A Divergent plate boundary is a tectonic boundary where two plates are moving away from each other and new crust is forming from magma that rises to the Earth's surface between the two plates. The middle of the Red Sea and the mid-ocean ridge (running the length of the Atlantic Ocean) are divergent plate boundaries. Divergent boundaries are characterized by a rift in the surface of the earth along the midocean ridges that exist in all of the major ocean basins. The ridges are composed of volcanic mountains that erupt basalt onto the surface of the ocean and by that process create new oceanic crust. The almost constant eruption of basalt causes each side of the ridge to cool, crystallize, and move away from the ridge. Each pulse of basalt eruption causes the two sides of the rift zone to move a little farther apart. The rate of plate creation at divergent boundaries varies between about 2 and 6 centimeters per year. The creation of oceanic crust and movement away from the midocean ridges is called seafloor spreading. The most common processes occurring along divergent boundaries are volcanism and earthquakes. Many divergent boundaries are formed when a continent rifts apart and a midocean ridge forms between the two halves of the continent. Fault bounded rift valleys form at the edges of the continents that fill rapidly with relatively immature sediment and form rocks like arkosic sandstone and shale. These deposits, called red beds, are characteristic of the continental margins in divergent boundaries. Describe the Characteristic features found at convergent plate margins.
Convergent boundaries are boundaries at which crust is destroyed by the subduction of oceanic crust beneath continental crust or other oceanic crust. Convergent boundaries contain the broadest array of geologic activities. The movement of oceanic crust beneath another crustal plate results in heating of materials that are dragged down with the plate and eventual partial melting of the...
Please join StudyMode to read the full document