Spaceship Earth: Our oasis in the emptiness of space: The dynamic planet

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Spaceship Earth Our oasis in the emptiness of
space The dynamic planet
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Alfred Wegener (1903) suggested and presented
evidence that the continents were once a single
supercontinent, called Pangea, which divided
200 Million years ago into Laurasia and
Gondwanaland and later into the continents we see
today (continental drift)
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Fossils of the land-bound lizard Lystrosaurus
were found in Africa, Antarctica and India,
suggesting that these continents were one
landmass during the life-time of this critter
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Geologic evidence for continental drift
Rocks of same age cross continents
Distribution of warm-water fossils
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Topography of Earth Huge mountain ranges (ridges,
like the Mid-Atlantic Ridge) circle the globe on
the ocean floors
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The crust of Earth consists of 11 major tectonic
plates
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Epicenters of major earthquakes tend to occur
along ocean ridges and plate boundaries
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The directions of movement of the major plates of
Earth
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Schematic diagram of an ocean spreading
center Symmetry in magnetic reversals indicates
sea-floor spreading.
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Elongated convection cells in the plastic
asthenosphere drive the overlying rigid
lithospheric plates.
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The Hawaiian island chain is a wonderful example
of plate tectonics in the middle of a plate. It
is fed by a stationary mantle plume under Loihi,
and the Pacific Plate glides over it at a speed
of 5 cm/year, carrying the islands with it in a
northwesterly direction.
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Ages of the Hawaiian islands An example of plate
tectonics associated with a mantle plume
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Where were Earths continents in the geologic
past?
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Volcanoes Pages 53 - 62

• Volcanoes are found on the surface of Earth and
  Venus Mars has fewer volcanoes with some signs
  of relatively recent volcanic activity.
• The volcanoes on Jupiter's satellite Io have
  turned the satellite inside out it is heated
  inside by the tidal flexing action of nearby
  massive Jupiter.
• Volcanoes of ice may have created some of the
  features now frozen into the bright smooth
  surface of Neptune's largest moon, Triton dark
  geyser-like plumes have been observed in the
  process of eruption on the satellite.

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Active volcanoes on Earth occur mostly along
plate boundaries
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Fire fountaining at Puu Oo, Hawaii, which has
been erupting since 1983
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Summit caldera of Mauna Loa volcano, Hawaii A
basaltic shield volcano
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Pahoehoe lava flows at Puu Oo, Hawaii.
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Aa lava flows, Puu Oo, Hawaii.
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Lava from Puu Oo, Hawaii, enters the ocean.
For more images, see http//hvo.wr.usgs.gov/kila
uea/update/images
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Mt. Pinatubo, June 12th, 1991 An explosive Island
Arc volcano in the Philippines
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Composite Volcanoes in the Andes (Chile)
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Maat Mons, Venus
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Rift zones on Venus
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Olympus Mons on Mars, the tallest mountain in the
Solar System
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Olympus Mons on Mars, compared to the Hawaiian
island chain
640 km
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Right Eruption of the volcano Pele on Jupiters
moon Io. Below Top view of volcano Pele
The volcanic plume (above) is 1,300 km wide and
600 km high.
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Water volcanism on Saturns moon Enceladus
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Dark, active nitrogen geysers on Neptunes moon
Triton. The constant direction of the black
streaks hints at a very thin atmosphere.
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The interior structure of Earth and the polar
wandering of its magnetic field.