Thermomechanical interactions between crustal magma chambers in complex tectonic environments: Insights from Eastern Turkey

Abstract

Crustal segments, such as those in Eastern Turkey, which host magma chambers, volcanoes, and fault zones, experience complex stresses generated through interactions between regional tectonic loading, magmatic pressure, and geothermal dynamics. Here we model these competing loading mechanisms and examine their effects on generating stresses in a complex crustal segment which has been subjected to orogenesis and hosted voluminous magma discharge. This simulated-region hosts several volcanoes, thermal fields and has experienced complex tectonic deformation which manifests as crustal faults. We present a suite of purely thermal models to show the temperature distribution within the crust assuming an arrangement of crustal magma chambers and a realistic geothermal gradient. We also present a suite of linear elastic mechanical models to investigate the effect of magma pressure and regional tectonic loading in the absence of temperature variations using different arrangements of magma chambers and faults. Finally, we present coupled linear elastic thermomechanical models that highlight the influence of temperature on the distribution of both crustal stresses and deformation using the same complex geometries. Results show that thermal stresses generate two competing consequences, 1) they increase the level of shear stress around the magma chambers, potentially leading to fault nucleation or reactivation, and 2) they partially act to suppress the level of tensile stress originally generated both by magma pressure and tectonic loading. This implies that for any magmatic recharge event, which increases the internal magma chamber pressure, the contribution of temperature increase in the surrounding host rocks must also be taken into account when considering the distribution, magnitude and type of stresses around magma chambers in such crustal environments.