Get access
Geochemistry, Geophysics, Geosystems

Numerical modeling of phase separation at Main Endeavour Field, Juan de Fuca Ridge

Authors

  • Shreya Singh,

    1. Department of Geosciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, , USA
    Search for more papers by this author
  • Robert P. Lowell,

    Corresponding author
    1. Department of Geosciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, , USA
    Search for more papers by this author
  • Kayla C. Lewis

    1. Department of Computational Earth Sciences, Los Alamos National Laboratory, Los Alamos, New Mexico, 87545, USA
    2. Now at Department of Chemistry, Medical Technology, and Physics, Monmouth University, West Long, Branch, New Jersey, 07764
    Search for more papers by this author

Abstract

[1] Before being disrupted by a magmatic event in 1999, the vent temperatures and salinities along the axis of the Main Endeavour Field on the Juan de Fuca Ridge exhibited a quasi-steady spatial gradient in which the southern vent fluids were hotter and less saline than the northern vent fluids. We present 2-D numerical models of two phase flow in a NaCl-H2O system to understand these gradients. We consider homogenous permeability models with a range of bottom boundary temperature distributions and heterogeneous permeability models by imposing layer 2A extrusives with a constant bottom boundary temperature distribution. The aim is to understand the impact of both bottom boundary temperature and layer 2A permeability on hydrothermal fluids and to determine what combination of these controlling factors could cause the observed trend. We find that variations in bottom boundary temperature alone cannot explain the span of surface temperatures and salinities measured at the Main Endeavour Field. Heterogeneous permeability within layer 2A that has higher overall permeability in the northern part of the vent field than the southern part can reproduce the observed north to south temperature gradient, but such a permeability distribution cannot reproduce the observed salinity gradient. We conclude that both deep-seated heterogeneous permeability, perhaps localized by a fault zone, and a heterogeneous layer 2A are required to produce the trend of temperatures and salinities in vent fluids at the Main Endeavour Field prior to the 1999 event.

Get access to the full text of this article

Ancillary