Low latitude moisture regime changes over the last 14,000 years recorded by diatomaceous sediments from dry tropical Australia.

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dc.contributor.authorWust, RAen_AU
dc.contributor.authorShemesh, Aen_AU
dc.contributor.authorRidd, Pen_AU
dc.contributor.authorStephenson, Jen_AU
dc.contributor.authorJacobsen, GEen_AU
dc.contributor.authorSmith, AMen_AU
dc.date.accessioned2009-12-07T23:54:11Zen_AU
dc.date.accessioned2010-04-30T04:57:49Zen_AU
dc.date.available2009-12-07T23:54:11Zen_AU
dc.date.available2010-04-30T04:57:49Zen_AU
dc.date.issued2007-07en_AU
dc.date.statistics2007-07en_AU
dc.description.abstractA diatomaceous sediment deposit from Long Pocket, NE Queensland, Australia, provides new evidence for rapid climatic changes. Here we present a rare sediment record from the dry tropics that spans the last ~14,000 cal yrs. The 5.5 m thick deposit is composed of purely diatomaceous debris with little atmospheric influx. The site is unique as a basaltic flow isolated and formed the area ~13,600 cal yrs BP. Geochemical data and isotope analysis of the diatoms reveal that primary productivity was high during the onset of the deposit with little changes until the mid Holocene, when abrupt moisture regime changes occurred ~6000 years ago. Oxygen isotope data of the diatoms indicates further that changes in moisture source took place progressively. However, trace elemental data shows that marked changes in atmospheric flux composition occurred ~3800 yrs BP, most likely representing the timing of the onset (strengthening) of the monsoon system. Interestingly, the timing of some of the changes expressed in our record by the geochemical data coincides with Bond-cycles described from the North Atlantic. With our data, we hypothesise that the monsoon system was ineffective for latitudes 17º S during the early Holocene and that moisture was primarily derived from short range trajectories, such as the Coral Sea. Around ~3800 yrs BP abrupt climate changes led to the present system that is dominated by a wet summer monsoon. Our record shows that the dry tropics received more precipitation during the late Pleistocene and early Holocene than during the late Holocene. These findings are similar to findings from the wet tropical NE-Australia. However, our record shows a marked collapse of the ocean/atmospheric system in the low latitudes and possibly an intensification of ENSO during the latter part of the Holocene.en_AU
dc.description.sponsorshipInternational Union for Quaternary Researchen_AU
dc.identifier.citationWust, R. A., Shemesh, A., Ridd, P., Stephenson, J., Jacobsen, G. E., & Smith, A. (2007). Low latitude moisture regime changes over the last 14,000 years recorded by diatomaceous sediments from dry tropical Australia. Presentation to the International Union for Quaternary Research XVII Congress (INQUA) – “The Tropics: Heat Engine of the Quaternary”, 28th July – 3rd August 2007. Cairns, Australia: Cairns Convention Centre. In Quaternary International, 167-168, 456. doi:10.1016/j.quaint.2007.04.001 en_AU
dc.identifier.conferenceenddate3 August 2007en_AU
dc.identifier.conferencenameInternational Union for Quaternary Research XVII Congress (INQUA) – “The Tropics: Heat Engine of the Quaternaryen_AU
dc.identifier.conferenceplaceCairns, Australiaen_AU
dc.identifier.conferencestartdate28 July 2007en_AU
dc.identifier.govdoc1079en_AU
dc.identifier.issn1040-6182en_AU
dc.identifier.journaltitleQuaternary Internationalen_AU
dc.identifier.pagination456en_AU
dc.identifier.urihttp://apo.ansto.gov.au/dspace/handle/10238/2629en_AU
dc.identifier.urihttps://doi.org/https://doi.org/10.1016/j.quaint.2007.04.001en_AU
dc.language.isoenen_AU
dc.publisherElsevieren_AU
dc.subjectAustraliaen_AU
dc.subjectDiatomaceous earthen_AU
dc.subjectSedimentsen_AU
dc.subjectTropical regionsen_AU
dc.subjectDiatomsen_AU
dc.subjectQuaternary perioden_AU
dc.titleLow latitude moisture regime changes over the last 14,000 years recorded by diatomaceous sediments from dry tropical Australia.en_AU
dc.typeConference Abstracten_AU
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