earliest phase of Earth heating first seas thin atmosphere of H CO 2 H 2 O N 2 CO NH 3 CH 4 early bombardment Early Bombardment 2 phases Relative dating ID: 540855
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Slide1Slide2
Early Earth
…earliest phase of
Earth heating…
…first seas…
…thin atmosphere of
H, CO
2, H2O, N2, CO, NH3, CH4
…early bombardment…Slide3
Early Bombardment
2 phases?
Relative datingSlide4
Early Earth began to heat as the last extraterrestrial collisions subsided
Rock is a good insulator – stores heat
Collisions produced heat that was stored
Radioactivity
Gravitational contraction
Earth Developed
a Magma Sea4.5-4.0 billion years agoWhat is the physical consequence of melting a ball of rock with many different types of elements and compounds?Slide5
Temperature reached melting point
of iron
:
Liquid iron flowed inward
Friction raised temperature
Less dense compounds flowed
outward (SiO2 and others)
“Iron Catastrophe”
Planet became chemically
differentiatedSlide6
Fe/Ni
Fe/Mg
Increasing
Fe toward
core
Increasing
Si toward
surface
There are certain trends in Earths chemistry.
The crust is relatively depleted in Fe, Mg and enriched in Si, OSlide7
Effect of
chemical
differentiation
There are certain trends in Earths chemistry.
The crust is relatively depleted in Fe, Mg and enriched in Si, OSlide8
Earth’s magnetic field
emanates from the
core complex and
surrounds the planet.
Magnetism gained
from early nebula is
magnified by turbulentiron, nickel fluid of outer core.Magnetic field envelops
entire
planet
Polarity
+
-
tends to reverse and fluctuate with timeSlide9Slide10
Earth is probably not built of
uniform layers, it is likely mixed somewhat by convectionSlide11
MANTLE PLUMES
warm rock rises, cool rock descends
How will the lithosphere respond to a plume?Slide12
The continental rifting process
a
q
KkSlide13