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

Pownall, Jonathan M.; Hall, Robert; Armstrong, Richard A.; Forster, Marnie A.

Authors

Jonathan M. Pownall

Robert Hall

Richard A. Armstrong

Marnie A. Forster



Abstract

Episodes of ultrahigh-temperature (UHT, ≥900 °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 ∼950 °C at ∼8 kbar pressure. Seram is therefore a possible modern analogue for ancient orogens that incorporate UHT granulites

Journal Article Type Article
Publication Date Apr 1, 2014
Journal Geology
Print ISSN 0091-7613
Electronic ISSN 1943-2682
Publisher Geological Society of America
Peer Reviewed Peer Reviewed
Volume 42
Issue 4
Pages 279-282
APA6 Citation Pownall, J. M., Hall, R., Armstrong, R. A., & Forster, M. A. (2014). Earth's youngest known ultrahigh-temperature granulites discovered on Seram, eastern Indonesia. Geology, 42(4), 279-282. https://doi.org/10.1130/G35230.1
DOI https://doi.org/10.1130/G35230.1
Publisher URL https://pubs.geoscienceworld.org/gsa/geology/article-standard/42/4/279/131491/earth-s-youngest-known-ultrahigh-temperature
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