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molasse
molasse Molasse is a dialect word used by French-speaking farmers in western Switzerland to describe soft, friable sandstones. It was subsequently used by Studer in 1825 to describe the entire Oligo–Pliocene sedimentary sequence of the central Swiss Plateau and adjacent areas. The sequence consists of approximately 7000 m of sediments which accumulated in a subsiding foreland basin to the north of the Alps, during the later phases and after the main mountain-building movements. The sediments were deposited under alternately freshwater and marine conditions. The Lower Marine Molasse consist of marine turbidites and shallow-water deposits, and the Upper Marine Molasse of shallow-marine, tidally influenced, sediments. The Lower and Upper Freshwater Molasse consists of alluvial-fan deposits, derived from the Alps, which pass into fluvial deposits that were transported longitudinally along the basin. Whereas in the Lower fluvial interval they were transported to the north-east, in the Upper fluvial interval they were transported to the south-west.
Since Bertrand's employment of the name of 1847, molasse has been widely used outside Switzerland to describe an assemblage of sedimentary rocks thought to have accumulated in a tectonic environment comparable to that north of the Swiss Alps. G. Evans |
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Cite this article
PAUL HANCOCK and BRIAN J. SKINNER. "molasse." The Oxford Companion to the Earth. 2000. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>. PAUL HANCOCK and BRIAN J. SKINNER. "molasse." The Oxford Companion to the Earth. 2000. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O112-molasse.html PAUL HANCOCK and BRIAN J. SKINNER. "molasse." The Oxford Companion to the Earth. 2000. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O112-molasse.html |
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molasse
molasse A term originally used to describe the mainly shallow-marine and non-marine sediments produced from the erosion of a mountain belt after the final stage of uplift in an orogeny. It is now clear that much so-called molasse is not post-tectonic, but syntectonic, developed from the erosion of nappes while uplift and deformation are still progressing; some workers therefore consider that the term should be discontinued. See FLYSCH.
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Cite this article
AILSA ALLABY and MICHAEL ALLABY. "molasse." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 27 May. 2012 <http://www.encyclopedia.com>. AILSA ALLABY and MICHAEL ALLABY. "molasse." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (May 27, 2012). http://www.encyclopedia.com/doc/1O13-molasse.html AILSA ALLABY and MICHAEL ALLABY. "molasse." A Dictionary of Earth Sciences. 1999. Retrieved May 27, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-molasse.html |
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