Main Suture Zone Research Articles

The structural architecture of the footwall to the Main Uralian Fault, southern Urals

The Uralide orogen is a linear collisional belt formed during the Upper Paleozoic as a result of convergence between the East European Craton and outboard terranes, and accretion of intervening island arcs and obduction of oceanic crust onto the East European Craton. This paper presents a new structural subdivision of the southern Urals, to the west of the main suture zone, that puts this part of the mountain belt in a context similar to that of other collisional orogenic belts. This subdivision consists of a west-vergent thrust stack that is made up of an autochthonous to parautochthonous foreland basin, and a parautochthonous foreland thrust and fold belt, flanked to the east by a metamorphic thrust stack. The latter units are structurally overlain by allochthonous rocks of an accretionary complex, slope sediments, oceanic crust and high grade, eclogite-blueschist-bearing, gneiss. Where possible these units are defined on the basis of their internal stratigraphy and structure and on the nature of their bounding faults.

Tectonics of the Tongbai-Dabie fold belt

The Qinling fold belt is the northernmost branch of the Paleozoic and Mesozoic Tethys in eastern Asia and contains all the inter-reacting records of the North China Block (NCB) and the South China Block (SCB). The Tongbai-Dabie fold belt is its eastern section. The Qinling belt was a collage of two orogens. The north Qinling is a late Paleozoic collision orogen, which started with Proterozoic rifting, transforming into active continental margin during the middle Ordovician. The intermitten ophiolite fragments indicate the existence of an oceanic crust at that time. The collision that occurred in the Devonian was an east-west diachronous process. The main suture zone is marked by ophiolitic melange extending nearly 500 km. The late Mesozoic molasse, volcano-plutonic activity and huge imbricate thrust system all respond to the further shortening of the crust and adjustment of the intracontinental strain. The south Qinling east of the Nanyang Basin is located to the south of Tongbai mountain. A pile of thick Sinian-Silurian volcanic and marine clastic deposits imply another marine incursion. Its history in south Shaanxi could continue to the Mesozoic. The flysch trough represented by Xinyang group may be the key area for revealing the relationship between north and south Qinling. The discussion in the paper is mainly focused on the nature and evolution of the Tongbai-Dabie fold belt.

Crustal features of some main suture zones along the European Geotraverse

The European Geotraverse (EGT) crosses along a 4000 km profile from the North Cape to Tunisia the following main suture zones: the Tornquist-Teisseyre zone between the Baltic Shield and the Variscan realm, the transition zones between Rhenohercynian and Saxothuringian as well as between Saxothuringian and Moldanubian zones in the Variscan part of central Europe, and the collision zone between the European continent and the Adriatic microplate.