Hercynian orogeny

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.

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. 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.

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