Late Quaternary tectonic movements of western and central Asia

Abstract

Late Pleistocene and Holocene activity on major faults of western and central Asia are inferred from offsets of young topography. Large active strike-slip faults bound the northward-moving Arabian and Indian plates. The Indian plate moves more rapidly with respect to Eurasia than does the Arabian plate, with the highest rate of young lateral motion (1.2 to 1.4 cm/yr) along the Darvaz fault on its northwestern side. Convergence of these plates on the Eurasian plate produces the north-trending compression of the latter. It results in the creation of northwest-trending dextral wrench faults, smaller northeast-trending sinistral faults, east-west-trending thrust faults, and rare north-trending normal and extension faults. The rates of relative motion are slower here than on the borders of the southern plates, being higher to the north of the Indian plate than to the north of the Arabian. Not all relative motion of the southern plates is accommodated by their boundary deformation and by the compression of the Eurasian plate. This motion and resistance of the Eurasian plate produce squeezing of the rock masses on both sides of the southern plates that results in dextral west-trending wrench faulting on the western side and sinistral on the eastern side of each plate. This pattern can be recognized throughout the Neogene-Quaternary tectonic evolution of the Asian segment of the Alpine-central Asian orogenic belt. This paper is an attempt to correlate synchronous tectonic movements over huge areas of the continent. The author believes it is appropriate to recognize in such correlation mobile and stable zones of different scales. The depth and character of motion in the mobile zones define important features of the structure and evolution of the Earth's crust. © 1978 Geological Society of America.