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The Variscan or Hercynian orogeny is a geologic mountain-building event caused by Late Paleozoic continental collision between Euramerica (Laurussia) and Gondwana to form the supercontinent of Pangaea. ==Nomenclature== The name ''Variscan'', comes from the Medieval Latin name for the district ''Variscia'', the home of a Germanic tribe, the Varisci; Eduard Suess, professor of geology at the University of Vienna, coined the term in 1880. (Variscite, a rare green mineral first discovered in the Vogtland district of Saxony in Germany, which is in the Variscan belt, has the same etymology.) ''Hercynian'', on the other hand, derives from the Hercynian Forest. Both words were descriptive terms of strike directions observed by geologists in the field, ''variscan'' for southwest to northeast, ''hercynian'' for northwest to southeast. The ''variscan'' direction reflected the direction of ancient fold belts cropping out throughout Germany and adjacent countries and the meaning shifted from direction to the fold belt proper. One of the pioneers in research on the Variscan fold belt was the German geologist Franz Kossmat, establishing a still valid division of the European Variscides in 1927. The other direction, ''Hercynian'', for the direction of the Harz Mountains in Germany, saw a similar shift in meaning. Today ''Hercynian'' is often used as a synonym for ''Variscan'', but is somewhat less used than the latter.〔Google search on December 29, 2007: ca. 44.500 for ''Variscan orogeny'', ca. 15.000 ''Hercynian orogeny''. In German: 1.170 for "variszische Orogenese", 154 for "herzynische Orogenese".〕 In the USA it is only used for European orogenies; the contemporaneous and genetically linked mountain-building phases in the Appalachian Mountains have different names.〔(''Tectonics of the Devonian'' ). Website of University of California Museum of Paleontology. Accessed on December 29, 2007.〕〔(''Historical Geology: The Hercynian Orogeny'' ). Historical Geology, University of North Texas. Accessed on December 29, 2007.〕 The regional term ''Variscan'' underwent a further meaning shift since the 1960s. Geologists generally began to use it to characterize late Paleozoic fold-belts and orogenic phases having an age of approximately 380 to 280 Ma. Some publications use the term ''Variscan'' for fold belts of even younger age, deviating from the meaning as a term for the North American and European orogeny related to the Gondwana-Laurasia collision. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Variscan orogeny」の詳細全文を読む スポンサード リンク
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