paleomagnetism
Fossil magnetic fields
Paleomagnetism is the study of Earth's magnetic field as recorded in rocks.
When volcanic rocks cool or sediments settle, magnetic minerals align with the prevailing magnetic field and preserve its direction and intensity.
Scientists use these ancient magnetic signatures to track how continents have drifted over geological time and to document reversals in Earth's magnetic poles: Paleomagnetism provided crucial evidence for plate tectonics.
Magnetic iron ore
- basaltFine-grained volcanic stone
- igneous rocksStone from cooled magma
- sedimentaryFormed from deposited material
- lava flowsMoving volcanic rock
Gradual landmass repositioning
- plate boundariesEdges of crustal sections
- subductionPlate descending beneath another
- lithosphereCrust plus upper mantle
- asthenosphereDuctile upper mantle layer
tectonic plates · Pangaea · Gondwana · mid-ocean ridge · terrane · microcontinent · supercontinent · ocean floor
Study of rock layers
- polarityState of opposing forces
- secular variationLong-term magnetic field shift
- inclinationDisposition toward something
- core samplesCylindrical sections extracted by boring
Study of geological ages
- radiometricMeasuring by radiation
- potassium-argonIsotopic age-determination technique
- correlationStatistical relationship measure
- time scaleDuration measurement system
Strong atomic magnetic alignment
- paramagneticWeakly attracted to magnets
- diamagneticRepelled by magnetic fields
- anisotropyDirection-dependent property variation
- grain sizeParticle dimension measurement
magnetite
Magnetic iron ore
- basaltFine-grained volcanic stone
- igneous rocksStone from cooled magma
- sedimentaryFormed from deposited material
lava flows · magnetization · hematite · hysteresis · demagnetization
continental drift
Gradual landmass repositioning
- plate boundariesEdges of crustal sections
- subductionPlate descending beneath another
- lithosphereCrust plus upper mantle
asthenosphere · tectonic plates · Pangaea · Gondwana · mid-ocean ridge · terrane · microcontinent · supercontinent · ocean floor
stratigraphy
Study of rock layers
- polarityState of opposing forces
- secular variationLong-term magnetic field shift
- inclinationDisposition toward something
core samples · Gauss · Gilbert
geochronology
Study of geological ages
- radiometricMeasuring by radiation
- potassium-argonIsotopic age-determination technique
- correlationStatistical relationship measure
ferromagnetism
Strong atomic magnetic alignment
- paramagneticWeakly attracted to magnets
- diamagneticRepelled by magnetic fields
- anisotropyDirection-dependent property variation
magnetometer
Instrument measuring field strength
pottery
Fired clay objects