Oceanographic and climatic influences on Trooz Glacier and Collins Bay, Antarctic Peninsula, during the Holocene

• Main Author: Fonseca, Adlai Nathanael Reuel
• Other Authors: Totten Minzoni, Rebecca, Andrus, C. Fred, Tobin, Thomas, Wellner, Julia Smith
• Format: Thesis
• Language: English
• Published: University of Alabama Libraries 2019
• Subjects: Geology; Paleoclimate science; Marine geology; Antarctic; Antarctic Peninsula; Collins Bay; Graham Land; Open Bay; The Antarctic; Trooz; Trooz Glacier; Antarc*; Antarctica; Ice Shelf; Ice Shelves
• Online Access: http://ir.ua.edu/handle/123456789/6498

Electronic Thesis or Dissertation The Antarctic Peninsula (AP) has dramatically warmed with the majority of its outlet glaciers receeding since the 1970’s. Relatively warm Circumpolar Deepwater (CDW) that undermelts ice shelves is prevalent on the western AP shelf, and raises questions of the relative influence of atmospheric vs. oceanographic forcings on modern ice stability. It is imperative to extend the limited satellite and instrumental record of glacier change with long paleo-records of glacial response to past climate and oceanographic changes during the Holocene to evaluate the significance of the recently observed glacial recession in the AP. I interrogate sediment cores KC41 and JPC51, collected during the 2007 RV/IB N.B. Palmer cruise to Collins Bay, a small, open bay that drains Trooz Glacier on the Graham Land coast of the western AP. Radiocarbon ages throughout the ~14 meter sediment record provide a timeline of Trooz Glacier behavior and environmental change over the Holocene. Variations in diatom assemblage and abundance, analysis of total organic carbon (TOC), nitrogen, δ15N, δ13C, grain size, and magnetic susceptibility are used to interpret glacial marine environments at sub-centennial scales. The multi-proxy core analysis indicates a minimum age of glacial retreat from Collins Bay ~9.3 cal. kyr. B.P. Diatom abundance, Eucampia antarctica abundance, Chaetoceros Resting Spores (CRS) abundance, and TOC indicate productivity increase during glacial recession from ~8.8 to 6.0 cal. kyr. B.P. Absence of ice-rafted debris, low TOC and diatom productivity proxies from ~6.0 to 5.4 cal. kyr. B.P. indicate potential sub-ice shelf conditions followed by a melt out during a warming period. A subsequent increase in productivity and Thalassiosira antarctica-dominated assemblages with the prominent presence of Fragilariopsis kerguelensis indicate open marine conditions from ~5.4 to 0.7 cal. kyr. B.P., and incursion of CDW into the open bay. A decrease in TOC, nitrogen, CRS, and grain size indicate the ...