A glimpse beneath the Ekstroem shelf: First results from wide angle seismic data

• Main Authors: Fromm, Tanja, Merl, Maximillian, Schlager, Ursula
• Format: Conference Object
• Language: unknown
• Published: 2018
• Subjects: Antarc*; Antarctica; East Antarctica; Ice Sheet; Ice Shelf
• Online Access: https://epic.awi.de/id/eprint/47885/; https://hdl.handle.net/10013/epic.aaba7d08-6592-4609-b2e1-7d9ca51a8976

Drilling into marine sediments and their subsequent basement provides sound constraints on the geological history of a region. Although marine sediments have been successfully cored globally, the most valuable information about the paleo ice sheet evolution of East Antarctica is hidden in the inaccessible sub ice shelf deposits in our research area. Drilling of the presumably Cretaceous-Cenozoic sediments and the underlying basaltic basement is planned at the Ekstroem Ice Shelf. Thus, in the austral summer season 2016/17 an over-ice seismic presite survey was conducted to gain information on the sediment and basement structures. In this context, a precise depth estimate of the target horizons/basement is of critical importance for selecting the best drill sites. To achieve this, we installed seismic recording stations along several seismic reflection lines to record the refracted seismic energy at long offsets. In total, we setup 14 stations along 8 profiles. The number of stations per profile varied between 1 and 5 with a spacing of 7 to 13 km. Each station was equipped with a Reftek 130 recorder and 9 geophone chains consisting of six 4 Hz vertical components. The source was a 9-ton EnviroVibe vibrator with a maximum pressure of 57 kPa emitting a 10 s linear sweep within a frequency range of 10 to 220 Hz. The shotpoint distance was 120m. Here we present technical details and challenges of the experiment, the data processing and the first preliminary results.