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Article: New SW Pacific tectonic model: Cyclical intraoceanic magmatic arc construction and near-coeval emplacement along the Australia-Pacific margin in the Cenozoic

TitleNew SW Pacific tectonic model: Cyclical intraoceanic magmatic arc construction and near-coeval emplacement along the Australia-Pacific margin in the Cenozoic
Authors
KeywordsCenozoic
New Caledonia ophiolite
Northland ophiolite
Papuan Ultramafic Belt (PUB) ophiolite
Suprasubduction zone lithosphere (SSZL)
SW Pacific
Issue Date2008
PublisherAmerican Geophysical Union.
Citation
Geochemistry, Geophysics, Geosystems, 2008, v. 9 n. 3, art. no. Q01710 How to Cite?
AbstractVarious reconstructions of the SW Pacific for the Late Cretaceous and Cenozoic suggest that northeast dipping subduction began in the South Loyalty Basin (SLB) at 55-50 Ma and that subsequent closure of the SLB resulted in the diachronous emplacement of Cretaceous-Paleocene ophiolitic nappes onto the Norfolk Ridge in New Caledonia at 40-34 Ma and in Northland, New Zealand, around 24-21 Ma. A fundamental problem with these models is that they do not account for the fact that NE dipping subduction had already been established offshore Papua New Guinea by at least 65-60 Ma which resulted in the emplacement of the Papuan Ultramafic Belt (PUB) ophiolite at 59-58 Ma. A second issue is that the reconstructions are based largely upon unfounded assumptions as to the age and nature of the basement beneath the Loyalty arc and Three Kings Ridge. Finally, reconstructions of the Northland region are based upon the erroneous assumption that the age of the majority of the igneous component comprising the Northland allochthon is Late Cretaceous-Paleocene, when in fact it is Oligocene. A new model is presented whereby the PUB, New Caledonia, and Northland ophiolites formed and were emplaced in a cyclical fashion above an extensive NE dipping Cenozoic intraoceanic arc system which diachronously propagated (N-S) along the entire eastern margin of the Australian Plate. These "infant arc" ophiolites represent fragments of suprasubduction zone lithosphere (SSZL) generated in the earliest stages of magmatic arc formation that were emplaced shortly after (<20 m.y.) as a result of forearc-Australian Plate collision. Subduction inception was the result of subsidence of older MORB-like lithosphere generated within an extensive "back arc basin" to the east of the Norfolk Ridge during the earliest stages of SLB formation above a southwest dipping Pacific Plate. During emplacement of each ophiolite, a crustal fragment of the older lithosphere was scraped off the NE dipping slab and subsequently back-thrust beneath each ophiolite during its emplacement. Copyright 2008 by the American Geophysical Union.
Persistent Identifierhttp://hdl.handle.net/10722/151274
ISSN
2015 Impact Factor: 2.993
2015 SCImago Journal Rankings: 2.439
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorWhattam, SAen_HK
dc.contributor.authorMalpas, Jen_HK
dc.contributor.authorAli, JRen_HK
dc.contributor.authorSmith, IEMen_HK
dc.date.accessioned2012-06-26T06:19:50Z-
dc.date.available2012-06-26T06:19:50Z-
dc.date.issued2008en_HK
dc.identifier.citationGeochemistry, Geophysics, Geosystems, 2008, v. 9 n. 3, art. no. Q01710en_HK
dc.identifier.issn1525-2027en_HK
dc.identifier.urihttp://hdl.handle.net/10722/151274-
dc.description.abstractVarious reconstructions of the SW Pacific for the Late Cretaceous and Cenozoic suggest that northeast dipping subduction began in the South Loyalty Basin (SLB) at 55-50 Ma and that subsequent closure of the SLB resulted in the diachronous emplacement of Cretaceous-Paleocene ophiolitic nappes onto the Norfolk Ridge in New Caledonia at 40-34 Ma and in Northland, New Zealand, around 24-21 Ma. A fundamental problem with these models is that they do not account for the fact that NE dipping subduction had already been established offshore Papua New Guinea by at least 65-60 Ma which resulted in the emplacement of the Papuan Ultramafic Belt (PUB) ophiolite at 59-58 Ma. A second issue is that the reconstructions are based largely upon unfounded assumptions as to the age and nature of the basement beneath the Loyalty arc and Three Kings Ridge. Finally, reconstructions of the Northland region are based upon the erroneous assumption that the age of the majority of the igneous component comprising the Northland allochthon is Late Cretaceous-Paleocene, when in fact it is Oligocene. A new model is presented whereby the PUB, New Caledonia, and Northland ophiolites formed and were emplaced in a cyclical fashion above an extensive NE dipping Cenozoic intraoceanic arc system which diachronously propagated (N-S) along the entire eastern margin of the Australian Plate. These "infant arc" ophiolites represent fragments of suprasubduction zone lithosphere (SSZL) generated in the earliest stages of magmatic arc formation that were emplaced shortly after (<20 m.y.) as a result of forearc-Australian Plate collision. Subduction inception was the result of subsidence of older MORB-like lithosphere generated within an extensive "back arc basin" to the east of the Norfolk Ridge during the earliest stages of SLB formation above a southwest dipping Pacific Plate. During emplacement of each ophiolite, a crustal fragment of the older lithosphere was scraped off the NE dipping slab and subsequently back-thrust beneath each ophiolite during its emplacement. Copyright 2008 by the American Geophysical Union.en_HK
dc.languageengen_US
dc.publisherAmerican Geophysical Union.-
dc.relation.ispartofGeochemistry, Geophysics, Geosystemsen_HK
dc.rightsGeochemistry, Geophysics, Geosystems. Copyright © American Geophysical Union.-
dc.subjectCenozoicen_HK
dc.subjectNew Caledonia ophioliteen_HK
dc.subjectNorthland ophioliteen_HK
dc.subjectPapuan Ultramafic Belt (PUB) ophioliteen_HK
dc.subjectSuprasubduction zone lithosphere (SSZL)en_HK
dc.subjectSW Pacificen_HK
dc.titleNew SW Pacific tectonic model: Cyclical intraoceanic magmatic arc construction and near-coeval emplacement along the Australia-Pacific margin in the Cenozoicen_HK
dc.typeArticleen_HK
dc.identifier.emailMalpas, J: jgmalpas@hku.hken_HK
dc.identifier.emailAli, JR: jrali@hku.hken_HK
dc.identifier.authorityMalpas, J=rp00059en_HK
dc.identifier.authorityAli, JR=rp00659en_HK
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1029/2007GC001710en_HK
dc.identifier.scopuseid_2-s2.0-59149104470en_HK
dc.identifier.hkuros143839-
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-59149104470&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume9en_HK
dc.identifier.issue3en_HK
dc.identifier.isiWOS:000254531600001-
dc.publisher.placeUnited Statesen_HK
dc.identifier.scopusauthoridWhattam, SA=8264574200en_HK
dc.identifier.scopusauthoridMalpas, J=7006136845en_HK
dc.identifier.scopusauthoridAli, JR=7102266465en_HK
dc.identifier.scopusauthoridSmith, IEM=7404425799en_HK

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