The Hillary Canyon and the Iselin Bank (eastern Ross Sea, Antarctica); alongslope and downslope route for Ross Sea bottom water

Author(s): De Santis, L.; Bergamasco, A.; Colizza, E.; Geletti, R.; Accaino, F.; Wardell, N.; Olivo, E.; Petronio, L.; Henrys, S. A.; Black, J.; McKay, Robert M.; Bohm, G.
Author Affiliation(s): Primary:
Istituto Nazionale Oceanografia, Sgonico, Italy
Other:
National Institute of Oceanography and Applied Geophysics OGS, Geophysics, Trieste, Italy
Consiglio Nazionale delle Ricerche, Institute of Marine Sciences, Bologna, Italy
University of Trieste, Mathematics and Geosciences, Trieste, Italy
GNS Science, Lower Hutt, New Zealand
Victoria University of Wellington, Wellington, New Zealand
Volume Title: AGU 2015 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2015; American Geophysical Union 2015 fall meeting, San Francisco, CA, Dec. 14-18, 2015. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: The modern seabed of the Antarctic continental slope generally does not show a rugged geomorphology. Channel systems incise the lower continental rise, but in most cases they are inherited features formed as channel-levee turbiditic systems during past, more temperate times. The Hillary Canyon cuts the eastern Ross Sea continental slope and rise, to the Southeast of the Iselin Bank, and is directly connected to the Glomar Challenger Trough on the continental shelf. Cold dense salty water forms today in the Ross Sea polynya, spreads below the Ross Ice Shelf, becomes supercooled, fills up the landward deepening Glomar Challenger Trough and then spills over the sill of the shelf edge and flows downslope, often along the Hillary Canyon, in a geostrophic way, deviated westwards by the Coriolis Force, but sometimes also with a cascading a-geostrophic behaviour. This supercold water signal was found on the continental slope down to 1200 m depth. The shape of this tongue of modified ISW, whose thickness reaches up to 100 m, is very narrow, suggesting that the overflow occurs in very localized areas along the slope. Here we combine seismic stratigraphy analysis of multichannel seismic reflection profiles, box and gravity cores in the Hillary Canyon and along the eastern flank of the Iselin Bank, with seabed bathymetry and numerical modelling of the vertical and spatial distribution of the water masses, in order to identify modern and past pathways of the Ross Sea Bottom Water current. The results of this work show that the Hillary Canyon and the sediment mounds that formed along its flanks have been active since early Miocene times. Sediment drift-moat features and sediment waves are indicative of strong Northwest bottom currents reworking the seabed sediments at different water depths along the slope, possibly since the late Miocene. These sediment drifts are some of the targets of the IODP proposal 751-full.
Year of Publication: 2015
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 07 Marine Geology and Oceanography; Cores; Integrated Ocean Drilling Program; Marine sediments; Research; Sediments
Record ID: 2016075316
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data supplied by, and/or abstract, Copyright, American Geophysical Union, Washington, DC, United States

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