Insights into Late Holocene Climate of the Ross Sea Region, Antarctica, from High Resolution Ice Core Chemistry

The Ross Sea is the most biologically productive sector of the Southern Ocean and a region of substantial bottom water formation. Modulation of these processes has the potential to influence both regional and global climate. Analysis of snow pit and ice core samples from Mt Erebus Saddle (MES) on Ro...

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Bibliographic Details
Main Author: Rachael Rhodes
Format: Thesis
Language:unknown
Published: 2011
Subjects:
Glaciology
Ice core
Antarctica
Geochemistry
049999 Earth Sciences not elsewhere classified
Degree Name: Doctor of Philosophy
Degree Level: Doctoral
Degree Discipline: Geology
School: School of Geography
Environment and Earth Sciences
Ross Island
Ross Sea
Southern Ocean
Antarc*
ice core
Sea ice
Online Access:https://doi.org/10.26686/wgtn.19252406
https://figshare.com/articles/thesis/Insights_into_Late_Holocene_Climate_of_the_Ross_Sea_Region_Antarctica_from_High_Resolution_Ice_Core_Chemistry/19252406
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Summary:The Ross Sea is the most biologically productive sector of the Southern Ocean and a region of substantial bottom water formation. Modulation of these processes has the potential to influence both regional and global climate. Analysis of snow pit and ice core samples from Mt Erebus Saddle (MES) on Ross Island allows reconstruction of Late Holocene climate of this key region of Antarctica. The biogenic sulphur species, methylsulphonate (MS-), is shown to be a quantitative proxy for Ross Sea Polynya conditions. MS- concentrations of the snow pit, dating from 1999-2005 AD, strongly correlate (R2 > 0.9) with interannual changes in open water area and surface ocean primary productivity caused by the sea-ice-damming effect of large icebergs. Trace element analysis of ice core samples allows delineation between: 1) terrestrial and marine sources, 2) anthropogenic Pb pollution, and 3) volcanic trace element deposition. To assess the contribution of mineral dust leaching to trace element concentrations, powdered rock standards were leached in 1 wt.% HNO3 and periodically sampled for analysis. Results demonstrate that trace element leaching in acidified samples is time- and mineral-dependent. Incongruent leaching of trace elements from dust causes errors in crustal enrichment factors and produces trace element ratios, which do not reflect dust provenance.

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