Download Edible Tectonics - KMS 8th Science

Edible Tectonics:
Examining
The Theory of
Plate Tectonics
Earth's Interior
What statistics surprise you?
Remember:
The oceanic
crust is thinner
than continental
crust.
COOL!
HOT!
Convection in the mantle moves the crust.
Earth's Plates Move In
Three Different Ways:
Features & Events Found along Divergent
Plate Boundaries:
• Rift (on land) or Ridge (underwater)
• Small, spewing volcanoes
• Small, frequent earthquakes
• Small "mountains"
• Sea-floor Spreading (how the Atlantic
Ocean grew to be the size it is... and it is
still getting wider, about 1" per year)
• New crust forms
• Faults (remember… cracks)
Features & Events Found along
Convergent Plate Boundaries (when one
plate is an ocean):
• Mega-thrust earthquakes
• Violently erupting volcanic mountains
(which become islands if they form
underwater)
• Subduction (crust is destroyed)
• Trenches (underwater)
• Faults
• Folded mountains (usually volcanic)
Features & Events Found along
Convergent Plate Boundaries (when
both are continental):
• Earthquakes
• Gigantic, folded mountains
• Faults
Features & Events Found along
Transform Plate Boundaries:
• Earthquakes
• No igneous rocks
• Little or no other geologic features
to observe
Let's Review the Three Plate Boundaries:
Animation (see my website for these animations):
http://www.wwnorton.com/college/geo/egeo2/content/animations/2_1.htm
Earth's Plate Boundaries
Understanding how plates interact
helps to explain why earthquakes
and volcanoes happen where they
do on Earth with one exception...
Sometimes volcanoes are found
at the interior of a tectonic
plate... Hmmm... Scientists call
that a hotspot, which is a weak
spot in the middle of a tectonic
plate where magma surfaces &
a volcano forms; hotspots track
the movement of the plate
because the "spot" is thought
to remain stationary.
Challenge: Show a hotspot with
the materials you have!
Animation (see my website for this animation):
http://www.wwnorton.com/college/geo/egeo2/
content/animations/2_6.htm
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Geological features & events
observed at a hotspot:
• Small, spewing volcanoes (that
can be violent)
• Older, extinct volcanoes that
have passed over the "hotspot,"
creating a line leading to the
current, active volcano
• Small, frequent earthquakes
• Small mountains
Known Major Worldwide Hotspots
It is estimated that there are several in Antarctica not shown.