Late Quaternary depositional history of the Reuss delta, Switzerland: constraints from high‐resolution seismic reflection and georadar surveys

Abstract

Glacial erosion has caused overdeepening of many alpine valleys. After retreat of the ice, they were filled with heterogeneous deposits of glacial, lacustrine and fluvial sediments. A typical example of such a valley segment and its infill is the Reuss delta on the southern shore of Lake Lucerne in Switzerland. To obtain a detailed three-dimensional image of this valley segment, the ETH Institute of Geophysics has acquired several two-dimensional, high-resolution seismic and georadar profiles, and conducted a three-dimensional georadar survey. Interpretations of these geophysical data were constrained by a geological core extracted from a borehole 300 m deep near the investigation site. The seismic profiles imaged ca. 600 m of sediment infill above bedrock. Based on their reflection characteristics, five different deposition units were distinguished. These units were interpreted as a succession of clay/silt at the base, followed by different sand units with variable but generally increasing amounts of gravel. This succession represented a prograding delta that filled the southern part of Lake Lucerne. The latest fluvial development of the region is best represented by the georadar data. In particular, the three-dimensional georadar data set provides a detailed view of an ancient braided river channel

High‐resolution reflection seismics reveal the structure and the evolution of the Quaternary glacial Tannwald Basin

“…Among the geophysical methods, the seismic reflection method yields the highest resolution to image the whole infill (e.g. Pfiffner et al 1997;Nitsche et al 2002;Brückl et al 2010;Reitner et al 2010). High-resolution seismic data are usually acquired on lakes (van Rensbergen et al 1998(van Rensbergen et al , 1999Morend, Pugin and Gorin 2002); onshore seismic data with a sufficient amount of detail are rare (e.g.…”

High‐resolution water content estimation from surface‐based ground‐penetrating radar reflection data by impedance inversion

“…The success of GPR imaging would most likely only be limited at sites with significant dispersive attenuation (e.g., clay‐rich sediments [ Arcone et al , 2008]). A large number of successful GPR reflection imaging studies document the wide range of environments suitable for GPR imaging [e.g., Beres and Haeni , 1991; Smith and Jol , 1992; Beres et al , 1995, 1999; McMechan et al , 1997; Tronicke et al , 1999; Nitsche et al , 2002]. If moderate dispersion effects are observed, techniques such as proposed by Turner [1994] or Irving and Knight [2003] could be applied to ensure a stationary wavelet.…”