The Palaeo‐Tethyan suture: A line of demarcation between two fundamentally different architectural styles in the structure of Asia

Abstract

The Palaeo-Tethyan suture separates regions characterized by two fundamentally different tectonic styles in the structure of the Tethysides. North of the suture in Iranparts of the Russian Federation and China, orogenic development is characterized by very large subduction-accretion complexes developed since the late Proterozoic. Magmatic arc axes migrated radially outwards from the 'Old Vertex of Eurasia' and consolidated the accretionary prisms into a 'basement complex' dominated by a pelitic composition.In such orogens, called the 'Turkic-type' after the dominant ethnic population of Central Asia, ophiolites are unreliable indicators of sutures, because they are present throughout the 'basement' as in-faulted shreds and rarely as nappes. By contrast, south of the Palaeo-Tethyan suture, orogeny was commonly characterized by a Sumatra-or Andean-type continental margin arc (e.g. the Transhimalaya arc) that in places became an island arc by back-arc basin rifting (e.g. the Black Sea behind the Rhodope-Pontide fragment) and later collided with an Atlantic-(as in the Himalaya) or California-type (as in the Alps) continental margin to create Alpine-or Himalayan-type orogenic belts. Turkic-type orogenic belts result from the exaggeration of the Himalayan-type as a result of the subduction of very large oceanic areas that contain great amounts of sediment. They contribute to the enlargement and also possibly the growth of the continental crust which has a composition more silicic than basalt. The Palaeo-Tethyan suture is thus a line across which the rate of continental enlargement by subduction-accretion changed dramaticallv.

Apatite fission-track thermochronological constraints on the pattern of late Mesozoic–Cenozoic uplift and exhumation of the Qinling Orogen, central China

“…Therefore, the Qinling Orogen was characterized by uplift in the south and subsidence in the north during the Late Jurassic-Early Cretaceous. Meanwhile, the South China Block subducted northwards toward the Qinling Orogen and rotated clockwise (Meng et al, 2005;Ratschbacher et al, 2003), a process that was influenced by the opening of the Neo-Tethys, the northward accretion of the Cimmerian continent, and the westward subduction of the Pacific Plate (Ratschbacher et al, 2003;Sengor, 1992). At the same time, the S-NCB was located at the trailing edge of the extensional environment, which was formed by multi-directional convergent motion, including the northward subduction of the South China Block and the westward subduction of the Pacific Plate (Dong et al, 2008;Meng et al, 2007).…”

Reconstruction of the Altyn Tagh fault based on U‐Pb geochronology: Role of back thrusts, mantle sutures, and heterogeneous crustal strength in forming the Tibetan Plateau

“…A regional marker is needed to determine total offset due to the complexity and width of this system. Although sutures could serve this purpose [e.g., Chinese State Bureau of Seismology , 1992; Sobel and Arnaud , 1999; Yin and Nie , 1996], establishing correlations is hampered by extensive deformation of the suture belts in the western Kunlun Shan and Altyn Tagh region, and the possibility that these materials represent a complex series of back arc basins [ Hsü , 1988; Hsü et al , 1995; Yao and Hsü , 1992] or materials entrained within subduction‐accretion complexes [ Sengör , 1992; Sengör and Natal'in , 1996; Sengör and Okurogullari , 1991]. …”

Ophiolitic mélanges in crustal-scale fault zones: Implications for the Late Palaeozoic tectonic evolution in West Junggar, China

“…Generally, the ophiolitic mélanges are often overthrusted by ultramafic or ophiolitic nappes and mark major suture zones within continental crust, because they represent the remnants of accreted fragments of vanished oceans. Therefore, ophiolites and/or mélanges found in the field are usually regarded as sutures [Dewey, 1977[Dewey, , 2005Smith and Colchen, 1988;Şengör, 1992;Xiao et al, 2014]. However, some ophiolitic mélanges, as stressed by Gansser [1974] and Orange [1990] may develop in shear zones or by diapirism from deep-ocean fracture zones.…”