet‐bearing assemblages.