A GENTLE GRADUALIST IN A CATASTROPHISTS’ WORLD: REINHOLD SEEMANN’S TECTONIC THEORY OF RIES IMPACT CRATER (GERMANY)

The German geologist Reinhold Seemann (1888–1975), curator at the Wurttemberg natural history collections in Stuttgart, focussed most of his scientific work on the younger Tertiary north of the Alps. After 1936 he became especially interested in the Nordlinger Ries, an enigmatic geological structure in Southern Germany, which at that time was considered by most geologists to have originated through a volcanic catastrophe, but in the 1960s was to be reinterpreted as an impact crater. Seemann, however, adhered to a gradualist theory of Ries Basin genesis throughout his life, regarding the abundant broken and fragmented debris at Ries Basin as tectonic breccias, crushed by a hypothetical subterranean ‘wedge’ of rock slowly moving north, pushed by pressure built-up during alpine orogenesis and surfacing at the Ries area. As his correspondence with his younger colleague Helmut Holder shows, Seemann’s tectonic alternative was motivated strongly by his philosophical attitude preferring even wildly speculative and complex processes—as long as they acted gently and gradually—over any violent, catastrophic explanations however well-founded. His philosophy may have been influenced by his personal experience with two world wars, leading to his preference and campaigning for a gentle view of geological processes.