The structural positions of the ophiolite complex in the Earth crust of the western Tien-Shan

Abstract

The westernmost parts of the Tien Shan region are located between two areas of crustal suturing, formed by the closure of the Turkestan Ocean, and probably the closure of a second ocean, the Gissar Ocean. Regional correlation of these sutures, however, has been problematic due to the lack of geological and geophysical data, as well as conflicting interpretations within the literature of various geological bodies. We summarize the information about Paleozoic ophiolites of westernmost parts of the Tien Shan for the international geoscientific audience from the literature and our own unpublished data. We focus on the best-known examples of Southern Tien Shan ophiolites which are remnants of Paleo-Asian Ocean, aligned in two main belts in Uzbekistan. Ophiolites reveal a wide age spectrum ranging from the Ordovician to the Devonian on the northern slope of Southern Tien Shan, and the Early Carboniferous on the southern slope. Considering all data on these ophiolites as well as regional considerations lets us conclude that a single ocean located subduction of the Turkestan Ocean basin under the northern Karakum-Tadjik terrane caused back-arc continentalo ruisft.i ngo iunththwearGdi ssar region in Early Carboniferous resulted in the formation of a small basin with oceanic crust. By late Carboniferous/early Permian times, both oceanic basins were subducted.