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dc.contributor.authorCooke, Penelope J.en_US
dc.contributor.authorNelson, Campbell S.en_US
dc.contributor.authorCrundwell, Martin P.en_US
dc.contributor.authorField, Brad D.en_US
dc.contributor.authorElkington, E. Shirleyen_US
dc.contributor.authorStone, Harold H.en_US
dc.date.accessioned2008-03-19T05:08:16Z
dc.date.available2007-04-23en_US
dc.date.available2008-03-19T05:08:16Z
dc.date.issued2004-12-01en_US
dc.identifier.citationCooke, P. J., Nelson, C. S., Crundwell, M. P., Field, B. D., Elkington, E. S., & Stone, H. H. (2004). Textural variations in Neogene pelagic carbonate ooze at DSDP Site 593, southern Tasman Sea, and their paleoceanographic implications. New Zealand Journal of Geology & Geophysics. 47(4), 787-807.en_US
dc.identifier.urihttps://hdl.handle.net/10289/182
dc.description.abstractChanges in Neogene sediment texture in pelagic carbonate-rich oozes on the Challenger Plateau, southern Tasman Sea, are used to infer changes in depositional paleocurrent velocities. The most obvious record of textural change is in the mud:sand ratio. Increases in the sand content are inferred to indicate a general up-core trend towards increasing winnowing of sediments resulting from increasing flow velocity of Southern Component Intermediate Water (SCIW), the forerunner of Antarctic Intermediate Water. In particular, the intervals c. 19-14.5 Ma, c. 9.5-8 Ma, and after 5 Ma are suggested to be times of increased SCIW velocity and strong sediment winnowing. Within the mud fraction, the fine silt to coarse clay sizes from 15.6 to 2 µm make the greatest contribution to the sediments and are composed of nannofossil plates. During extreme winnowing events it is the fine silt to very coarse clay material (13-3 µm) within this range that is preferentially removed, suggesting the 10 µm cohesive silt boundary reported for siliciclastic sediments does not apply to calcitic skeletal grains. The winnowed sediment comprises coccolithophore placoliths and spheres, represented by a mode at 4-7 µm. Further support for seafloor winnowing is gained from the presence in Hole 593 of a condensed sedimentary section from c. 18 to 14 Ma where the sand content increases to c. 20% of the bulk sample. Associated with the condensed section is a 6 m thick orange unit representing sediments subjected to particularly oxygen-rich, late early to early middle Miocene SCIW. Together these are inferred to indicate increased SCIW velocity resulting in winnowed sediment associated with faster arrival of oxygen-rich surface water subducted to form SCIW. Glacial development of Antarctica has been recorded from many deep-sea sites, with extreme glacials providing the mechanism to increase watermass flow. Miocene glacial zones Mi1b-Mi6 are identified in an associated oxygen isotope record from Hole 593, and correspond with times of particularly invigorated paleocirculation, bottom winnowing, and sediment textural changes.en_US
dc.format.mimetypeapplication/pdf
dc.language.isoen
dc.publisherSIR Publishingen_NZ
dc.relation.urihttp://www.rsnz.org/publish/nzjgg/2004/056.phpen_US
dc.rightsThe final, definitive version of this article has been published in the Journal, New Zealand Journal of Geology & Geophysics, 47(4), (2004), (c) Royal Society of New Zealand at the Royal Society of New Zealand Journals Online webpage.en_US
dc.subjectTasman Seaen_US
dc.subjectcarbonateen_US
dc.subjecttextureen_US
dc.subjectNeogeneen_US
dc.subjectDSDP Site 593en_US
dc.subjectwinnowingen_US
dc.titleTextural variations in Neogene pelagic carbonate ooze at DSDP Site 593, southern Tasman Sea, and their paleoceanographic implicationsen_US
dc.typeJournal Articleen_US
dc.identifier.doi10.1080/00288306.2004.9515089en_NZ
dc.relation.isPartOfNew Zealand Journal of Geology and Geophysicsen_NZ
pubs.begin-page787en_NZ
pubs.elements-id30420
pubs.end-page807en_NZ
pubs.issue4en_NZ
pubs.volume47en_NZ


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