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Variability in the uranium isotopic composition of the oceans over glacial-interglacial timescales

Esat, Tezer; Yokoyama, Yusuke

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Uranium-series mass spectrometric analyses of corals from the uplifted last glacial terraces at Huon Peninsula, Papua New Guinea, that grew from 50,000 years ago to 30,000 years ago show systematically low values of 234U/238U, at the time of coral growth, compared with modern corals. When combined with coral data from other studies a systematic trend emerges indicating shifts in the 234U/238U ratio at times of major glacial-interglacial transitions that involve large variations in sea-levels....[Show more]

dc.contributor.authorEsat, Tezer
dc.contributor.authorYokoyama, Yusuke
dc.date.accessioned2015-12-07T22:13:44Z
dc.identifier.issn1872-9533
dc.identifier.urihttp://hdl.handle.net/1885/17133
dc.description.abstractUranium-series mass spectrometric analyses of corals from the uplifted last glacial terraces at Huon Peninsula, Papua New Guinea, that grew from 50,000 years ago to 30,000 years ago show systematically low values of 234U/238U, at the time of coral growth, compared with modern corals. When combined with coral data from other studies a systematic trend emerges indicating shifts in the 234U/238U ratio at times of major glacial-interglacial transitions that involve large variations in sea-levels. From last glacial to Holocene, the rate of change in δ234U is approximately 1‰ per thousand years. The variations in the U budget of the oceans appear to be due to accumulation of excess 234U in near shore areas in anoxic and suboxic sediments, in salt marshes and mangroves, in estuaries, and in continental margins during periods of warm climate and high sea-levels. These near-shore areas are exposed during periods of low sea level resulting in rapid oxidation of U into highly soluble phases. The subsequent release of 234U-enriched uranium into the oceans occurs over a sustained period, in step with rising sea-levels.
dc.publisherPergamon-Elsevier Ltd
dc.sourceGeochimica et Cosmochimica Acta
dc.subjectKeywords: glacial-interglacial cycle; isotopic composition; Last Glacial; paleoceanography; uranium isotope; Anthozoa; Rhizophoraceae
dc.titleVariability in the uranium isotopic composition of the oceans over glacial-interglacial timescales
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume70
dc.date.issued2006
local.identifier.absfor040605 - Palaeoclimatology
local.identifier.absfor040203 - Isotope Geochemistry
local.identifier.ariespublicationu3533991xPUB1
local.type.statusPublished Version
local.contributor.affiliationEsat, Tezer, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationYokoyama, Yusuke, University of Tokyo
local.description.embargo2037-12-31
local.bibliographicCitation.startpage4140
local.bibliographicCitation.lastpage4150
local.identifier.doi10.1016/j.gca.2006.06.013
dc.date.updated2015-12-07T07:18:56Z
local.identifier.scopusID2-s2.0-33746804153
CollectionsANU Research Publications

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