-
Antonio Pellegrini
Antonio Pellegrini showed how Africa and South America might have once been connected but got seperated over time by using maps. He also noticed how similiar fossils were in North America and Europe and thought that both continents were joined at one time. *http://library.thinkquest.org/3669/3669/history.html
*Google images -
Continental Drift (Alfred Wegener)
Alfred Wegener was a German scientist who proposed the hypothesis of Continental Drift. According to Wegener's hypothesis of continental drift, the continents had once been joined to form a single supercontinent, called Pangaea. Eventually they drfited apart. *Prentice Hall Earth Science Book
*Google Images -
Convection Currents (Arthur Holmes)
Arthur Holmes believed he could provide a mechanism that supported Wegener's hypotheisis. It was convection currents. Currents of heat and thermal expansion in the Earth's mantle, he suggested, could force the continents toward or away from one another, creating new ocean floor and building mountain ranges. *http://www.pbs.org/wgbh/aso/databank/entries/boholm.html
*Google Images -
Volcanic Island Arc
When 2 oceanic slabs converge, one goes beneath the other. This causes volcanic activity. The volcanoes form on the ocean floor. If this process continues, eventually it will build a chain of volcanic structures that become islands. This new land consisting of an arc-shaped chain of volcanic islands is called a volcanic island arc. *Prentice Hall Earth Science Book
*Google Images -
Sea-Floor Spreading (Harry Hess)
Harry Hess created the the hypothesis of sea-floor spreading. In the process of sea-floor spreading, new ocean floor forms along Earth's mid ocean ridges, slowly moves outward across ocean basins, and finally sinks back into the mantle beneath deep ocean trenches. *Prentice Hall Earth Science Book
*Google Images -
Hotspots
Hotspots are locataed at the edges of plates. Hotspots are situated places within the mantle or oceanic lithosphere. There rocks melt to form magma. A chain of volcanoes is built, some that may rise above sea level like the Hawaii Islands. Hot Spots explain why volcanoes form in other spots on the plates instead of at plate boundaries. *http://pubs.usgs.gov/gip/dynamic/hotspots.html
*Google Images -
Theory of Plate Tectonics (J. Tuzo Wilson)
In the theory of plate tectonics, Earth's lithospheric plates move slowly relative to each other, driven by convection currents in the mantle. *Prentice Hall Earth Science Book
*Google Images
