CONCEPT OF PLATE TECTONICS

CONCEPT OF PLATE TECTONICS

       Plate tectonics is a scientific theory describing the large-scale motion of seven large plates and the movements of a large number of smaller plates of earth's lithosphere, since tectonic processes began on Earth between 3.3 and 3.5 billion years ago. 




THE HIMALAYAS
(Convergent plate boundary) 


       Continental crust is too buoyant to subduct. When two continental plates converge, they smash together and create mountains. The amazing Himalaya mountains are the result of this type of convergent plate boundary. 


ICE LAND
(Hotspot and divergent plate boundary) 


    The geology of iceland is unique and of particular interest of geologist Iceland lies on the divergent boundary between the Eurasian plate and the North American plate. It also lies above a hotspot, the Iceland plume. The plume is believed to have caused the formation of Iceland itself, the island first appearing over the ocean surface about 16 to 18 million years ago. 


HAWAII
(Hotspot) 

    The Hawaiian Islands were formed by a hotspot occurring in the middle of the Pacific plate. While the hotspot itself is fixed, the plate is moving. So, as the plate moved over the hotspot itself is fixed, the plate is moving. So, as the plate moved over the hot spot, the string of islands that makes up the Hawaiian Island chain were formed. 
     The Hawaiian Islands from an archipelago the extends over a vast area of the North Pacific Ocean. The archipelago is made up of 132 island, atolls, reef, shallow banks, shoals, and seamounts stretching over 1,500 miles from the island of Hawaii in the Southeast to kure Atoll in the Northwest. 


SAN ANDREAS FAULT
(Transform plate boundary)

 
    The San Andreas Fault is a transform boundary, which means the two plates are sliding alongside each other. The Western half of California is moving north because it is part of the Pacific plate, and the Eastern half of California is moving South because it is part of the North American plate. 


THE ANDES
(Convergent plate boundary) 


    The Andes were formed by tectonic activity whereby Earth is uplifted as one plate (oceanic crust) subducts under another plate(continental crust). To get such a high mountain chain in a subduction zone setting is unusual, which adds to the importance of trying to figure out when and how it happens. 


MID ATLANTIC RIDGE
(Divergent plate boundary)

    The Mid-Atlantic Ridge is known as a mid-ocean ridge, an underwater mountain system formed by plate tectonics. Like other ocean ridge system, the MAR developed as a consequence of the divergent motion between the Eurasian and North American and South American plates. 


EAST AFRICAN RIFT VALLEY
(Divergent plate boundary) 


    Million of years ago, the Arabian peninsula was connected to Africa. Seafloor spreading caused the Arabian and African plates to rift apart. The Indian Ocean flooded the rift valley between the continents, creating the red Sea. South of the red Sea Rift lies the massive, complex East African rift Valley. 


     




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