Antiphase dynamics between cold-based glaciers in the Dry Valleys region and ice extent in the Ross Sea, Antarctica during MIS 5

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dc.contributor.authorAnderson, JTHen_AU
dc.contributor.authorFink, Den_AU
dc.contributor.authorFujioka, Ten_AU
dc.contributor.authorWilson, GSen_AU
dc.contributor.authorWilcken, KMen_AU
dc.contributor.authorAbramov, Aen_AU
dc.contributor.authorDemidov, Nen_AU
dc.date.accessioned2023-01-19T04:56:26Zen_AU
dc.date.available2023-01-19T04:56:26Zen_AU
dc.date.issued2021-11-17en_AU
dc.date.statistics2022-05-27en_AU
dc.description.abstractDuring interglacial conditions in Marine Isotope Stage (MIS) 5, outlet and alpine glaciers in the Dry Valleys region, Antarctica, appear to have advanced in response to increased open ocean in the Ross Sea. However, the timing and extent of antiphase behaviour between these glaciers and ice in the Ross Sea is poorly resolved. Here, we report the antiphase behaviour through retreat of a peripheral lobe of Taylor Glacier in Pearse Valley, an area that was glaciated during MIS 5. First, we measured cosmogenic ¹⁰ Be and ²⁶ Al in 3 granite cobbles from thin, patchy drift (Taylor 2 Drift) in Pearse Valley to constrain the timing of retreat of Taylor Glacier. Assuming simple continuous exposure, our exposure ages suggest Taylor Glacier had partially retreated from Pearse Valley no later than 71 ka. Timing of retreat after 71 ka, until the Last Glacial Maximum (LGM), when Taylor Glacier was at a minimum position, remains unresolved. Second, we measured paired ¹⁰ Be and ²⁶ Al depth profiles to ~3 metres in permafrost in proximity to the cobble sampling sites at Pearse Valley and neighbouring Lower Wright Valley. The ¹⁰ Be and ²⁶ Al depth profiles from both sites show no clear exponential attenuation trend which suggest that both deposits are too young for the most recent exposure (≥71 ka for Pearse Valley and LGM – early Holocene for Lower Wright Valley) to alter the profile, and measured nuclide concentrations are essentially dominated by inheritance. Using ¹⁰ Be depth profile data from Pearse Valley we calculate a maximum age of ~100 ka for surface layer permafrost formation. The cobble exposure-ages and depth profile constrain surface permafrost formation in Pearse Valley to between ~71 – 102 ka, following the retreat of the Taylor Glacier from Pearse Valley. These new data are consistent with geochronology from central Taylor Valley, and suggest changes in moisture delivery over Taylor Dome during MIS 5c and 5a appear to be associated with the extent of the Ross Ice Shelf and sea ice in the Ross Sea. Our ²⁶ Al/¹⁰ Be concentration ratios for all depth profile samples also exhibit relatively constant and suppressed ratios of 4.3 and 5.2 for Pearse and Wright valleys, respectively, indicating that prior to surface permafrost formation, these sediments experienced a significant complex prior exposure history. Assuming a simple burial scenario, the observed ²⁶ Al/¹⁰ Be ratios are equivalent to a total exposure-burial history of ~1.2 Ma, somewhat consistent with the Packard dune field in Victoria Valley. Our new data corroborate antiphase behaviour between outlet and alpine glaciers in the Dry Valleys region and ice extent in the Ross Sea, and imply a causal mechanism with cold-based glacier advance and retreat being controlled by moisture availability and drying, respectively due to ice retreat and expansion in the Ross Sea. © The Authorsen_AU
dc.identifier.citationAnderson, J., Fink, D., Fuijoka, T., Wilson, G., Wilcken, K., Abramov, A., & Demodov. N. (2021). Antiphase dynamics between cold-based glaciers in the Dry Valleys region and ice extent in the Ross Sea, Antarctica during MIS 5. Paper presented to the 15th International Conference on Accelerator Mass Spectrometry. ANSTO Sydney, Australia. November 15th – 19th. (pp. 31). Retrieved from: https://ams15sydney.com/wp-content/uploads/2021/11/AMS-15-Full-Program-and-Abstract-Book-R-1.pdfen_AU
dc.identifier.conferenceenddate19 November 2021en_AU
dc.identifier.conferencename15th International Conference on Accelerator Mass Spectrometryen_AU
dc.identifier.conferenceplaceSydney, Australiaen_AU
dc.identifier.conferencestartdate15 November 2021en_AU
dc.identifier.pagination31en_AU
dc.identifier.urihttps://ams15sydney.com/wp-content/uploads/2021/11/AMS-15-Full-Program-and-Abstract-Book-R-1.pdfen_AU
dc.identifier.urihttps://apo.ansto.gov.au/dspace/handle/10238/14407en_AU
dc.language.isoenen_AU
dc.publisherAustralian Nuclear Science and Technology Organisationen_AU
dc.subjectAntarcticaen_AU
dc.subjectSeasen_AU
dc.subjectValleysen_AU
dc.subjectGlaciersen_AU
dc.subjectIceen_AU
dc.subjectQuaternary perioden_AU
dc.subjectGeochronologyen_AU
dc.subjectMoistureen_AU
dc.titleAntiphase dynamics between cold-based glaciers in the Dry Valleys region and ice extent in the Ross Sea, Antarctica during MIS 5en_AU
dc.typeConference Abstracten_AU
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