early earth
DESCRIPTION
Early Earth. …early bombardment…. …earliest phase of Earth heating…. …thin atmosphere of H, CO 2 , H 2 O, N 2 , CO, NH 3 , CH 4. …first seas…. Early Bombardment 2 phases?. Relative dating. Earth Developed a Magma Sea 4.5-4.0 billion years ago. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Early Earth](https://reader036.vdocuments.us/reader036/viewer/2022062520/56815f4d550346895dce2b84/html5/thumbnails/1.jpg)
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Early Earth…earliest phase of Earth heating…
…first seas…
…thin atmosphere of H, CO2, H2O, N2, CO, NH3, CH4
…early bombardment…
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Early Bombardment
2 phases?
Relative dating
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Early Earth began to heat as the last extraterrestrial collisions subsided1. Rock is a good insulator – stores heat2. Collisions produced heat that was stored3. Radioactivity4. Gravitational contraction
Earth Developed a Magma Sea4.5-4.0 billion years ago
What is the physical consequence of melting a ball of rock with many different types of elements and compounds?
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Temperature reached melting point of iron:
• Liquid iron flowed inward• Friction raised temperature
• Less dense compounds flowedoutward (SiO2 and others)
“Iron Catastrophe”
Planet became chemicallydifferentiated
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Fe/Ni
Fe/Mg
IncreasingFe toward
core
IncreasingSi towardsurface
There are certain trends in Earths chemistry.The crust is relatively depleted in Fe, Mg and enriched in Si, O
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Effect ofchemical differentiation
There are certain trends in Earths chemistry.The crust is relatively depleted in Fe, Mg and enriched in Si, O
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Earth’s magnetic fieldemanates from the core complex and surrounds the planet.
Magnetism gained from early nebula ismagnified by turbulentiron, nickel fluid of outer core.
Magnetic field envelops entire planet
Polarity + - tends to reverse
and fluctuate with time
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Earth is probably not built ofuniform layers, it is likely mixed
somewhat by convection
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MANTLE PLUMES warm rock rises,
cool rock descends
How will the lithosphere
respond to a plume?
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The continental
rifting process
a
q
Kk
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