SEA FLOOR SPREADING
Researchers in ethopia witnessing the birth of new ocean from the underneath of African landmass .they identified 60km long stretch with width of 8m since 2005,i.e., this process of splitting african plate is increasing .within 10million years somalian ethopian region will be separated from main africa by new ocean .presently, many volcanic activity is undergoing beneath the East African Rift Valleys .This process of ocean formation is explained by seafloor spreading mechanism .
According to plate tectonic theory, at the divergence centre ,plates moves away from each other and mantle convection cells pushes the molten magma towards the surface. in the process of rise of magma first, the plates becomes thinner , rocks and blocks under tensional force splits/break forming the rift valleys/grabben. With the passing time, more magma rises further deepining the riftvalleys and thinning the plates resulting into volcanic basaltic lava reaching the surface .thus,cooling and solidifing the magma in the floor of riftvalleys start forming new basaltic oceanic crust. Even, at the divergence centre magma cools and solidifies forming long under water mountain chain called as mid-oceanic ridges .
Researchers in ethopia witnessing the birth of new ocean from the underneath of African landmass .they identified 60km long stretch with width of 8m since 2005,i.e., this process of splitting african plate is increasing .within 10million years somalian ethopian region will be separated from main africa by new ocean .presently, many volcanic activity is undergoing beneath the East African Rift Valleys .This process of ocean formation is explained by seafloor spreading mechanism .
According to plate tectonic theory, at the divergence centre ,plates moves away from each other and mantle convection cells pushes the molten magma towards the surface. in the process of rise of magma first, the plates becomes thinner , rocks and blocks under tensional force splits/break forming the rift valleys/grabben. With the passing time, more magma rises further deepining the riftvalleys and thinning the plates resulting into volcanic basaltic lava reaching the surface .thus,cooling and solidifing the magma in the floor of riftvalleys start forming new basaltic oceanic crust. Even, at the divergence centre magma cools and solidifies forming long under water mountain chain called as mid-oceanic ridges .
In 1960, Harry Hess gave his theory of sea floor spreading after his research in mid Atlantic ocean. According to him ,from midoceanic ridges new magma seperates the old rock pushing away from each others and replaced by new rocks, these new basatic rocks are denser and lower than other and later on these lower areas filled with water forming seas and oceans .for example atantic ,indian and south eastern pacific ocean is spreading see the diagram below .
Several types of evidence supported Hess’s theory of sea-floor spreading: eruptions of molten material, magnetic stripes in the rock of the ocean floor, and the ages of the rocks themselves
Describe the seafloor spreading phenomena along with paleomagnetic studies evidence
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