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Earth's youngest known ultrahigh-temperature granulites discovered on Seram, eastern Indonesia

Jonathan M. Pownall, Robert Hall, Richard A. Armstrong and Marnie A. Forster
Earth's youngest known ultrahigh-temperature granulites discovered on Seram, eastern Indonesia
Geology (Boulder) (February 2014) 42 (4): 279-282

Abstract

Episodes of ultrahigh-temperature (UHT, > or =900 degrees C) granulite metamorphism have been recorded in mountain belts since the Neoarchean. However, evidence for the tectonic mechanisms responsible for the generation of such extreme thermal conditions is rarely preserved. Here we report the discovery of 16 Ma UHT granulites--the youngest identified at the Earth's surface--from the Kobipoto Mountains of Seram in eastern Indonesia. UHT conditions were produced by a modern tectonic system in which slab rollback-driven lithospheric extension caused core complex-style exhumation of hot subcontinental lithospheric mantle. Overlying continental crust, heated and metamorphosed by exhumed lherzolites, developed spinel + quartz and sapphirine-bearing residual assemblages, shown by phase equilibria modeling to have required temperatures of approximately 950 degrees C at approximately 8 kbar pressure. Seram is therefore a possible modern analogue for ancient orogens that incorporate UHT granulites.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 42
Serial Issue: 4
Title: Earth's youngest known ultrahigh-temperature granulites discovered on Seram, eastern Indonesia
Affiliation: Royal Holloway-University of London, Department of Earth Sciences, Egham, United Kingdom
Pages: 279-282
Published: 20140210
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 29
Accession Number: 2014-014761
Categories: Igneous and metamorphic petrologyGeochronology
Document Type: Serial
Bibliographic Level: Analytic
Annotation: GSA Data Repository item 2014105
Illustration Description: illus. incl. geol. sketch map
S03°07'60" - S03°07'60", E129°30'00" - E129°30'00"
Secondary Affiliation: Australian National University, AUS, Australia
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201410
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