Geologic Time Early Earth - Colorado State （早期地质时期地球科罗拉多州立）.pdf
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ATS 150 Global Climate Change Climates of the Past
Geologic Time Early Earth
• Precambrian, • Formed by accretion ~ 4.7 billion years ago
and then • Solar “constant” was ~ 30% less than today
everything • Impact heating kept surface hot and sterile
else! • Very hostile
(It ’s always
down there)
• “Primary,
Secondary,
Tertiary”
• Fossils told
this story
copyright 2008 by Don Dixon
Early Life Rise of Oxygen
• Marine photosynthesis ozone!
1) Formation of Oceans
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