Age of the metamorphic sole of the Papuan Ultramafic Belt ophiolite, Papua New Guinea

Lus, W. Y., McDougall, I. and Davies, H. L. (2004) Age of the metamorphic sole of the Papuan Ultramafic Belt ophiolite, Papua New Guinea. Tectonophysics, 392 1-4: 85-101. doi:10.1016/j.tecto.2004.04.009


Author Lus, W. Y.
McDougall, I.
Davies, H. L.
Title Age of the metamorphic sole of the Papuan Ultramafic Belt ophiolite, Papua New Guinea
Journal name Tectonophysics   Check publisher's open access policy
ISSN 0040-1951
Publication date 2004-11-08
Sub-type Article (original research)
DOI 10.1016/j.tecto.2004.04.009
Open Access Status Not Open Access
Volume 392
Issue 1-4
Start page 85
End page 101
Total pages 17
Editor H. Thybo
J. P. Burg
M. Sandiford
Place of publication Amsterdam, The Netherlands
Publisher Elsevier
Language eng
Subject 0403 Geology
0404 Geophysics
Formatted abstract
The Papuan Ultramafic Belt (PUB) ophiolite is former oceanic crust and upper mantle emplaced onto continental crust in Papua New Guinea (PNG) in a zone of general convergence between the Pacific and Australian plates. The metamorphic sole beneath the ophiolite is best exposed in the Musa-Kumusi divide and comprises a 40- to 300-m-thick body of granulite and amphibolite facies rocks. Geochronological studies on the metamorphic sole, using amphiboles from the granulites and amphibolites, yield measured K-Ar ages ranging from 65.0±0.7 to 57.2±0.6 Ma and average 40Ar-39Ar direct total fusion ages ranging from 67.0±0.7 to 59.5±0.2 Ma. Five of the six 40Ar-39Ar plateau ages, derived from age spectra, lie between 58.6±0.2 and 57.8±0.2 Ma, with an overall mean age of 58.3±0.4 Ma. The large spread in measured K-Ar and 40Ar-39Ar total fusion ages is thought to be caused by the presence of variable amounts of excess argon. The mean plateau age for five samples of 58.3±0.4 Ma is interpreted to mark the time of cooling of the metamorphic sole following peak metamorphism. We suggest that the development of the metamorphic sole and emplacement of the PUB ophiolite onto the PNG crust occurred in a relatively short time interval in the Paleocene.
© 2004 Elsevier B.V. All rights reserved.
Keyword Geochronology
Metamorphic sole
Obduction
Ophiolite
Papua
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
School of Earth Sciences Publications
 
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