Alpine sedimentology: An introduction and tribute to Albert Matter and Daniel Bernoulli

Abstract

Department of Earth Sciences, ETH Zurich, Sonneggstrasse 5, CH-8092, Z€urich, SwitzerlandINTRODUCTIONSwitzerland offers a rich variety of sedimentolog-ical features, despite the fact that the country iswithout direct contact to any ocean. Its sedimen-tological richness is related to the Alpine oro-geny that not only assembled the sedimentaryproducts of different former depositional envi-ronments but also created important relief, whichtriggers many different sedimentary processes,some still ongoing. In this sense, the term ‘Alpinesedimentology’ denotes the prodigious relationbetween Alpine mountain building and sedimen-tary processes and their products in the regionsimplicated in its dynamics. The present specialissue assembles a variety of examples of ongoingresearch both on Alpine-deformed sedimentarysuccessions, as well as on sedimentary processesrelated to the Alpine orogeny, in Switzerland andelsewhere. The contributions in this issue were,for a large part, presented at a symposium inhonour of the 75th birthday of Albert Matter andDaniel Bernoulli, in November, 2011; they haveboth generously contributed to the field of sedi-mentological research in Switzerland, and it is forthis reason that this issue is dedicated to them.ALPINE SEDIMENTOLOGY ANDSEDIMENTSSwiss Alpine sediments and sedimentary rocksrepresent a great variety of depositional settings,which include formerly active and passive mar-gins and range from continental and shallow-marine environments to deep ocean basins. Inthe Swiss Alps, they span the time range fromthe Carboniferous (Capuzzo & Wetzel, 2004) totoday, and their highly metamorphic counter-parts may go back all the way to the late Pre-cambrian (Von Raumer & Neubauer, 1993).The preserved sedimentary record documentsthe palaeotectonic and palaeogeographicchanges, which assisted in shaping central Eur-ope and are summarized in Table 1 (Weissert &St€ossel, 2009). Switzerland effectively assemblesthe remains of different oceanic basins (theValais and Piemontais basins are all part of theAlpine Tethys) and their bordering shelves,which were progressively closed, partly sub-ducted, folded and thrusted in the course of theAlpine orogeny (Fig. 1).The succession of differ-ent palaeogeographic units aggregated in Swit-zerland may have been as large as 1000 km in anorth-west/south-east direction according to pal-aeotectonic reconstructions (Fig. 1). The diffe-rent composition and type of basement of theseunits dictated the formation of different tectono-sedimentary units during the Alpine orogeny(Figs 2 and 3). These units will be briefly treatedlater in this study, and complemented by adescription of the different fields related toresearch on sedimentological phenomena inAlpine depositional environments.ALPINE-DEFORMED SEDIMENTARYSUCCESSIONSBasement rocks and Carboniferous andPermian graben infillsThe polymetamorphic crystalline basement pres-ently underlying the sedimentary units of theJura Mountains, the Molasse Basin and the Alps(Fig. 3) was consolidated, uplifted and erodedduring the Late Carboniferous, and a series ofmostly east–west-oriented continental basinswas formed. The graben structures were conse-quently infilled with detrital and volcanogenicsediments, and subordinate lacustrine sedimentsand coal deposits (Matter, 1987). The sedimen-