| The ongoing collision of the Gondwana and Laurasia continents has created the Changning – Menglian suture belt through a range of orogenic deformation processes. These include orogenic belt evolution, element association difference, deep coupling situation and tectonic stress field. In west Yunnan, Changning – Menglian area has saved material composition and evolutional history of east Tethys tectonic domain, large-scale motion of the surface occurs remains unresolved. The structural character of Changning-Menglian suture belt in Wandian – Fengqing area shows the division of different tectonic units, tectonic styles, tectonic motions and tectonic stress field, so I present them into a regional stratigraphic and a tectonic framework to provide a detailed dissect of spatio-temporal variations from Mesozoic to Cenozoic.Changning – Menglian suture belt lies between the Nujiang fault belt in west and the Lancangjiang fault belt in east and is a north-southward continental structural belt which strike-slip by late west-eastward faulting. Tectonically, according to the plate tectonics combined the structural zoning from fold belt, fold-thrust belt to thrust belt, the Wandian – Fengqing region can be divided into three first-level, six secondary and seven third-level tectono-stratigraphic units. These new division supported by the regional sedimentary – palaeobiology record, geochemistry characteristic, geophysics interpretation and structural deformation.The surface structural feature has a characteristic that is bulged out to SEE-ward in Wandian – Fengqing area. From west to east, it can be divided into 5 deformation tectonic belts as extrusion – extension fault-fold tectonic belt, thrust-nappe – slipping-detachment tectonic belt, tri-extrusion fault-fold tectonic belt, backward thrust-nappe tectonic belt, collision – extension – granite tectonic belt by their differences of tectonic style. To the west, tectonic style controlled by Nujiang fault belt. The Bailang?B? anticlinorium and the Wandianba?W? synclinorium is characterized by open folds and brittle deformation. The Yingtao?Y? thrust-nappe structure and the Mengtong?MO? slipping-nappe structure is characterized by advance thrust-slipping fault and associated asymmetric folds, meanwhile, they experienced lately backward acting and characterized by backward fault. To the east, tectonic style controlled by Lancangjiang fault belt. The Mengyou?MU? anticlinorium is characterized by open folds with thrust faults. The Chazhai?C? slipping nappe structure presents form east to west, is characterized by back thrust-slipping fault and recumbent folds. The Fengqing?F? invasive magma zone has unobvious style, is characterized by parallel rhombi-crossed ductile shear zone.The B fault-fold zone and the W fold zone is controlled by Nujiang fault belt which inherited initial style controlled by plate collision, formed by extrusion buckle folding form west to east. The Y fault-fold-thrust zone is controlled by early plate collision also with dual-extrusion of the earlier uplift of Nujiang fault belt and the later uplift of Lancangjiang fault belt, and the latest north-southward extrusion. The MO basement fold-slipping-nappe zone is controlled by dual-extrusion of the earlier uplift of Nujiang fault belt and the later uplift of Lancangjiang fault belt. The impossible that basement covered the plate suture belt lead to the hidden of ophiolite. The MU fault-fold zone is controlled by Lancangjiang fault belt, formed by extrusion buckle folding form east to west. The C fold-nappe zone is controlled by the uplift of Lancangjiang fault belt, formed by several brittle-ductile thrust motion.It suggests that Changning – Menglian suture belt has been experienced six episodes of tectonic evolution from the Mesozoic to the Cenozoic.?1? Oceanic crust subduction stage from Late Permian to Middle Triassic, because of diachronous collision between Baoshan-Zhenkang and Yangtze block, meanwhile, the starting of collision orogenesis. The origin rudiment of fold and fault, with the regional foliation S2.?2? Regional crust subsidence with the form of Neo-Tethys stage in Late Triassic.?3? Continentization and Intracontinental orogenic stage from Early to Middle Jurassic, the MO slipping nappe structure formed, Wangyayan Formation and Yungouyan Formation slip-nappe covered the plate suture belt, with the partial volcanic faulting.?4? Post-orogeny and intracontinental extension stage from Late Jurassic to Cretaceous, porphyraceous granite invade.?5? Thrust structure stage from Paleogene to Miocene epoch, Dual-extrusion of the earlier uplift of Nujiang fault belt and the uplift of Lancangjiang fault belt, the C slipping nappe structure formed, Lancangyan Formation fold-thrust moved to surface with the form of recumbent fold add gentle fold, with the regional foliation S3. The different motion of faulting with the shallow brittle-ductile shear dynamic metamorphism.?6? Extension and Rifting tectonics from Pliocene epoch to Quaternary, basin and range tectonics formed stage from Pliocene epoch, vein rock formed. |
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