Expanded and integrated seismostratigraphic analysis of the Weddell Sea region, Antarctica


Contact
Karsten.Gohl [ at ] awi.de

Abstract

The Weddell Sea region of the Southern Ocean has a particular significance to ocean circulation, transport of ice masses and global climate variations due to its giant Weddell Sea gyre. This clockwise circulating ocean gyre system is responsible for the exchange and mixing of Antarctic Deep Water with the global circulation as well as the transport of ice masses from the Filchner-Ronne Ice-Shelves of the Antarctic mainland to the Atlantic Ocean. Understanding the development of the Weddell Sea gyre system is linked to the reconstruction of the development of sedimentation and the resulting paleobathymetry. The main objective of this project is to analyze the seismostratigraphic records and to create a digital paleobathymetric map series of the greater Weddell Sea region from pre-glacial times (about 50 Ma) to the present. The data include all existing seismic data and drilling information from the area. Here, we present the construction of a unified stratigraphic model and sediment thickness grids as a first step in developing a paleobathymetric grid series. Three transects with a total of up to 4000 km long multichannel seismic reflection profiles from various organizations were initially used to interpret horizons in order to define the basin-wide seismostratigraphy(fig.1, fig.2). We integrated local stratigraphic models of Miller et al. (1990), Rogenhagen et al. (2004), Maldonado et al. (2006) and Rebesco et al. (2008) and expanded the 2D transect model from across the Weddell Sea of Lindeque et al. (2013) by adding more than 200 seismic lines and identified the pre-glacial to glacial sedimentary units. Borehole data of ODP Leg 113 and SHALDRIL constrain sediment ages locally. Three basic sedimentary units are identified as being deposited under pre-glacial (~148-34Ma), transitional (~34-12Ma) and full-glacial (~12-1Ma) conditions. We generated sediment depth and thickness grids of these three units. The sediment thickness grids allow us to compare the pre-glacially dominated and glacially dominated sedimentary development of the Weddell Sea. The thickest sediments are present in the southern and southwestern Weddell Sea with a maximum thickness of up to 10 km. The largest deposition centers are located in front of the Filchner Ronne Ice Shelf. In a next step of this project we will calculate paleobathymetry grids to be used to set boundary conditions for ocean circulation and climate models which help us to understand the regional ice sheet dynamics and regional oceanic circulation in previous warm periods. References Lindeque, A., Martos, Y., Gohl, K. and Maldonado, A. (2013). Deep-sea pre-glacial to glacial sedimentation in the Weddell Sea and southern Scotia Sea from a cross-basin seismic transect. Marine Geology, 336: 61-83, doi:10.1016/j.margeo.2012.11.004. Maldonado, A., Bohoyo, F., Galindo-Zaldívar, J., Hernández-Molina, F.J., Jabaloy, A., Lobo, F.J., Rodríguez-Fernández, J., Suriñach, E. and Vázquez, J.T. (2006): Ocean basins near the Scotia-Antarctic plate boundary: Influence of tectonics and paleoceanography on the Cenozoic deposits. Marine Geophysical Researches, 27: 83-107. Miller, H., Henriet, J.P., Kaul, N. and Moons, A. (1990): A fine-scale stratigraphy of the eastern margin of the Weddell Sea. In: Geological history of the polar oceans: Arctic versus Antarctic (U. Bleil and J. Thiede, eds.), pp. 131-161. Rebesco, M. and Camerlenghi, A., (2008): Late Pliocene margin development and mega debris flow deposits on the Antarctic continental margins: Evidence of the onset of the modern Antarctic Ice Sheet? Palaeogeography, Palaeoclimatology, Palaeoecology, 260: 149-167. Rogenhagen, J., Jokat, W., Hinz, K. and Kristoffersen, Y. (2004): Improved seismic stratigraphy of the Mesozoic Weddell Sea. Marine Geophysical Researches, 25: 265-282.



Item Type
Conference (Poster)
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Peer revision
Not peer-reviewed
Publication Status
Published
Event Details
Workshop on The Scotia Arc - Geodynamic Evolution and Global Implications, 14 May 2013 - 16 May 2013, Granada, Spain.
Eprint ID
32559
Cite as
Huang, X. and Gohl, K. (2013): Expanded and integrated seismostratigraphic analysis of the Weddell Sea region, Antarctica , Workshop on The Scotia Arc - Geodynamic Evolution and Global Implications, Granada, Spain, 14 May 2013 - 16 May 2013 .


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