LEcture 1 notes
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EESA06H3- Week 1
Readings: Chapters 1 & 2
Quizzes- done 8am-10pm
-“Earth History”- application of plate tectonic theory to the ancient past
-Planet is 4.5 billion years old.
-Oceans have come and gone, continents have migrated and life has evolved
-Plate tectonics—broken down into couple of large plates, which are mobile
-Geology- the study of what the planet looked like in the past
-We configured the surface of the planted, anthropogenic uses have caused
-Climate change—in a sort time scale due to global warming
-Paleo- geographic—important because, it is an important indicator of climate, resources and such
How planet earth works and the plate tectonic ‘Revolution’
Key Aspects to Read up on:
-Formation of planet earth 4,500 million years before present ‘continental drift’ and supercontinent
e.g. ‘Pangea’ 1912
-Sea Floor Spreading; 1960 (Harold Hess)
-‘Wander Paths’ for continents; 1965
-Magnetic ‘Stripes’ on the ocean floor; 1965 (Fred Vine)
-Mid-ocean ridges and hot spots; 1965 (Tuzo Wilson)
-‘Plate Tectonics’: 1967 (Tuzo Wilson)
-1600s—idea posted where continents fit like a puzzle, and that all continents were formed together.
-Continental Drift –Formal idea was posted 1912—Pangea- idea rejected by most people, too
hypothetical, in which there was no mechanism to see what moved the continents around.
-1960 scientists started mapping oceans, which cover 1970s.
-It was discovered through geophysical tools—ocean floor is not flat (most ocean floors had mountain
chains along their middle part)
-Higher mountains up to sea level lead to islands
-It was realized later that mountains under water were actually volcanoes
-“Sea-floor spreading” –continuous volcanic activity, adding material that replaces older material on
-Because of Sea Floor spreading, the Atlantic Ocean is widening
-Paleo-Magnetism- was actual proof that the continents had moved around.
-Lava cooling and ion particles become fixed and are not able to rotate anymore.
-Compass needles point to magnetic north.
-Ion particles get shifted and no longer point to the magnetic north
-Magnetic Stripes on the Ocean Floor—idea that magnetic poles can change (north can become south)
—known as magnetic reversal
-Earth’s mantle is unstable, change in clarity of magnetic field
-Magnetomitor- measures weather magnetic particles are related to north magnetic pole or south
-It was identified that there were stripes, bands of alternating polarity
-“Magnetic Stripes”—related to seafloor spreading, new magma pushes apart all rocks.
-Sea floor records changes –proved the concept of seafloor spreading
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