Open AccessNumerical modeling of phase separation at Main Endeavour Field, Juan de Fuca Ridge
Author(s) -
Singh Shreya,
Lowell Robert P.,
Lewis Kayla C.
Publication year - 2013
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1002/ggge.20249
Subject(s) - geology , permeability (electromagnetism) , ridge , boundary layer , temperature gradient , hydrothermal circulation , temperature salinity diagrams , petrology , salinity , geophysics , oceanography , mechanics , seismology , paleontology , genetics , physics , membrane , biology , quantum mechanics
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‐H 2 O 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.