Massive Diamond Cache – Earth՚s Interior YouTube Lecture Handouts

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Massive Diamond Cache - Earth՚s Interior
  • More than a quadrillion (1016) tons of diamond b/w 90 - 150 miles (145 to 240 km) More than 100 miles below earth՚s surface – no drilling
  • Within cratonic roots (deepest) — the oldest and most immovable sections of rock that lie beneath the center of most continental tectonic plates
  • Cratonic roots are shaped like inverted mountains that stretch through the Earth՚s crust and into the mantle.
  • Craton - polydeformed and metamorphosed crystalline and metamorphic rocks
  • No more exotic but a common mineral
  • Research by Ulrich Faul, a research scientist in MIT
  • Anomaly in seismic data – construct image of Earth՚s interior
  • Sound waves move at various speeds through the Earth, depending on the temperature, density, and composition of the rocks through which they travel.
  • Spikes in seismic speed was seen
  • The sound velocity in diamond is more than twice as fast as in the dominant mineral in upper mantle rocks, olivine.
  • Olivine - mafic and ultramafic igneous rocks and as a primary mineral in certain metamorphic rocks (common in subsurface but weathers quickly on surface)
  • Craton which is naturally less dense than the surrounding mantle.
  • Diamonds are forged in the high-pressure, high-temperature environment of the deep Earth and only make it close to the surface through volcanic eruptions that occur every few tens of millions of years.
  • Eruptions carve out geologic “pipes” made of rock type kimberlite (named after Kimberley, South Africa, where the first diamonds in this type of rock were found)
  • Kimberlite pipes seen in Canada, Siberia, Australia, and South Africa