Defining past volume of grounded ice in the Ross Sea

Simple item page
dc.contributor.authorLilly, Ken_AU
dc.contributor.authorWilson, GSen_AU
dc.contributor.authorFink, Den_AU
dc.contributor.authorLevy, Ren_AU
dc.contributor.authorMifsud, Cen_AU
dc.date.accessioned2010-10-25T22:57:32Zen_AU
dc.date.available2010-10-25T22:57:32Zen_AU
dc.date.issued2009-11-26en_AU
dc.date.statistics2009-11-26en_AU
dc.description.abstractA large portion of global sea-level increase over the last glacial cycle is believed to originate from reduction in the volume of West Antarctic ice including ice grounded across the Ross Sea. The evidence for this comes from observation of glacigene sediments in the Ross Embayment, both onshore and offshore, indicating a much greater ice extent in the past. However, much of this evidence is not dated directly. Marine geophysical surveys show that the Antarctic Ice Sheet did in many locations ground out to the continental shelf edge, but it is not clear whether this happened at the Last Glacial Maximum. On land, our understanding of former ice extent in the Ross Sea region comes primarily from a glacial sedimentary deposit known as the Ross Sea Drift. The limit of these sediments has been used to define the volume of grounded ice in the Ross Sea and by further inference in the adjacent West Antarctic, representing an ice volume of some 9 million km3, or 14 m sea level equivalent. However, the Ross Sea Drift is defined by common processes and facies rather than as a time restricted unit and conflicting interpretations from different locations suggest different timing and different ice configurations. The geographic area of the southern McMurdo Ice Shelf (between Black Island, Minna Bluff and Mount Discovery) is identified as a location where the reconstructions are in greatest conflict. We present new constraints on the age of formation of these moraines from the application of cosmogenic exposure dating on 16 sandstone erratics collected from moraines on the flanks of Minna Bluff and Mount Discovery. These ice shelf marginal moraines have traditionally been included in the Ross Sea Drift. The sandstone erratics themselves are ideal targets for exposure dating as they include large blocks (> 1 m) that sit proud of the surrounding drift, they are quartz rich and are from an Eocene formation for which there is no known outcrop. While the origin of the erratics is not confirmed, each of the available reconstructions infers them to have been exhumed by advancing ice grounded in the Ross Sea. Thus we can assume that their exposure age relates to glacial erosion and deposition.en_AU
dc.identifier.booktitleJoint Geological and Geophysical Societies Conference 2009: Programme & Abstracten_AU
dc.identifier.citationLilly, K., Wilson, G. S., Fink, D., Levy, R., & Mifsud, C. (2009). Defining past volume of grounded ice in the Ross Sea. Presentation to the Joint Geological and Geophysical Societies Conference, 23rd – 27th November 2009. In Joint Geological and Geophysical Societies Conference 2009: Programme & Abstracts, Geological Society of New Zealand Miscellaneous Publication 128A (pp. 122). Oamaru, New Zealand: Oamaru Opera House.en_AU
dc.identifier.conferenceenddate27 November 2011en_AU
dc.identifier.conferencenameJoint Geological and Geophysical Societies Conferenceen_AU
dc.identifier.conferenceplaceOmaru, New Zealanden_AU
dc.identifier.conferencestartdate23 November 2007en_AU
dc.identifier.govdoc2941en_AU
dc.identifier.isbn9781877480072en_AU
dc.identifier.pagination122en_AU
dc.identifier.placeofpublicationOamaru, New Zealanden_AU
dc.identifier.urihttp://apo.ansto.gov.au/dspace/handle/10238/2761en_AU
dc.language.isoenen_AU
dc.publisherGeological Society of New Zealanden_AU
dc.subjectSea levelen_AU
dc.subjectAntarcticaen_AU
dc.subjectSedimentsen_AU
dc.subjectGlaciersen_AU
dc.subjectAge estimationen_AU
dc.subjectMorainesen_AU
dc.titleDefining past volume of grounded ice in the Ross Seaen_AU
dc.typeConference Presentationen_AU
Files
License bundle
Now showing 1 - 2 of 2
Thumbnail Image
Name:
license.txt
Size:
1.71 KB
Format:
Item-specific license agreed upon to submission
Description:
Download
Thumbnail Image
Name:
MP128A_2009_GSNZ_conference_Oamaru_abstract_volume.pdf
Size:
2.3 MB
Format:
Adobe Portable Document Format
Description:
Download
Collections
Conference Publications