Trying to understand Alpine sediments—before 1950

Abstract

Most Alpine geologists, before and after the 1893–1902 breakthrough of the nappe theory, paid surprisingly little attention to sedimentological phenomena. They were preoccupied with stratigraphic and especially tectonic problems. The Alpine concept of “geosyncline” differed in several ways from the original one. In 1894, Marcel Bertrand suggested a fourfold division of “complexes” (informal lithostratigraphic assemblages) among the sediments of the Alps and of older mountain chains. For the Alps, his classification may be expanded to comprise: I, Late Variscan detritals; II, pre-rift platform sediments; III, syn-rift deposits; IV, post-rift platform and basin sediments; V, starved deep-sea formations on oceanic or thinned continental crust; VI, Bündnerschiefer or Schistes lustrés; VII, Flysch; and VIII, Molasse. The last named is not discussed here. On the European (Helvetic) margin, the processes giving rise to shallowing-upward sequences of condensed glauconite beds, shales and limestones (complex IV) were discussed for a long time. The work of Arnold Heim is particularly instructive. Gustav Steinmann was one of the first to recognize the deep-sea origin of certain rocks, especially radiolarian cherts. The controversy on the bathymetry of the Alpine seas during the oceanic and post-oceanic stages (complexes V–VII) went on until about 1950. Since 1916, the seas and islands around eastern Indonesia were proposed as analogues to the Late Mesozoic paleogeographic pattern of the Alps. Two 18th century scientists deserve a special mention: Moritz Anton Kappeler (M.A. Cappellerius, 1767) provided an actualistic interpretation of ripple marks on steep-standing sandstones, and Johann Jacob Scheuchzer (1718) understood the importance of graded bedding, which he attributed to the action of the Deluge.