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24 Cards in this Set
- Front
- Back
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Earth chemical composition model
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crust, mantle, core
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Earth physical property model
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litosphere, asthenosphere, mesophere, outer core, inner core
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Hypothesis and theory
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continental drift, seafloor spreading, plate tectonics
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Continental drift
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1910s Alfred Wegener
Pangaea |
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Pangaea
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Laurasia (N) and Gondwana (S)
All land, unified super continent Fossils show similarity on two separated continents |
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Seafloor Spreading
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Harry Hess
Lack of mechanism for continental drift 1940s to early 1960s, WWII and ocean expedition increased knowledge of oceanography |
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Seafloor Spreading proposed idea
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Seafloor not a single static piece
Existence of mid-oceanic ridges Seafloor spreading along mid-oceanic ridges Continents "float over: spreading seafloor |
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Evidence
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Paleomagnetic data
dipolar magnetic field, magnetic field recorded by iron-bearing igneous rocks |
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Age of seafloor
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progressively younger toward the mid-oceanic ridge
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Thickness of sediments
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Thinner towards the ridge
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Plate Tectonics
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unified theory: putting it together
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lithosphere fragments
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plates composed of continents and/or ocean material
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Plates move...
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in relation to each other at varied rates
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Dynamic actions...
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concentrated along plate boundaries, no major tectonic movements within plates
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mechanism for plate tectonics
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earth interior convection
cool water on either side hot water pushing those circularly |
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Plate boundaries
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Divergent plate boundary, Convergent plate boundary, Transform plate boundary
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Divergent plate boundary
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-plates move away from each other
-extensional stress and shallow earthquakes -basaltic volcanism mid-oceanic ridges, continental rift valleys |
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Convergent plate boundary
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C-C boundary, O-O boundary, C-O boundary
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C-C boundary
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major mountain belts and shallow earthquakes
continental plate to continental plate |
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O-O boundary
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subduction zone, deep oceanic trench, volcanic island arc, earthquakes
Oceanic plate to oceanic plate |
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C-O boundary
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major mountain belts, subduction zone/oceanic trench, shallow to deep earthquakes
Continental plate to oceanic plate |
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Transform plate boundary
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plates slide past one another with shallow earthquakes and now volcanism
San Andreas fault |
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Hot spot
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volcanic centers with magma source from deep mantle, perhaps near the core-mantle boundary
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Significance of tectonic cycle
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global distribution of resources
global patterns of earthquakes and volcanic activites impact on the landscape and global climates geological foundation for development and hazard mitigation |
