A fold and thrust belt is a series of mountainous foothills adjacent to an orogenic belt, which forms due to contractional tectonics. Fold and thrust belts commonly form in the forelands adjacent to major orogens as deformation propagates outwards. Fold and thrust belts usually comprise both folds and thrust faults, commonly interrelated. They are commonly also known as thrust-and-fold belts, or simply thrust-fold belts.
Geometry Fold and thrust belts are formed of a series of sub-parallel thrust sheets, separated by major thrust faults. As the total shortening increases in a fold and thrust belt, the belt propagates into its foreland. New thrusts develop at the front of the belt, folding the older thrusts that have become inactive. This sequential propagation of thrusts into the foreland is the most common. Thrusts that form within the belt rather than at the thrust front are known as "out-of-sequence".
Map view In map view, fold and thrust belts are generally sinuous rather than completely linear. Where the thrust front bulges out in the direction of tectonic transport, a salient is formed. Between the bulges the areas are known as recesses, reentrants or sometimes embayments.
Thrust belts
Africa Thrustbelt name Age Structural style Atlas Mountains Cape Fold Belt
Asia Thrustbelt name Age Structural style Aravalli Range Precambrian Himalayas Upper Cretaceous Zagros fold and thrust belt Young and active deforming belt
Australia Thrustbelt name Age Structural styleEastern Lachlan Orogen Middle Paleozoic North-south oriented structures
Europe Thrustbelt name Age Structural style Alps Cenozoic Scandinavian Caledonides Ordovician - Devonian Carpathians Mesozoic - Tertiary
North America
Thrustbelt name Age Structural style Alaska Range Late Cretaceous - Cenozoic Thick-skin Anadyr Highlands Late Paleocene - Eocene Unknown Antler Thrustbelt Carboniferous Thin-skin Appalachians Late Paleozoic Thin-skin Arctic Cordillera Middle Devonian - Early Carboniferous Unknown Brooks Range Jurassic - Early Cretaceous, Early Cenozoic Thin-skin California Coast Ranges Late Miocene - Quaternary Transpressional Chihuahua Belt Paleocene Unknown Chugach Mountains Cenozoic Thin-skin Eurekan Fold Belt Eocene - Oligocene Unknown Innuitian Fold-Thrust Belt Late Cretaceous - Early Cenozoic Thin-skin Kuskokwim Mountains Late Cretaceous - Eocene Unknown Mackenzie Mountains Late Cretaceous - Middle Eocene Thin-skin Maria Fold and Thrust Belt Cretaceous Thick-skin North Greenland Fold Belt Middle Devonian - Early Carboniferous Unknown Northern Ellesmere Fold Belt Middle Devonian - Early Carboniferous Thin-skin Ogilvie Mountains Late Cretaceous - Eocene Thin-skin Oregon Accretionary Prism Late Miocene - Quaternary Thin-skin Ouachitas Late Carboniferous - Early Permian Thick- and thin-skin Richardson Mountains Late Cretaceous - Middle Eocene Thin-skin Rocky Mountains Paleocene to Middle Eocene Thick-skin Selwyn Fold Belt, YukonSelwyn Basin Metallogeny Yukon Geological Survey Late Cretaceous Unknown Sierra Madre Oriental Early Cenozoic Unknown Sierra Madre Occidental Cretaceous - Eocene Unknown South Canadian Rockies Late Jurassic - Eocene Thin-skin Wyoming-Utah Thrustbelt (North Sevier) Late Jurassic - Eocene Thin-skin
Much of this table is adapted from Nemcok et al., 2005Nemcok, M., Schamel, S. & Gayer, R. 2005. Thrustbelts - Structural Architecture, Thermal Regimes and Petroleum Systems. Cambridge University Press
South America
Thrustbelt name Age Structural style Magallanes (Fuegian) fold and thrust belt Late Cretaceous - Cenozoic Thin-skin Malargüe fold and thrust belt Marañón fold and thrust belt Cenozoic Thick-skin and thin-skin Central Andean fold and thrust belt Mesozoic - Cenozoic Thin skinThe evolution of the Altiplano-Puna Plateau of the Central Andes. 1997. Paipote fold and thrust belt Cenozoic Thick-skin and thin-skin
References
External links Fold and thrust belts publications