Thermomechanical Modeling of the Formation of Multi-Сhamber Intrusions for Identifying the Relationship of Plutonic Metamorphism with Gabbro-Diorite Massifs of Western Sangilen, Tuva, Russia

For the first time, a thermomechanical model of a system of multilevel magma chambers above a mantle heat source has been developed to explain the formation mechanisms of intrusive complexes and metamorphic aureoles in Western Sangilen. A model of “thermal blur” at the collision stage and a model of a local magma reservoir at the transtension stage are proposed. The magmatic process was studied using a numerical thermomechanical model of the system magma reservoir–magma transport–formation of intermediate chambers–formation of metamorphic zonal complexes around intrusions at different depth levels. Modeling explains the mosaic distribution of granulite metamorphism zones in the Sangilen block. Model estimates of the duration of intrusive processes were obtained. The change in tectonic regimes in the evolution of Western Sangilen affects the depth of emplacement of gabbro–monzodiorite massifs and surrounding metamorphic aureoles.