Authors / CoAuthors
Johnson, R.W. | Smith, I.E.M. | Taylor, S.R.
Abstract
Four distinct volcanic rock types are found above a conjectured mantle hot spot in St Andrew Strait, northern Papua New Guinea. Hypersthene-normative basalts on Baluan Island are geochemically similar in most respects to those on oceanic islands and, together with voluminous alkali-rich rhyolites on Tuluman, Lou, and Pam Islands, constitute a strongly bimodal rock suite. The rhyolites are regarded as partial melts of basaltic crust isotopically similar to the basalts of Baluan, though with lower Sr, Rb, and Ba contents. In contrast, quartz-tholeiite basalts in the Fedarb Islands are isotopically distinct from the Baluan basalts. Dacite is also present in the Fedarb Islands, but not all of its geochemical features are consistent with a derivation by crystal fractionation from Fedarb quartz tholeiite. Like Iceland, St Andrew Strait may be underlain by a hot mantle diapir that has produced basaltic magmas as well as partial melting of basaltic crust.
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document
eCat Id
80945
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
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Keywords
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- GA PublicationJournal
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- PNG
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_External
Publication Date
1978-01-01T00:00:00
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geoscientificInformation
Series Information
BMR Journal of Australian Geology and Geophysics 3:1:55-69
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Unknown
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Extents
[-2.6, -2.3, 147.2, 147.5]
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