| Summary: | Currently, there is a broad interest in the development of paleotopographic models for the West Antarctic margin, which are essential for robust simulations of paleoclimate scenarios. Recent work has shown that large uncertainties in past topography reconstructions have led to false conclusions about the growth and the extend of Antarctica's ice sheet. The evolution of the polar ice sheets is one of the driving factors of global climate change. Improvements on paleotopographic models are therefore fundamental for a better understanding of the climate in the past. In this thesis, the author acquired and analyzed a new geomagnetic dataset off the West Antarctic margin, refined the South Pacific plate-tectonic reconstruction, and for the first time estimated the deformation of Antarctica's passive continental margins. The new data constrain the age of the rifted oceanic margin of West Antarctica and indicate that initial seafloor formation propagated westward from the Bellingshausen sector between ~89 and 84 Myr. In the Ross Sea area little continental deformation (<90 km) is observed prior to the breakup of Gondwana. However, further east the independent motion of the Bellingshausen microplate over a period of 22 Myr extended the continental margin by 106–304 km. Subsequent intraplate magmatism further altered the lithosphere. The rifting phase along the Pacific margin of Antarctica was comparatively short. Elsewhere in Antarctica rifting lasted much longer and was slow enough to allow for 300–400 km of margin extension. The author further determined the total sediment thickness from seismic data, calculated cross-regional total sediment thickness grids of the Southern Pacific, and derived the sediment unloaded basement topography. The data indicate that sediment thickness along the Pacific margin of Antarctica is about 3–4 km larger than previously assumed and that the sediment volume has been underestimated. Hence, the re-evaluation of erosion rates and West Antarctica's topography are eminent to improve our ...
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