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dc.contributor.authorNelson, Campbell S.en_US
dc.contributor.authorCooke, Penelope J.en_US
dc.date.accessioned2008-03-19T05:11:35Z
dc.date.available2007-04-19en_US
dc.date.available2008-03-19T05:11:35Z
dc.date.issued2001-12-01en_US
dc.identifier.citationNelson, C.S., & Cooke, P. J. (2001). History of oceanic front development in the New Zealand sector of the Southern Ocean during the Cenozoic--a synthesis. New Zealand Journal of Geology & Geophysics. 44(4), 535-553.en_US
dc.identifier.urihttps://hdl.handle.net/10289/193
dc.description.abstractThe New Zealand sector of the Southern Ocean (NZSSO) has opened about the Indian-Pacific spreading ridge throughout the Cenozoic. Today the NZSSO is characterised by broad zonal belts of antarctic (cold), subantarctic (cool), and subtropical (warm) surface-water masses separated by prominent oceanic fronts: the Subtropical Front (STF) c. 43deg.S, Subantarctic Front (SAF) c. 50deg.S, and Antarctic Polar Front (AAPF) c. 60deg.S. Despite a meagre database, the broad pattern of Cenozoic evolution of these fronts is reviewed from the results of Deep Sea Drilling Project-based studies of sediment facies, microfossil assemblages and diversity, and stable isotope records, as well as from evidence in onland New Zealand Cenozoic sequences. Results are depicted schematically on seven paleogeographic maps covering the NZSSO at 10 m.y. intervals through the Cenozoic. During the Paleocene and most of the Eocene (65-35 Ma), the entire NZSSO was under the influence of warm to cool subtropical waters, with no detectable oceanic fronts. In the latest Eocene (c. 35 Ma), a proto-STF is shown separating subantarctic and subtropical waters offshore from Antarctica, near 65deg.S paleolatitude. During the earliest Oligocene, this front was displaced northwards by development of an AAPF following major global cooling and biotic turnover associated with ice sheet expansion to sea level on East Antarctica. Early Oligocene full opening (c. 31 Ma) of the Tasmanian gateway initiated vigorous proto-circum-Antarctic flow of cold/cool waters, possibly through a West Antarctic seaway linking the southern Pacific and Atlantic Oceans, including detached northwards "jetting" onto the New Zealand plateau where condensation and unconformity development was widespread in cool-water carbonate facies. Since this time, a broad tripartite division of antarctic, subantarctic, and subtropical waters has existed in the NZSSO, including possible development of a proto-SAF within the subantarctic belt. In the Early-early Middle Miocene (25-15 Ma), warm subtropical waters expanded southwards into the northern NZSSO, possibly associated with reduced ice volume on East Antarctica but particularly with restriction of the Indonesian gateway and redirection of intensified warm surface flows southwards into the Tasman Sea, as well as complete opening of the Drake gateway by 23 Ma allowing more complete decoupling of cool circum-Antarctic flow from the subtropical waters. During the late Middle-Late Miocene (15-5 Ma), both the STF and SAF proper were established in their present relative positions across and about the Campbell Plateau, respectively, accompanying renewed ice buildup on East Antarctica and formation of a permanent ice sheet on West Antarctica, as well as generally more expansive and intensified circum-Antarctic flow. The ultimate control on the history of oceanic front development in the NZSSO has been plate tectonics through its influence on the paleogeographic changes of the Australian-New Zealand-Antarctic continents and their intervening oceanic basins, the timing of opening and closing of critical seaways, the potential for submarine ridges and plateaus to exert some bathymetric control on the location of fronts, and the evolving ice budget on the Antarctic continent. The broad trends of the Cenozoic climate curve for New Zealand deduced from fossil evidence in the uplifted marine sedimentary record correspond well to the principal paleoceanographic events controlling the evolution and migration of the oceanic fronts in the NZSSO.en_US
dc.format.mimetypeapplication/pdf
dc.language.isoen
dc.publisherSIR Publishingen_NZ
dc.relation.urihttp://www.royalsociety.org.nz/publications/journals/nzjg/en_US
dc.rightsThe final, definitive version of this article has been published in the Journal, New Zealand Journal of Geology & Geophysics, 44(4), (2001), (c) Royal Society of New Zealand at the Royal Society of New Zealand Journals Online webpage.en_US
dc.subjectNew Zealanden_US
dc.subjectSouthwest Pacificen_US
dc.subjectAntarcticaen_US
dc.subjectSouthern Oceanen_US
dc.subjectCenozoicen_US
dc.subjectpaleoclimateen_US
dc.subjectpaleoceanographyen_US
dc.subjectoceanic frontsen_US
dc.subjectDSDP coresen_US
dc.subjectice sheetsen_US
dc.titleHistory of oceanic front development in the New Zealand sector of the Southern Ocean during the Cenozoic--a synthesisen_US
dc.typeJournal Articleen_US
dc.relation.isPartOfNew Zealand Journal of Geology and Geophysicsen_NZ
pubs.begin-page537en_NZ
pubs.elements-id27164
pubs.end-page555en_NZ
pubs.volume44en_NZ


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