Comparison of the garnet-orthopyroxene geobarometer with recent experimental studies, and applications to natural assemblages

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Authors:Harley, Simon L.
Author Affiliations:Primary:
Univ. Tasmania, Dep. Geol., Hobart, Tasmania, Australia
Volume Title:Journal of Petrology
Source:Journal of Petrology, 25(3), p.697-712. Publisher: Clarendon Press, Oxford, United Kingdom. ISSN: 0022-3530
Publication Date:1984
Note:In English. 110 refs.; illus. incl. 1 table
Summary:The experimentally derived garnet-orthopyroxene geobarometer is compared with other work on Al2O3 solubility in orthopyroxene. Garnet-peridotite bodies enclosed in gneisses in the Alps and Norway give P estimates of 20-30 kbar; such P results favour a mantle origin and tectonic replacement model for these bodies. The most recent data relevant to the 'country rock' orthopyroxene eclogites from Norway indicate a P of 18 + or - 8kbar which does not allow discrimination between the in situ model of formation and the tectonic emplacement models. Some suites of crustal granulites give P estimates which are consistent with other data, but this geobarometer may underestimate P in comparison with a previous calibration due to sensitivity to relatively small changes in garnet composition. Results for a diverse suite of samples from a single locality in Enderby Land, Antarctica, are used to illustrate the problems and uncertainities. [R.A.H.]
Subjects:Aluminum oxides; Chain silicates; Experimental studies; Garnet group; Geochemistry; Geologic barometry; Granulites; Igneous rocks; Inclusions; Metamorphic rocks; Metamorphism; Nesosilicates; Orthopyroxene; Orthosilicates; Oxides; P-T conditions; Peridotites; Plutonic rocks; Polymorphism; Pyroxene group; Silicates; Solubility; Ultramafics; Xenoliths; CFMAS; FMAS; Garnet-orthopyroxene geobarometer
Abstract Numbers:85M/0445
Record ID:1985013856
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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