Depositional Processes on the continental slope of Ross Sea (Antarctica) during the Cenozoic in relation with the ice sheet and sub bottom currents dynamics

• Main Author: Olivo Elisabetta
• Other Authors: Olivo, Elisabetta, DE SANTIS, LAURA
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Università degli Studi di Siena 2019
• Subjects: Antarctica; slope processes; Ross Sea; ice sheet; currents dynamics; Settore GEO/11 - Geofisica Applicata; Settore GEO/02 - Geologia Stratigrafica e Sedimentologica; Antarctic; West Antarctic Ice Sheet; East Antarctic Ice Sheet; Antarc*; Ice Sheet; National Antarctic Research Program; Sea ice
• Online Access: http://hdl.handle.net/11365/1078234

The southeastern Ross Sea outer shelf and slope are key areas to study the interactions between oceanic and glacial dynamics on a high latitude continental margin. I present a multidisciplinary study with the integration of geological, geophysical and oceanographic dataset, derived from the seismic database SDLS (Antarctic Seismic Data Library System), as well as from new acquisitions, in order to reconstruct the slope and rise processes of the Eastern Ross Sea and to propose a depositional model of the margin evolution. As part of the PNRA (National Antarctic Research Program) - WHISPERS project, during the XII Antarctic expedition of the research vessel OGS Explora (January-March 2017) new data were acquired and subsequently interpreted for this thesis: multibeam bathymetric profiles, single-channel seismic profiles, sub-bottom chirp profiles, XBT (Expandable Bathy-Thermograph) data and ADCP (Acoustic Doppler Current Profiler) data, on the easternmost edge of the Ross Sea (generally covered by sea ice). During the Cenozoic, the continental slope of the Eastern Ross Sea was affected by several changes, caused by erosion and deposition made by glaciers (ice streams) and bottom currents, in response to sea level and climate changes. The main facies, discordances and sequences in the entire study area, allow recognizing three important phases of evolution of the continental margin: • Pre-Miocene - Lower Miocene: the study area is influenced by glaciers and ice streams coming from west-south-west, presumably connected to the EAIS (East Antarctic Ice Sheet) dynamics; • Middle-Upper Miocene: in the study area there is a transition to a greater contribution of glaciers coming from the south, presumably connected to the WAIS (West Antarctic Ice Sheet) dynamic; • Lower Pliocene - current time: the sediment deposition by ice streams becomes more confined, the over deepening of the continental shelf and the construction of trough-mouth fans mark a transition to a colder regime. The most investigated area covers the outer ...