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| Collisional Delamination in New Guinea: The Geotectonics of Subducting Slab Breakoff |
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| | by | Mark Cloos
Benyamin Sapiie
Andrew Quarles van Ufford
Richard J. Weiland
Paul Q. Warren
Timothy P. McMahon
| | Year Published: | 2005 | | Total Pages: | 51 | | ISBN: | 0813724007 | | Product Code: | SPE400 | | The island of New Guinea is primarily the product of the most recent oceanic arc-continent collision on Earth. The mountainous spine, the Central Range, is a 1300-km-long by 100–150-km-wide belt with numerous peaks over 3 km elevation. Deformation that led to creation of the Central Range began when the Australian passive margin entered a north-dipping subduction zone in the Middle Miocene. Collisional tectonism began at 8 Ma and ended at about 4 Ma with a change to strike-slip movements in the core of the range. Delamination of the lithospheric mantle underpinning caused asthenospheric upwelling and magma generation. The shallow intrusion of felsic magmas generated copper and gold ore deposits, the most spectacular of which are concentrated in the Ertsberg mining district in the western Central Range. Regional relationships and fieldwork near the mining district, along with geomechanical reasoning, are the basis for making a detailed reconstruction of the events leading up to, and during, collisional orogenesis |
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