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

• 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

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.