Structural setting and evolution of the Afghan orogenic segment – a review
Agemar Siehl, 2017. "Structural setting and evolution of the Afghan orogenic segment – a review", Geological Evolution of Central Asian Basins and the Western Tien Shan Range, M.-F Brunet, T. McCann, E. R. Sobel
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The actual state of knowledge concerning the tectonic evolution of the Afghan orogenic segment is summarized in the context of the neighbouring regions. The segment can be divided into: (1) the Late Palaeozoic North Afghan Variscan domain, which forms the southern margin of the Turan Plate; (2) the Early Cimmerian (Late Triassic–Early Jurassic) Palaeotethys suture zone of Middle Afghanistan, with the associated magmatic arc and back-arc rift extending from the Parapamisos and western Hindu Kush to the northern Pamir Mountains; (3) the Late Cimmerian (Late Jurassic–Early Cretaceous) domain of the Central Afghan Block mosaic with Gondwana-derived terranes; and (4) the Cenozoic-age Himalayan domain, which fringes the Cimmerian domain along the transpressive boundary of the Indian Plate in the east and the accretionary complex of the Makran subduction zone in the south. This current review of the scattered literature of a country where geological fieldwork effectively ceased 35 years ago is intended to bridge the gap between the better-known regions to the west in eastern Iran, and to the east in the Pamir–Punjab syntaxis.
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The geological evolution of Central Asia commenced with the formation of a complex Precambrian–Palaeozoic orogen. Cimmerian blocks were then accreted to the southern margin in the Mesozoic, leading to tectonic reactivation of older structures and discrete episodes of basin formation. The Indian and Arabian blocks collided with Asia in the Cenozoic, leading to renewed structural reactivation, intracontinental deformation and basin development.
This complex evolution resulted in the present-day setting of an elongated Tien Shan range flanked by large Mesozoic–Cenozoic sedimentary basins with smaller intramontane basins distributed within the range.
This volume presents multidisciplinary results and reviews from research groups in Europe and Central Asia that focus on the western part of the Tien Shan and some of the adjacent large sedimentary basins. These works elucidate the Late Palaeozoic–Cenozoic tectono-sedimentary evolution of the area. Emphasis is given to the collision of terranes and continents and the ensuing fault reactivations. The impact of climatic changes on sedimentation is also examined.