TECTONICS AND PALEOMAGNETISM OF STRUCTURAL ARCS OF THE PAMIR-PUNJAB SYNTAXIS

Abstract

The Pamir-Punjab syntaxis consists of two structural arcs with the crests facing northward—the Pamir and Hindu-Kush-Karakorum arcs. These arcs are mutually disharmonious, and the exterior (Pamir) arc is more tight, as compared to the inner one. Paleomagnetic study of the Pamir arc has shown that the structures of the future Pamirs had a northeastern strike in the Paleogene and Cretaceous, and they occurred on the eastern limb of the Darvaz-Kopetdag structural arc, whose crest faces south. The Pamir arc originated after the Paleogene during the process of the formation of the Pamir-Punjab syntaxis. Knowledge of the kinematics of the Pamir arc, combined with data on the geometry of the syntaxis and the character of its boundaries, enable us to choose a model of the development of the syntaxis. The process of “plastic flow” of crustal masses around the underthrusting segment of the Indian plate was likely of paramount importance.