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Article: Link between SSZ ophiolite formation, emplacement and arc inception, Northland, New Zealand: U-Pb SHRIMP constraints; Cenozoic SW Pacific tectonic implications

TitleLink between SSZ ophiolite formation, emplacement and arc inception, Northland, New Zealand: U-Pb SHRIMP constraints; Cenozoic SW Pacific tectonic implications
Authors
KeywordsNorthland arc
Northland ophiolite
SHRIMP
South Fiji Basin
SSZ lithosphere (SSZL)
SW Pacific
Issue Date2006
PublisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/epsl
Citation
Earth And Planetary Science Letters, 2006, v. 250 n. 3-4, p. 606-632 How to Cite?
AbstractNew U-Pb age-data from zircons separated from a Northland ophiolite gabbro yield a mean 206Pb/ 238U age of 31.6 ± 0.2 Ma, providing support for a recently determined 28.3 ± 0.2 Ma SHRIMP age of an associated plagiogranite and ∼ 29-26 Ma 40Ar/ 39Ar ages (n = 9) of basalts of the ophiolite. Elsewhere, Miocene arc-related calc-alkaline andesite dikes which intrude the ophiolitic rocks contain zircons which yield mean 206Pb/ 238U ages of 20.1 ± 0.2 and 19.8 ± 0.2 Ma. The ophiolite gabbro and the andesites both contain rare inherited zircons ranging from 122-104 Ma. The Early Cretaceous zircons in the arc andesites are interpreted as xenocrysts from the Mt. Camel basement terrane through which magmas of the Northland Miocene arc lavas erupted. The inherited zircons in the ophiolite gabbros suggest that a small fraction of this basement was introduced into the suboceanic mantle by subduction and mixed with mantle melts during ophiolite formation. We postulate that the tholeiitic suite of the ophiolite represents the crustal segment of SSZ lithosphere (SSZL) generated in the southern South Fiji Basin (SFB) at a northeast-dipping subduction zone that was initiated at about 35 Ma. The subduction zone nucleated along a pre-existing transform boundary separating circa 45-20 Ma oceanic lithosphere to the north and west of the Northland Peninsula from nascent back arc basin lithosphere of the SFB. Construction of the SSZL propagated southward along the transform boundary as the SFB continued to unzip to the southeast. After subduction of a large portion of oceanic lithosphere by about 26 Ma and collision of the SSZL with New Zealand, compression between the Australian Plate and the Pacific Plate was taken up along a new southwest-dipping subduction zone behind the SSZL. Renewed volcanism began in the oceanic forearc at 25 Ma producing boninitic-like, SSZ and within-plate alkalic and calc-alkaline rocks. Rocks of these types temporally overlap ophiolite emplacement and subsequent Miocene continental arc construction. © 2006 Elsevier B.V. All rights reserved.
Persistent Identifierhttp://hdl.handle.net/10722/73036
ISSN
2015 Impact Factor: 4.326
2015 SCImago Journal Rankings: 3.628
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorWhattam, SAen_HK
dc.contributor.authorMalpas, Jen_HK
dc.contributor.authorSmith, IEMen_HK
dc.contributor.authorAli, JRen_HK
dc.date.accessioned2010-09-06T06:47:26Z-
dc.date.available2010-09-06T06:47:26Z-
dc.date.issued2006en_HK
dc.identifier.citationEarth And Planetary Science Letters, 2006, v. 250 n. 3-4, p. 606-632en_HK
dc.identifier.issn0012-821Xen_HK
dc.identifier.urihttp://hdl.handle.net/10722/73036-
dc.description.abstractNew U-Pb age-data from zircons separated from a Northland ophiolite gabbro yield a mean 206Pb/ 238U age of 31.6 ± 0.2 Ma, providing support for a recently determined 28.3 ± 0.2 Ma SHRIMP age of an associated plagiogranite and ∼ 29-26 Ma 40Ar/ 39Ar ages (n = 9) of basalts of the ophiolite. Elsewhere, Miocene arc-related calc-alkaline andesite dikes which intrude the ophiolitic rocks contain zircons which yield mean 206Pb/ 238U ages of 20.1 ± 0.2 and 19.8 ± 0.2 Ma. The ophiolite gabbro and the andesites both contain rare inherited zircons ranging from 122-104 Ma. The Early Cretaceous zircons in the arc andesites are interpreted as xenocrysts from the Mt. Camel basement terrane through which magmas of the Northland Miocene arc lavas erupted. The inherited zircons in the ophiolite gabbros suggest that a small fraction of this basement was introduced into the suboceanic mantle by subduction and mixed with mantle melts during ophiolite formation. We postulate that the tholeiitic suite of the ophiolite represents the crustal segment of SSZ lithosphere (SSZL) generated in the southern South Fiji Basin (SFB) at a northeast-dipping subduction zone that was initiated at about 35 Ma. The subduction zone nucleated along a pre-existing transform boundary separating circa 45-20 Ma oceanic lithosphere to the north and west of the Northland Peninsula from nascent back arc basin lithosphere of the SFB. Construction of the SSZL propagated southward along the transform boundary as the SFB continued to unzip to the southeast. After subduction of a large portion of oceanic lithosphere by about 26 Ma and collision of the SSZL with New Zealand, compression between the Australian Plate and the Pacific Plate was taken up along a new southwest-dipping subduction zone behind the SSZL. Renewed volcanism began in the oceanic forearc at 25 Ma producing boninitic-like, SSZ and within-plate alkalic and calc-alkaline rocks. Rocks of these types temporally overlap ophiolite emplacement and subsequent Miocene continental arc construction. © 2006 Elsevier B.V. All rights reserved.en_HK
dc.languageengen_HK
dc.publisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/epslen_HK
dc.relation.ispartofEarth and Planetary Science Lettersen_HK
dc.rightsEarth and Planetary Science Letters. Copyright © Elsevier BV.en_HK
dc.subjectNorthland arcen_HK
dc.subjectNorthland ophioliteen_HK
dc.subjectSHRIMPen_HK
dc.subjectSouth Fiji Basinen_HK
dc.subjectSSZ lithosphere (SSZL)en_HK
dc.subjectSW Pacificen_HK
dc.titleLink between SSZ ophiolite formation, emplacement and arc inception, Northland, New Zealand: U-Pb SHRIMP constraints; Cenozoic SW Pacific tectonic implicationsen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0012-821X&volume=250&spage=606–632.&epage=&date=2006&atitle=Link+between+SSZ+ophiolite+formation,+emplacement+and+arc+inception,+Northland,+New+Zealand:+U-Pb+SHRIMP+constraints;+Cenozoic+SW+Pacific+tectonic+implications.en_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_fulltext-
dc.identifier.doi10.1016/j.epsl.2006.07.047en_HK
dc.identifier.scopuseid_2-s2.0-33749444132en_HK
dc.identifier.hkuros133642en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-33749444132&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume250en_HK
dc.identifier.issue3-4en_HK
dc.identifier.spage606en_HK
dc.identifier.epage632en_HK
dc.identifier.isiWOS:000242195100015-
dc.publisher.placeNetherlandsen_HK
dc.identifier.scopusauthoridWhattam, SA=8264574200en_HK
dc.identifier.scopusauthoridMalpas, J=7006136845en_HK
dc.identifier.scopusauthoridSmith, IEM=7404425799en_HK
dc.identifier.scopusauthoridAli, JR=7102266465en_HK

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