GEOLOGY

Detailed explanation-1: -If the oceanic crust reaches a deep sea trench, it sinks into the trench and is lost into the mantle. Scientists now know that the oldest crust is coldest and lies deepest in the ocean because it is less buoyant than the hot new crust. Seafloor spreading is the mechanism for Wegener’s drifting continents.

Detailed explanation-2: -The world’s oldest oceanic crust – around 340 million years old – lies at the bottom of the eastern Mediterranean Sea, according to a geologist in Israel.

Detailed explanation-3: -Matching magnetic lines of reversal along both sides of the ocean ridge also lends support to the theory of sea floor spreading. The subduction zones which form the deep sea trenches also support the theory of sea floor spreading.

Detailed explanation-4: -The oldest rocks of the oceanic crust are found in deep oceanic trenches far away from active, mid-ocean ridges. As the south Atlantic basin widens by seafloor spreading, Africa and South America are moving closer together. At times in the past, the polarity of Earth’s magnetic field has been reversed.

Detailed explanation-5: -The OLDEST band of rocks are found along the mid-ocean ridges while the YOUNGEST band of rocks are found far away from the ridge.