Long-Distance Lateral Magma Propagation and Pamir Plateau Uplift

Abstract

Long-distance lateral magma propagation may reflect the complex interaction between regional tectonics and crustal uplift. Here, we report observations on the Taxkorgan intrusive complex (TIC) of the Central Pamir. TIC is a 70 km long, 10–18 km wide, north-northwest–elongated body intruded into mid-upper crust in parallel with, and close to, the Kongur Shan Extensional System. New zircon U-Pb dating shows that syenite samples exhibit a clear younging pattern from south to north along the pluton axis within an interval between 11.5 and 10.3 Ma, which is interpreted as lateral magma propagation from a single feeder zone at its northwestern margin. The lateral magma propagation was caused by a combination of crustal rigidity differences, and a topography-induced pressure gradient that is nearly orthogonal to the least compressive stress. We propose that long-distance lateral magma propagation plays an important role in plateau expansion, restraining the thickness and elevation of the Pamir Plateau.