Mid-holocene variability in the marine C-14 reservoir age for northern coastal Papua New Guinea

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dc.contributor.authorMcGregor, HVen_AU
dc.contributor.authorGagan, MKen_AU
dc.contributor.authorMcCulloch, MTen_AU
dc.contributor.authorHodge, Een_AU
dc.contributor.authorMortimer, GEen_AU
dc.date.accessioned2009-01-28T01:11:51Zen_AU
dc.date.accessioned2010-04-30T05:06:31Zen_AU
dc.date.available2009-01-28T01:11:51Zen_AU
dc.date.available2010-04-30T05:06:31Zen_AU
dc.date.issued2008-08en_AU
dc.date.statistics2008-08en_AU
dc.description.abstractChanges in oceanic radiocarbon (C-14) reservoir ages through the deglaciation and Holocene can provide important information on ocean circulation as Earth's climate warmed. Here, we present reservoir ages for the western tropical Pacific that span the mid-Holocene transition from less to more frequent El Nino events. Reservoir ages were calculated using paired U-Th and conventional C-14 dating of eight individual fossil coral samples from Koil and Muschu Islands, northern coastal Papua New Guinea (PNG). AMS C-14 and MC-ICPMS U-Th dating of additional samples from six of the fossil corals were used to confirm the TIMS U-Th and conventional C-14 ages. The combined results show average reservoir ages of 185 +/- 30 C-14 yr (n = 4) for 7220-5850 yr BP compared to 420 C-14 yr for a modern coral from Muschu Island. From 5850 to 5420 yr BP reservoir ages increase to modern values. The relatively young reservoir ages from 7220 to 5850 yr BP are best explained by greater influx of well-equilibrated sub-tropical water from the southern branch of the South Equatorial Current (SEC). This is consistent with strengthening trade winds (facilitating air-sea exchange) and a more northerly position of the Intertropical Convergence Zone thought to have occurred at this time. The transition to more modern-like reservoir ages from 5850 to 5420 yr BP suggests modern oceanic circulation patterns were established during this interval. The onset of modern El Nino activity around this time would have served to enhance the intrusion of C-14-depleted equatorial waters via the south equatorial branch of the SEC. Overall, the changes in reservoir age presented here for the western tropical Pacific suggest that Holocene changes in the El Nino-Southern Oscillation state of the tropical Pacific resulted in reorganisation of oceanic circulation in this region. © 2008, Elsevier Ltd.en_AU
dc.identifier.citationMcGregor, H. V., Gagan, M. K., McCulloch, M. T., Hodge, E., & Mortimer, G. (2008). Mid-holocene variability in the marine C-14 reservoir age for northern coastal Papua New Guinea. Quaternary Geochronology, 3(3), 213-225. doi:10.1016/j.quageo.2007.11.002en_AU
dc.identifier.govdoc1418en_AU
dc.identifier.issn1871-1014en_AU
dc.identifier.issue3en_AU
dc.identifier.journaltitleQuaternary Geochronologyen_AU
dc.identifier.pagination213-225en_AU
dc.identifier.urihttp://dx.doi.org/doi:10.1016/j.quageo.2007.11.002en_AU
dc.identifier.urihttp://apo.ansto.gov.au/dspace/handle/10238/1257en_AU
dc.identifier.volume3en_AU
dc.language.isoenen_AU
dc.publisherElsevieren_AU
dc.subjectQuaternary perioden_AU
dc.subjectWater reservoirsen_AU
dc.subjectPapua New Guineaen_AU
dc.subjectCarbon 14en_AU
dc.subjectSouthern Oscillationen_AU
dc.subjectIsotope datingen_AU
dc.titleMid-holocene variability in the marine C-14 reservoir age for northern coastal Papua New Guineaen_AU
dc.typeJournal Articleen_AU
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