GEOL 1110 Lecture Notes - Lecture 3: Hypocenter, Himalayas, East Pacific Rise
3 Jul 2018
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Chapter 2: Plate tectonics
Plate Tectonics
Continental Drift and Paleomagnetism
oSeafloor spreading
Plate Tectonics
oDivergent Plate Boundaries
oConvergent plate boundaries
oTransforms plate boundaries
Continental Drift: Precursor
1912 – Alfred Wegner hypothesizes that all of the continents once fit together
and have drifted apart
oThere’s lots of evidence
A lot in glaciers pick up rocks and make striations (scratches
from rocks on one another), these can be tracked and studied
Coal swamps same types of coal found in two different locations
on different continents
Salt deposits
Desert sand
Same species found on different continents across oceans
Mountain belts/chains in different areas now, all with the same type
of rocks
On multiple times there were a type of “Pangea,” all of which were configured
differently
Pangea
A theory based upon the fit of continents and mountain chains and fossil records
oAlfred Wegener
oBreak up of Pangea
Evidence
oPaleomagnetism
The magnetism in ancient rocks
Earth has a magnetic field with polarity
The iron in rocks acts like a compass when solidifying
Provides evidence of orientation of magnetic pole
Magma is Lava when it touches air or water, if it has iron in it
turns black and has a certain polarity according to the
magnetic pole orientation
oPolar Wandering
The magnetic poles wander around the geographic north pole
Differences in magnetic alignment of rocks
Subtle differences
Magnetic poles get stronger and weaker over time
find more resources at oneclass.com
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Document Summary
Continental drift and paleomagnetism: seafloor spreading. Plate tectonics: divergent plate boundaries, convergent plate boundaries, transforms plate boundaries. 1912 alfred wegner hypothesizes that all of the continents once fit together and have drifted apart: there"s lots of evidence. A lot in glaciers pick up rocks and make striations (scratches from rocks on one another), these can be tracked and studied. Coal swamps same types of coal found in two different locations on different continents. Same species found on different continents across oceans. Mountain belts/chains in different areas now, all with the same type of rocks. On multiple times there were a type of pangea, all of which were configured differently. A theory based upon the fit of continents and mountain chains and fossil records: alfred wegener, break up of pangea. Earth has a magnetic field with polarity. The iron in rocks acts like a compass when solidifying. Provides evidence of orientation of magnetic pole.
