The drill site BASA (yellow dot on map) will explore the overdeepened Basadingen Trough in Northeastern Switzerland. The Basadingen overdeeping formed during the Middle Pleistocene a valley that connected the Thur Valley in the South with the Rhine Valley in the North. The maximum sediment thickness is of up to 300 m south of the drill site. The seismic site survey revealed a multiphase infilling architecture with possibly two, partly crosscutting generations of erosion/sedimentation cycles. These likely represents different glacial erosion pulses of the western lobe of the Rhine Glacier.
The seismic site surveys reveal a multiphase stratigraphy showing a series of unconformities (colored lines). This internal architecture indicates that the trough was filled as a result of multiple glacial sequences (bold letters). The overdeepening reaches a maximum depth of ca. 300 m. The coring site (black) is located so that the drill core will recover a maximum number of sequences in well-layered facies including bedrock (Molasse, M), that is expected in ~250 m depth.