A Reactive Hydrothermal Flow Model for the Endeavour Segment, Juan de Fuca Ridge

G. Garven¹*, M.K. Tivey², C. Schardt³, & R.P. Lowell⁴

Corresponding author: grant.garven@tufts.edu
¹Dept. Geology, Tufts University, Medford, MA 02155, USA
²Marine Geochemistry Dept., WHOI, MS 8, Woods Hole, MA 02543, USA
³Inst. Min. & Econ. Geol., RWTH Aachen, D-52056, Aachen, Germany
⁴Dept. Geosciences, Virginia Tech, Blacksburg, VA 24061, USA

Abstract:
The two-dimensional finite element code RST2D [1] is being used to study the geohydrology and geochemistry of recharge zones in seafloor hydrothermal systems such as the Endeavour Segment of the Juan de Fuca Ridge. Relative to vents and other discharge features, submarine recharge zones are understudied. Numerical calculations are being made to quantify likely rates of recharge zone flow and relevant geochemical water-rock reactions, including mineral precipitation and dissolution, using a fully-coupled, 2-D, reactive flow approach. In particular the reactive flow model is being used to predict the formation and likely spatial distribution/preservation of anhydrite in the hydrothermal recharge zone, and its influence on fluid flow and heat transport. We are focusing on the effects/controls of off-ridge crustal geology and geometry, permeability, fault location, and thermal boundary conditions on the predicted size and extent of the recharge zone, and whether hydrothermal recharge is focused along extensional faults or diffused across broad areas of the seafloor. Hydrothermal flow systems located along the Endeavour Segment are being used as a representative field application because it has been the setting of numerous earlier studies of heat flow and hydrothermal circulation, which help provide constraints on the mathematical modeling.

References:
[1] Raffensperger, J.P.,1996, Advances in Porous Media 3, 185 – 305.