Modelling crustal fluid glow in seamount-influenced hydrothermal systems

Robert Perrin, Rachel Lauer

Hydrothermal circulation within the oceanic crust plays a central role in regulating lithospheric cooling, chemical exchange, and seafloor habitability. Circulation occurs primarily through the upper few hundred metres of permeable basalt, where seawater flowsl aterally between recharge and discharge sites exposed at the seafloor. To investigate the impact of seamount geometry and permeability on circulation patterns and the efficiency of heat extraction, we conducted a series of numerical simulations of fluid flow, varying these parameters. Seamounts were represented as Gaussian topographic features and embedded within a permeable crust and covered by a low-permeability sediment layer.

In single-seamount models, flow developed as localized convection cells where recharge and discharge were governed by seamount size and crustal permeability. Small seamounts showed asymmetric circulation, with inflow occurring around most of the flanks and discharge limited to a narrower sector, while larger seamounts generated verticallyi ntegrated convection that vented near the summit. Two-seamount simulations demonstrated a modest dependence on spacing: even at the maximum separation tested,the edifices remained hydraulically connected through the crust. In these coupled systems,the larger seamount consistently acted as a recharge site and the smaller as a discharge site,leading to a larger area of crustal cooling compared to the single-seamount case, aligningwith similar studies.

Although these are preliminary results and further research is necessary, they highlight the sensitivity of crustal flow patterns to permeability and seamount geometry, providing insight into how interconnected flow systems may develop on ridge flanks.