Kazakhstania

Kazakhstania (), the Kazakh terranes, or the Kazakhstan Block, is a geological region in Central Asia which consists of the area roughly centered on Lake Balkhash, north and east of the Aral Sea, south of the Siberian craton and west of the Altai Mountains. The Junggar basin in Xinjiang, China, is also part of Kazakhstania, though sometimes referred to as the Junggar Block. Because the Kazakh terranes merged during the Late Ordovician as part of the Central Asian Orogenic Belt they are also referred to as the Kazakh Orogen. These terranes are located in what is today Kazakhstan, north-eastern Uzbekistan, northern Kyrgyzstan and south-western China. Today Kazakhstania is surrounded by three large, former continents: to the north-east the Gornostaev Shear Zone separates it from Siberia with which it collided during the Carboniferous; to the north-west is Baltica which lay adjacent to the Kazakh Tourgai terrane but far away from Kazakhstania; to the south and east was Gondwana stretching from the South Pole to the Equator. Not far away from the dispersed Kazakh terranes were South China, North China, and Tarim, but how these continental blocks were positioned relative to Gondwana is not known.

==Tectonic evolution== In the Early Palaeozoic the Kazakh terranes were widely distributed north or northeast of the Mangyshlak, Karakum, Karakoram and Tarim terranes. The location, origin, and faunal affinities of these terranes has, however, been the subject of two competing hypotheses: one described these terranes as an enormous island arc called the Kipchak arc, the other as a series of more or less parallel belts. Faunal analyses indicate that some of the terranes probably originated in Gondwana rather than Baltica or Siberia. A 2006 analysis of brachiopods indicated that the Chu-Ili Mountains must have formed an independent, Peri-Gondwanan terrane in the Late Ordovician located not far from the North and South China cratons.