Shallow Crustal Deformation Research Articles

Structure and tectonic evolution of the Tongbai‐Dabie Range in the East Qinling Collisional Belt, China

Recent work demonstrates that the Tongbai‐Dabie Range, which is considered to be the eastern segment of the important Qinling belt in central China, shows ample evidence of the collisional nature of this orogenic zone. It is characterised by large thrust‐decollement structures with at least 140 km of horizontal displacement, and it includes a melange nappe, overthrust continental crust, underthrust continental crust, a marine‐nonmarine molasse formation, and a foreland fold‐thrust belt. Its interpreted tectonic evolution can be subdivided into four main periods: (1) ocean‐continent north dipping subduction during the Silurian‐Early Devonian, (2) continental collision in the late Devonian, (3) intracontinental subduction and large‐scale shallow crustal deformation beginning in the middle Carboniferous, and (4) upwarping and slicing by huge E‐W left‐lateral strike‐slip faults after the late Jurassic and before the Cenozoic right‐lateral movements on the faults which bound this belt.

Deformation Characteristics and Tectonic Evolution of the Eastern Qinling Orogenic Belt*

Abstract The Qinling Mountains separating the northern from the southern China plate is a key region for the study of structural evolution of eastern Asia. It is composed of the Palaeozoic fold belt in its northern part and the Variscan and Indosinian fold belts in its southern part. The evolution of the former is marked by the closure of a northward subducting oceanic basin in the early stage, followed by southward obduction of ophiolites and intracontinental thrusting during the Variscan; whereas that of the latter is represented by intracontinental, shallow crustal deformation on the basis of a large‐scale detachment structure (with a horizontal slip of at least of 100 km). Since the late Palaeozoic, however, both of the belts have been cut by a series of east‐west sinistral strike‐slip faults.

Tectonics of the Qinling Belt: build-up and evolution of eastern Asia

The structure and history of the Qinling range, which separates the North and South China cratons, are a key to the tectonic evolution of eastern Asia. The mountain range is composed of a northern Palaeozoic belt and a southern Mesozoic belt. The Palaeozoic orogeny probably involved the closure of an oceanic basin along a north-dipping subduction zone, followed by south-vergent obduction of ophiolites and intracontinental thrusting during the Devonian. The Mesozoic belt appears to be the product of purely intracontinental, shallow crustal deformation over a large decollement with at least 100 km of horizontal transport. Since the Devonian, both belts have been sliced by huge east–west sinistral strike-slip faults.