Observations of Heat Flow on Hotspot Swells

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Observations of Heat Flow on Hotspot Swells
Robert N. Harris, Oregon State Univ. Marcia K.
McNutt, MBARI

• Marine Heat and Fluid Flow
• 2. Heat Flow on Hotspot Swells
• 3. Conclusions

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Marine Heat Flow
q -k dT/dz dT/dz thermal gradient k thermal
conductivity
seafloor
each thermistor
Temperature
Time
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Subaerial versus Subsea Fluid Flow
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Costa Rica
Fisher et al., 2003
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Hawaii
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Reunion
Bonneville et al., 1997
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Crozet
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Cape Verde
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Bermuda
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Take Home Points

• High-resolution heat flow surveys at Hawaii and
  Reunion show large variability. Coarse surveys
  on other hotspot swells show increasing
  variability as volcanic edifices are approached.
  Both observations are consistent with fluid flow.
• The most likely driving force is the bathymetric
  relief of the volcanic edices coupled with thin
  to nonexistant sediment cover.
• 3. One potential outcome of fluid flow is that
  the heat flux is diminished where sublithospheric
  heat flow anomalies are expected to be the
  greatest.
• 4. In areas of hydrothermal circulation,
  conductive thermal models should be used with
  caution.