Numerical modeling of the thermal structure and evolution of hydrothermal systems

This study applies the fluid flow and heat transport code CSMP++ to simulate the cooling of intrusions and the sub-surface structure and evolution of hydrothermal systems. These 2D simulations are focused on characterizing the influence of important factors such as magma chamber depth as well as system-scale permeability. Preliminary results show that the depth of the intrusion plays an important role in system evolution. If the roof of the intrusion is near 2-2.5 km depth, extensive two-phase zones develop above the intrusion and are able to transport heat much more rapidly than for liquid-dominated upflow zones associated with deeper intrusions. Higher host rock permeability results in lower upflow temperatures and thus two-phase zones are more short-lived and confined to shallower depths; however, since the total fluid flux around the intrusion is much greater, higher permeability causes them to cool more rapidly and develop more numerous, narrower upflow zones than develop at lower permeability. In general the thermal and hydraulic structure and system lifetime can vary greatly in response to ‘small’ changes in heat source depth and system-scale permeability.