Pliocene eclogite exhumation at plate tectonic rates in eastern Papua New Guinea

Suzanne L. Baldwin, Brian B. Monteleone, Laura E. Webb, Paul G. Fitzgerald, Marty Grove, E. June Hill

Research output: Contribution to journalArticle

176 Scopus citations

Abstract

As lithospheric plates are subducted, rocks are metamorphosed under high-pressure and ultrahigli-pressure conditions to produce eclogues and eclogite facies metamorphic rocks. Because chemical equilibrium is rarely fully achieved, eclogites may preserve in their distinctive mineral assemblages and textures a record of the pressures, temperatures and deformation the rock was subjected to during subduction and subsequent exhumation. Radioactive parent-daughter isotopic variations within minerals reveal the timing of these events. Here we present in situ zircon U/Pb ion microprobe data that dates the timing of eclogite facies metamorphism in eastern Papua New Guinea at 4.3 ± 0.4 Myr ago, making this the youngest documented eclogite exposed at the Earth's surface. Eclogite exhumation from depths of ∼75 km was extremely rapid and occurred at plate tectonic rates (cm yr-1). The eclogite was exhumed within a portion of the obliquely convergent Australian-Pacific plate boundary zone, in an extending region located west of the Woodlark basin sea floor spreading centre. Such rapid exhumation (>1 cm yr-1) of high-pressure and, we infer, ultrahigh-pressure rocks is facilitated by extension within transient plate boundary zones associated with rapid oblique plate convergence.

Original languageEnglish (US)
Pages (from-to)263-267
Number of pages5
JournalNature
Volume431
Issue number7006
DOIs
StatePublished - Sep 16 2004

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