Reconstruction of Marine Isotope Stages 12/14 Paleoceanography in Western Central Arctic Sediments
Abstract
A paleoceanographic reconstruction of MIS12/14 (Unit F) for the western Arctic Ocean was made using lithologic data from 196 cores collected from T-3 Ice Island and during the HOTRAX and other expeditions. Sediment isopleths indicate a pronounced Beaufort Gyre-type sediment distribution existed during this period with the sea/glacial ice being transported out of the Western Arctic through a zone located on the southern end of the Lomonosov Ridge. Within this outfall zone up to 50+ cm of sediment was deposited within a linear 120 km wide region. Due to the occurrence of these deposits, the migration of sea/glacial ice appears to have been compressed into the outfall zone potentially by a northern boundary of ice moving in the Transpolar Drift as well as ice from other source areas. Elemental analyses from 14 cores indicate the sediment in Unit F has a very distinct and consistent geochemistry across the Northwind Ridge, Alpha and Mendeleev Ridges as well as into the linear outfall zone. However, this pattern is less obvious within the Ellesmere Island Shelf area which may reflect the influx of sediment from adjacent glaciated areas. Cluster Analyses of size data from 91 Malvern analyzes of Unit F indicates a strong similarity of size distributions across the western Arctic in the unit where the dominant modal distribution is in the fine sortable silt range. An exception to this exists at the beginning of the Unit F where a distinct sand mode exists (i.e. >100 μm). Evaluation of IRD from four cores located across the study area indicate the occurrence of clastics, quartz, and crystalline rock fragments existing up to the beginning of Unit F, with the proportion of clastics is depressed during the glacial event. Except near Ellesmere Island, the similarity of the sediments geochemistry and size data suggests at least two different modes of sediment input was occurring, that associated with coarser sediment input from sea/glacial ice and a below ice influx/redistribution of finer grained sediment (potentially turbidite/nepholoid-type transport) that generated a more regional geochemical signature. However, prior to the beginning of Unit F, the influx of clastic IRD suggests a transport of previously eroded sediment or clastic rich strata from sources such as Canadian or Siberian Shelf that differ from the carbonate rich materials that probably is associated with adjacent Canadian source regions.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFMPP33A1900M
- Keywords:
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- 3022 MARINE GEOLOGY AND GEOPHYSICS / Marine sediments: processes and transport;
- 4207 OCEANOGRAPHY: GENERAL / Arctic and Antarctic oceanography;
- 4926 PALEOCEANOGRAPHY / Glacial