Contdrift_Lecture - Chapter 22: Continental Drift and Plate...

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Evidence for continental drift Shapes of landmasses Distribution of ancient fossils Isotopic ages; rock types and structures Apparent polar wander paths Sea-floor spreading magnetic anomalies sea-floor spreading hypothesis sediment thickness and age present-day motions from GPS heat flow and topography Plates boundaries: side and bottom interactions between adjacent plates Divergent boundaries (plates coming apart) East African Rift Chapter 22: Continental Drift and Plate Tectonics Next lecture: Finish chapter 22
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Evidence for continental drift Shapes of landmasses Distribution of ancient fossils Isotopic ages; rock types and structures Apparent polar wander paths Sea-floor spreading magnetic anomalies sea-floor spreading hypothesis sediment thickness and age present-day motions from GPS heat flow and topography Plates boundaries: side and bottom interactions between adjacent plates Divergent boundaries (plates coming apart) East African Rift Chapter 22: Continental Drift and Plate Tectonics Next lecture: Finish chapter 22
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The similarity of the shapes of the South American and African coastlines has been noted since at least 1596. Here is one fanciful version of the idea published in 1858. The idea was not considered a serious scientific hypothesis until 1912. http://pubs.usgs.gov/gip/dynamic/continents.html
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Alfred Lothar Wegner Alfred Wegner was the first to seek out and compile additional geological and paleontological evidence to support the idea of “continental drift.” http://pubs.usgs.gov/gip/dynamic/continents.html
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This world bathymetric map, published in 1914, shows the continental shelves, shallow areas offshore from many continents. Wegener realized that the place to match was the shelves, not the shorelines. The rough outlines of the Mid-Atlantic Ridge system are also coming into rough view www.photolib.noaa.gov
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South America fits against Africa, and North America fits against Africa and Europe. Small gaps or overlaps can be accounted for by special explanations. South America Africa Europe North America
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Evidence for continental drift Shapes of landmasses Distribution of ancient fossils Isotopic ages; rock types and structures Apparent polar wander paths Sea-floor spreading magnetic anomalies sea-floor spreading hypothesis sediment thickness and age present-day motions from GPS heat flow and topography Plates boundaries: side and bottom interactions between adjacent plates Divergent boundaries (plates coming apart) East African Rift Chapter 22: Continental Drift and Plate Tectonics Next lecture: Finish chapter 22
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Fossils of Lystrosaurus , a late Paleozoic to early Mesozoic mammal- like reptile about the size of a pig, are found in continents that are widely dispersed today, including Antarctica, South Africa, and Asia (India, Russia, China, Mongolia).
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This note was uploaded on 09/14/2009 for the course GEO 401 taught by Professor Lassiter during the Spring '08 term at University of Texas at Austin.

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Contdrift_Lecture - Chapter 22: Continental Drift and Plate...

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