New oceanic lithosphere forms at DIVERGENT PLATE BOUNDARY.
The Correct Answer and Explanation is:
New oceanic lithosphere forms at a divergent plate boundary, a type of plate boundary where two tectonic plates move away from each other. This process occurs primarily at mid-ocean ridges, such as the Mid-Atlantic Ridge, where the Earth’s lithosphere is being pulled apart. As the plates separate, magma from the mantle rises to fill the gap. This molten rock solidifies upon cooling, forming new oceanic crust.
At divergent boundaries, the Earth’s crust experiences tensional forces, causing it to stretch and crack. The gap created by this stretching allows hot, partially molten mantle material to rise towards the surface. As it cools, it forms new oceanic lithosphere. This lithosphere is typically composed of basalt, a dense, dark rock. Over time, the newly formed lithosphere moves away from the ridge and is replaced by more magma as the plates continue to pull apart.
This process of seafloor spreading is a key component of plate tectonics. As the oceanic lithosphere moves away from the ridge, it begins to cool and becomes denser, eventually sinking into the Earth’s mantle at convergent boundaries where subduction occurs. The continuous formation of new lithosphere at divergent boundaries plays a crucial role in the recycling of the Earth’s crust and is responsible for the expansion of the ocean floor.
The evidence supporting this process includes symmetrical magnetic stripes found on either side of mid-ocean ridges. These stripes indicate reversals in the Earth’s magnetic field over time, providing a record of seafloor spreading. Additionally, scientists have measured the age of oceanic crust, finding it to be youngest near the ridges and progressively older as one moves farther away, further supporting the theory of seafloor spreading at divergent boundaries.
