A Study of the Kunlun‐Qilian‐Qinling Suture System

Abstract

The Late Neoproterozoic-Early Palaeozoic suture zones within the Central Orogenic Belt of China can be considered a system-the Kunlun-Qilian-Qinling suture system (KQQ suture system). It is basically divided into the western, central and eastern sectors. The western sector consists of the KUda-Subashi suture zone, the Mazar-Kangxiwar suture and the central West Kunlun microblock. The cenbal sector covers the following five suture zones: the Altun, North Qilian, Qaidam northern marginal, Qimantag-Wutuo and East Kunlun southern marginal sutures, in addition to some microblocks such as the mid-south Qilian. Qaidam. Ayakkum and Maqen microblocks. The eastern sector is composed of the Shangdan suture zone, Mianlile suture zone and central Qinling-Dabie microblock. The KQQ suture system experienced (1) extending-rifting of the Rodinia supercontinent in the early-middle Sinian (-78(Moo Ma); (2) the formation and evolution of the KQQ archipelagic ocean during the Late Sinian-ordovician (-600-440 Ma), and (3) closing of the KQQ Ocean and forming of the KQQ suture system during the Late Ordovician-early Silurian (-440400 Ma). As a system comprising many suture zones and microblocks. the KQQ suture system constitutes the foundation of the Central Orogenic Belt of China.

Basin‐ and Mountain‐Building Dynamic Model of “Ramping‐Detachment‐Compression” in the West Kunlun‐Southern Tarim Basin Margin

“…4b and 4c). Therefore the three high-velocity zones ( Bian et al, 2002) or remnant oceanic crustal fragments that have not been completely consumed, and may serve as indicators for the occurrence of plate subduction and inherited intracontinental subduction at the earlier stage. Vertically, there is great difference in velocity structure above and below 100 km depth: below 100 km depth the interface between the high-velocity and low-velocity perturbations generally dips steeply or nearly upright to the north, while above 100 km depth the interface between the high-velocity and low-velocity perturbations largely dips gently toward each other to the north and south with the Karatag terrane as the axial zone.…”

“…The age of the Hoh Xi1 alkaline volcanic rocks is 17.3-1.08 Ma, indicating that the formation age of high-temperature melts (molten layers) or thermal plumes in the West Kunlun and the interior of the Qinghai-Tibet Plateau may be at least traced back to the Miocene. It follows thus that sustained, strong magmatism has occurred in the region since the Miocene, which is inferred to be related to partial melting of delaminated lithospheric blocks and crustmantle mixing resulting from polyphase (from the Late Paleozoic-Early Mesozoic through the Mid-Late Triassic, Mid-Late Jurassic and Late Cretaceous) ocean-continent subduction (plate collision) and intracontinental subduction that occurred (Cui et al, 1999;Bian et al, 2002;Xu et al, 2006 ). The derivation of magmas from the thickened basal continental crust or mixed crustmantle layer (Lai, 1999) furnishes more direct geochemical evidence related to alkaline volcanic activity and intracontinental subduction.…”

“…Early stage: Late Jurassic-Early Cretaceous ramping-rapid uplift and subsidence. Since the Early Paleozoic the region south of the Kunlun Mountains had undergone polyphase ocean-continent and continentcontinent collisions (Ding et al, 1996;Matte et al, 1996;Cui et al, 1999Cui et al, , 2006bTapponnier et al, 2001;Xu et d., 2001Xu et d., ,2006Bian et al, 2002); as a result, large amount of deep material beneath the West Kunlun tectonic belt were concentrated and migrated upward along the central Kunlun junction belt (i.e. the Oytag-Kuda-Kaxtax fault and Bulungkol-Kangxiwar fault).…”

“…the block have a "face-to-face" horizontal compression Tarim block has been subducted beneath the West Kunlun Mountains (Burtman and Molnar. 1993; Matte et a] Bian et al, 2002;Xue et al, 2004;Wu et al, 2007). Therefore, a number of researchers consider the bidirectional subduction, i.e.…”

Major Characteristics of the Lajishan Orogenic Belt of the South Qilian Mountains and Its Geotectonic Attribute

“…However, there are a number of geologists who argued for its existence (e.g. Zeng et al, 1997;Yang et al, 2000, Bian et al, 2001. Their major lines of evidence are:…”