How is new crust created in Divergent Boundary
Answer (1)
Answer:New crust is created at divergent boundaries through a process called seafloor spreading. This occurs when tectonic plates move apart, creating a gap that is filled by magma rising from the Earth's mantle. Here's a detailed explanation: 1. Plate Movement and Rift Formation: - At divergent boundaries, tectonic plates are pulling away from each other.- This pulling force causes the lithosphere (the rigid outer layer of the Earth) to stretch and thin.- As the lithosphere thins, it becomes less dense and rises, creating a rift valley in the ocean floor or a rift valley on land. [2] 2. Magma Upwelling: - The thinning of the lithosphere reduces pressure on the underlying asthenosphere (the partially molten layer beneath the lithosphere).- This reduced pressure allows the asthenosphere to partially melt, generating magma. [1]- The magma, being less dense than the surrounding rock, rises buoyantly towards the surface, filling the gap created by the diverging plates. [1] 3. Crust Formation and Cooling: - As the magma reaches the surface, it erupts as lava flows, creating new oceanic crust. [1]- This lava cools and solidifies, forming basaltic rocks that are characteristic of oceanic crust. [1]- The process of magma rising and solidifying continues, pushing the newly formed crust away from the rift, creating a mid-ocean ridge. [2] 4. Features of Divergent Boundaries: - Mid-ocean ridges: These are underwater mountain ranges that form along divergent boundaries in the ocean. [2]- Rift valleys: These are deep valleys that form on land where continents are pulling apart. [2]- Volcanic activity: Divergent boundaries are characterized by volcanic activity, as magma rises to the surface. [1]- Shallow earthquakes: Earthquakes occur as the crust breaks and shifts during the process of seafloor spreading. [3] 5. Importance of Seafloor Spreading: - Seafloor spreading is a fundamental process in plate tectonics, driving the movement of continents and the formation of new ocean basins. [5]- It provides evidence for the theory of plate tectonics, as the age of the oceanic crust increases with distance from mid-ocean ridges. [5] In summary, new crust is created at divergent boundaries through the process of seafloor spreading, where magma rises from the mantle to fill the gap created by the diverging plates, cools, and solidifies to form new oceanic crust.
