the process of forcing ocean crust into the mantle is called subduction.
the process of forcing ocean crust into the mantle is called subduction.
the process of forcing ocean crust into the mantle is called?
subduction
since then, earth has been forming secondary and tertiary crust. secondary crust forms at mid-ocean spreading centers, where partial-melting of the underlying mantle yields basaltic magmas and new ocean crust forms. this "ridge push" is one of the driving forces of plate tectonics, and it is constantly creating new ocean crust. that means that old crust must be destroyed somewhere, so, opposite a spreading center, there is usually a subduction zone: a trench where an ocean plate is being shoved back into the mantle. this constant process of creating new ocean crust and destroying old ocean crust means that the oldest ocean crust on earth today is only about 200 million years old.
crust (geology)
oceanic crust, which forms the bedrock of abyssal plains, is continuously being created at mid-ocean ridges (a type of divergent boundary) by a process known as decompression melting. plume-related decompression melting of solid mantle is responsible for creating ocean islands like the hawaiian islands, as well as the ocean crust at mid-ocean ridges. this phenomenon is also the most common explanation for flood basalts and oceanic plateaus (two types of large igneous provinces). decompression melting occurs when the upper mantle is partially melted into magma as it moves upwards under mid-ocean ridges. this upwelling magma then cools and solidifies by conduction and convection of heat to form new oceanic crust. accretion occurs as mantle is added to the growing edges of a tectonic plate, usually associated with seafloor spreading. the age of oceanic crust is therefore a function of distance from the mid-ocean ridge. the youngest oceanic crust is at the mid-ocean ridges, and it becomes progressively older, cooler and denser as it migrates outwards from the mid-ocean ridges as part of the process called mantle convection.
abyssal plain