Paleobathymetric Reconstruction, Modeled Ocean Circulation, and Sedimentation History in the Weddell Sea, Antarctica

• Main Author: Huang, Xiaoxia
• Other Authors: Jokat, Wilfried, Gohl, Karsten, Spiegel, Cornelia
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Universität Bremen 2015
• Subjects: paleobathymetric reconstruction; seismic reflection data; ocean circulation; sediment drifts; mass transport deposits; backstripping; 550; 550 Earth sciences and geology; ddc:550; Antarctic; The Antarctic; Weddell Sea; East Antarctic Ice Sheet; Weddell; Ronne Ice Shelf; Antarc*; Antarctica; Antarktis*; Filchner Ronne Ice Shelf; Filchner-Ronne Ice Shelf; Ice Sheet; Ice Shelf
• Online Access: https://media.suub.uni-bremen.de/handle/elib/950; https://nbn-resolving.org/urn:nbn:de:gbv:46-00104853-13

The Weddell Sea basin is of particular significance for understanding climate processes, including the generation of ocean water masses and their influences on ocean circulation as well as the Antarctic ice sheets dynamics. The sedimentary record, preserved in the basin serves as an archive of the pre-glacial to glacial development, ocean circulation and tectonic evolution. This thesis focuses on understanding the sedimentation history and reconstructing paleo-water depths, using all available multichannel seismic lines and existing drilling sites, with the aim to apply the paleo-water depths to General Circulation Models (GCM) of the Weddell Sea basin. A series of sedimentary thicknesses grids (pre-glacial, transitional, full-glacial) and paleobathymetric grids produced in this work are essential contributions for numerical climate simulations and ocean circulations. These sedimentary thickness grids allow the comparison of sedimentary regimes of the pre-glacially dominated and glacially dominated stages of Weddell Sea history. The pre-glacial deposition with thicknesses of up to 5 km was controlled by the tectonic evolution and sea-floor spreading history interacting with terrigenous sediment supply. The transitional unit shows a relatively high sedimentation rate and has thicknesses of up to 3 km, which may be attributed to an early formation of the East Antarctic Ice Sheet having partly advanced to the coast or even inner shelf. The main deposition centre of the full-glacial unit lies in front of the Filchner-Ronne Ice Shelf and has sedimentation rates of up to 140-200 m/Myr, which infers that ice sheets grounded on the middle to outer shelf and that bottom-water currents strongly impacted the deep-sea sedimentation in the middle Miocene. The paleobathymetric grids at 15, 34 and 120 Ma are reconstructed by using a backstripping technique and applied to constrain paleoclimate models. Coupled GCM runs are forced by global warm climatic boundary conditions of the Mid-Miocene and the new Weddell Sea ...