Which geological process typically results in the formation of new oceanic crust?

The process that primarily leads to the formation of new oceanic crust is seafloor spreading. This phenomenon occurs at mid-ocean ridges, where tectonic plates are moving apart. As the plates separate, magma from the mantle rises to fill the gap, creating new crust as it cools and solidifies. This process continuously generates new oceanic crust at divergent boundaries, which are areas where two tectonic plates move away from each other.

In contrast, volcanism refers to the movement of magma to the Earth’s surface, which can contribute to crust formation in other contexts, such as on land or at hotspot volcanoes, but it is not the primary mechanism for forming oceanic crust. Subduction involves one tectonic plate being forced beneath another, leading to the destruction of crust rather than its formation. Metamorphism involves the alteration of existing rock rather than the creation of new crust. Thus, seafloor spreading uniquely characterizes the process through which fresh oceanic crust is generated at mid-ocean ridges.