Analysis of a conductive heat flow profile in the Ecuador fracture zone

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doi: 10.1016/j.epsl.2017.03.024
Author(s): Kolandaivelu, Kannikha Parameswari; Harris, Robert N.; Lowell, Robert P.; Alhamad, Ahmed; Gregory, Emma P. M.; Hobbs, Richard W.
Author Affiliation(s): Primary:
Virginia Polytechnic Institute and State University, Department of Geosciences, Blacksburg, VA, United States
Oregon State University, College of Earth, Ocean, and Atmospheric Sciences, United States
Durham University, Department of Earth Sciences, United Kingdom
Volume Title: Earth and Planetary Science Letters
Source: Earth and Planetary Science Letters, Vol.467, p.120-127. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0012-821X CODEN: EPSLA2
Note: In English. 31 refs.; illus., incl. sects., 2 tables, sketch maps
Summary: We report 18 new conductive heat flow measurements collected from a sediment pond located in the inactive part of the Ecuador Fracture Zone in the Panama Basin. The data were collected along an east-west transect coincident with a multi-channel seismic reflection profile that extends from ODP Hole 504B to west of the sediment pond. Conductive models indicate that heat flow should decrease from ≈400 mW m-2 on the 1.5 Ma western plate to ≈200 mW m-2 on the 6 Ma eastern plate; however the observed heat flow increases nearly linearly toward the east from approximately 140 mW m-2 to 190 mW m-2. The mean value of 160 mW m-2 represents an average heat flow deficit of ≈50%, which we attribute to lateral advective heat transfer between exposed outcrops on the western and eastern margins of the sediment pond. We apply the well-mixed aquifer model to explain this eastwardly flow, and estimate a volumetric flow rate per unit length in the north-south direction of ≈400±250m2yr-1 through the basement aquifer. Using a Darcy flow model with the mean flow rate, we estimate permeabilities of ∼10-11 and 10-12m2 for aquifer thicknesses of 100 and 1000 m, respectively. The estimated permeabilities are similar to other estimates in young oceanic upper crust and suggest that vigorous convection within the basement significantly modifies the thermal regime of fracture zones. Additional heat flow data are needed to determine the prevalence and importance of advective heat transfer in fracture zones on a global scale.
Year of Publication: 2017
Research Program: ODP Ocean Drilling Program
Key Words: 18 Geophysics, Solid-Earth; Advection; Aquifers; Basement; Convection; Crust; DSDP Site 504; East Pacific; Ecuador fracture zone; Equatorial Pacific; Fluid flow; Fracture zones; Geophysical profiles; Geophysical surveys; Heat flow; Heat transfer; Multichannel methods; North Pacific; Northeast Pacific; Ocean Drilling Program; Oceanic crust; Pacific Ocean; Panama Basin; Permeability; Sedimentation rates; Seismic profiles; Surveys; Thermal conductivity; Thermal regime; Upper crust
Coordinates: N011335 N011338 W0834348 W0843700
Record ID: 2017046000
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands