Download Formation of Earth - GSHS Mrs. Francomb

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Events & Evidence
*Event:
The Earth formed by dust
and minerals sticking together in the
nebula
*Evidence:
Salt sticks together in
space, so minerals and dust must
too.
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*Event:
The Earth completely melted
from radioactive elements
*Evidence:
The Earth has internal
layers: core, mantle, and crust
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*Event:
The Earth and the whole
solar system formed about 4.6 billion
years ago
*Evidence:
Radiometric dating of
meteorites
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*Event:
The Earth survived a giant
impact
*Evidence:
Moon rocks are low in
iron, so must be formed from Earth’s
crust material that got knocked off
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*Event:
A thick crust and continents
formed 4.3 billion years ago
*Evidence:
Amphibolite rocks only
form 12 miles deep and they are 4.3
billion years old.
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*Event:
Oceans formed 4.3 billion
years ago
*Evidence:
Banded Iron formations
only form under water and they are
4.3 billion years old
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*Event:
Water came from space in
meteorites, drop by drop
*Evidence:
Salt in meteorites
contains water droplets, and the salt
is 4.5 billion years old
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*Event:
Amino acids, a building block
of life, came from space
*Evidence:
Amino acids were found
in meteorites 4.5 billion years old
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*Event:
The Earth’s atmosphere
changed from toxic to oxygen,
allowing advanced life to develop.
*Evidence:
3.5 billion year old
stromatolite fossils show that
cyanobacteria began to create
oxygen gas.
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