The Central Asian Orogenic Belt extends from the Urals to the coast of northern China, of similar age and complexity to the Appalachian mountain belt in eastern North America. It was formed by the subduction of ancient oceans and the resulting collision of continental plates. Erosion of mountains formed by plate collision leads to thick conglomerates being deposited close to the mountain front and sandstone farther away -- a sediment package known as molasse. One critical piece of the puzzle in the Central Asian Orogenic Belt was the closure of an ocean and collision resulting in the Kalamaili Mountains in northern Xinjiang, China. Yuanyuan Zhang et al. have dated zircon mineral grains and pebbles of volcanic rocks from near the base of the molasses, and they have also dated lava flows that overlie the molasse. These ages confine the age of the molasse, and hence of the rapid uplift of the Kalamaili Mountains, to between 343.5 Ma and 345 Ma. These ages also help in the understanding of how nearby continental blocks fit into the mountain-building puzzle.
Depositional history, tectonics, and detrital zircon geochronology of Ordovician and Devonian strata in southwestern Mongolia
T.M. Gibson et al., Dept. of Geology, Colorado College, 14 E. Cache La Poudre Street, Colorado Springs, Colorado 80903, USA. Posted online 7 March 2013; http://dx.doi.org/10.1130/B30746.1.
Southern Mongolia is centrally located within the Central Asian Orogenic Belt, which is a mosaic of crustal fragments that amalgamated during one of the largest periods of crustal growth on Earth. However, the precise timing and nature of the events that formed this region remain poorly constrained. T.M. Gibson and colleagues provide the first detai
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