Download Geology of the Hawaiian Islands

Dynamic Earth
Class 4
19 January 2006
Any Questions?
Today:
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Homework #1 is due
Homework #2 posted to website
Video:
Dating the Earth
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Two stratigraphic sections along with an igneous (unit A)
and metamorphic (unit B) body are shown. The beds in
the stratigraphic section are sedimentary in origin and are
right side up (not overturned). Use the principles that you
have learned in class to unravel geologic history:
Youngest
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J
I
G (A)
A (G)
F (note unconformity)
E
D
C
B
Oldest
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What radioactive elements might you use to date an
igneous rock that is approximately 1 billion years old?
Geology in the News:
Stardust
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January 15, 2006 Stardust completed 2.88
billion mile journey to a comet and back
Its mission – return interstellar dust particles to
Earth
First interplanetary probe from Earth flew deep into
space and brought back bits of a comet
 First U.S. mission designed to return samples from
another Solar System body since the Apollo
missions to the Moon in the 1960s and early 1970s
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Geology in the News: Stardust
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Astronomers think comets are the oldest, most
primitive bodies in the Solar System
Comets are frozen bodies of ice and dust
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Comets probably contain remains of materials used in the
earlier formation of the stars
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Particles returned by Stardust might even be older than the Sun
Comets are thought to contain organic materials essential for
the origin of life
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Composed of materials leftover after the planets formed around the Sun
about 4.6 billion years ago.
They may hold volatile carbon-rich elements that could provide clues to
the nature of the basic elements of our Solar System
Studying comets today may provide evidence that these socalled dirty snowballs brought water to the Earth, making life
possible
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Studying the dust should shed light on the origin of the Solar System
(age of the Earth) and origins of life on Earth
Tuesday
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Please read Chapter 2 in the text