1 MAS 603: Geological Oceanography MAS 603: Geological Oceanography Lecture 1: Introductions; Lecture 1: Introductions; Geological Thinking Geological Thinking UNIVERSITY OF SOUTH ALABAMA Today Today’ s Agenda s Agenda A) Introductions • Syllabus (assessment etc.) • Additional subject material (student choice) • Introduction to geology and plate tectonics Today Today’ s Agenda s Agenda Syllabus Syllabus Syllabus Syllabus Syllabus Syllabus
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UNIVERSITY OF SOUTH ALABAMA Today’s Agenda...The Plate Tectonics Revolution Earth has a magnetic field (and it isn’t constant) The Plate Tectonics Revolution 1669 lava flow magnetic
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MAS 603: Geological OceanographyMAS 603: Geological Oceanography
1963-1968 J. Tuzo Wilson was the first to describe global tectonics in terms of rigid surface "plates“, and recognized ocean evolution (“Wilson Cycle”).
He characterized three basic plates boundaries
The Plate Tectonics Revolution1963-1968 J. Tuzo Wilson was the first to
describe global tectonics in terms of rigid surface "plates“, and recognized ocean evolution (“Wilson Cycle”).
He characterized three basic plates boundaries
The Plate Tectonics Revolution
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So how does it all work?
The Earth
Internal “guts”of the Earth
Internal “guts”of the Earth
Four Major “Geophysical” Layers
Internal “guts”of the Earth
Four Major “Geophysical” Layers1) The Crust (5-35 km thick; rigid rock)
Internal “guts”of the Earth
Four Major “Geophysical” Layers1) The Crust2) The Mantle (2865 km; rigid to ductile rock)
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Internal “guts”of the Earth
Four Major “Geophysical” Layers1) The Crust2) The Mantle3) The Outer Core (2200 km; liquid metal)
Internal “guts”of the Earth
Four Major “Geophysical” Layers1) The Crust2) The Mantle3) The Outer Core4) The Inner Core (1270 km; solid metal)
Heat exchange gives rise to Convection Currents
Asthenosphere
Cooler
Hotter
1928 - British geologist Arthur Holmes proposed that convection currents in the mantle could be moving things
More History of the Theory of Plate Tectonics
Cooler
Hotter
The Plate Tectonics Mechanism
Rising convection currents stress the rigid outer layer of the Earth.
The Plate Tectonics Mechanism
Crust
Mantle
Geophysical layers
Rising convection currents stress the rigid outer layer of the Earth. This layer consists of the crust and the outer most mantle
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The Plate Tectonics Mechanism
Crust
Mantle
Geophysical layers
Tectonic layers
Lithosphere:
Athenosphere:
Collectively, the rigid outer most part of the Earth (about 100 km thick) is called the Lithosphere
Cooler
Hotter
The Plate Tectonics Mechanism
It is postulated that the convection currents can eventually break up the lithosphere into separate plates
Tension
The Plate Tectonics Mechanism
Asthenosphere
Hence the term “plate tectonics” Divergent Plate Boundaries
Convergent Plate Boundaries
Transform Fault Plate Boundaries
San
And
reas
Fau
lt
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Hot Spots
Hot Spots
Next Week’s lecture1. New developments in plate tectonics