A belt of the earth's crust involved in the formation of mountains.
- ‘Together with the Appalachian, Caledonian and Variscan orogens, the Uralian orogeny contributed to the assembly of the late Palaeozoic supercontinent of Pangaea.’
- ‘The Delamerian Orogen is a compressional orogen developed by westward vergent folds and thrust faults.’
- ‘In the southern half of the Caledonian orogen, sedimentation in the post-Caledonian continental basins started significantly earlier, in the Mid-Devonian.’
- ‘These collision zones are known as orogenic belts, and the mountains are referred to as orogens.’
- ‘Several features of the mountain belt are atypical when compared with other Palaeozoic orogens such as the Appalachians, Caledonides and Variscides.’
1920s: from Greek oros mountain + -gen.