Uplift of Zagros Mountains slows plate convergence



Research has indicated that mountain ranges can slow down the convergence between two tectonic plates on timescales as short as a few million years, as the growing mountains provide enough tectonic force to impact plate motions. Focusing on the convergence of the Arabian and Eurasian plates at the Zagros mountain range, which runs across Iran and Iraq, Austermann and Iaffaldano reconstructed the relative motion of the plates using published paleomagnetic data covering the past 13 million years, as well as current geodetic measurements. They show that the convergence of the two plates has decreased by about 30% over the past 5 million years. Looking at the geological record to infer past topography and using a computer model of the mantle-lithosphere system, the authors examined whether the recent uplift across the Zagros Mountains could have caused the observed slowdown. They also considered several other geological events that might have influenced the convergence rate, but the authors were able to rule those out as dominant controls. The authors conclude that the uplift across the Zagros Mountains in the past 5 million years did indeed play a key role in slowing down the convergence between the Eurasian and Arabian plates. (Tectonics, doi:10.1002/tect.20027, 2013)