Thermal Remanent Magnetization

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Thermal Remanent Magnetization

• Most rocks contain magnetic minerals, e.g.
• Magnetite (Fe3O4) Curie point 578oC
• Hematite (Fe2O3) Curie point 650oC
• When these minerals form, they adopt the magnetic
  field they form in
• The temperature (Curie point) at which their
  magnetic field locks in is lower than the
  temperature at which they crystallize

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Study Example Jurassic Quiet Zone(Woods Hole
Project)
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Timescale by Hiertzler, et al., 1968Extrapolates
reversals observed on land and correlates them to
South Atlantic seafloor
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Timescale by Cande and Kent, 1995Recalibrates
South Atlantic seafloor and connects to other
ridges worldwide
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Sea Floor Spreading
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Magnetic Anomaly Patterns
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Plate Tectonics Movie From University of
California at Berkeley Museum of
Paleontology http//www.ucmp.berkeley.edu/geology
/tectonics.html
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Earthquake Movie From NASA/Goddard Scientific
Visualization Studio HoloGlobe project http//svs
.gsfc.nasa.gov/vis/a000000/a001200/a001290/index.h
tml
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From USGS Cascades Volcanic Observatory http//vul
can.wr.usgs.gov/Glossary/PlateTectonics/Maps/map_p
late_tectonics_world.html