<P> The Mariana Trench is part of the Izu - Bonin - Mariana subduction system that forms the boundary between two tectonic plates . In this system , the western edge of one plate , the Pacific Plate , is subducted ( i.e. , thrust ) beneath the smaller Mariana Plate that lies to the west . Crustal material at the western edge of the Pacific Plate is some of the oldest oceanic crust on earth ( up to 170 million years old ) , and is therefore cooler and more dense ; hence its great height difference relative to the higher - riding ( and younger ) Mariana Plate . The deepest area at the plate boundary is the Mariana Trench proper . </P>
<P> The Mariana Trench is part of the Izu - Bonin - Mariana subduction system that forms the boundary between two tectonic plates . In this system , the western edge of one plate , the Pacific Plate , is subducted ( i.e. , thrust ) beneath the smaller Mariana Plate that lies to the west . Crustal material at the western edge of the Pacific Plate is some of the oldest oceanic crust on earth ( up to 170 million years old ) , and is therefore cooler and more dense ; hence its great height difference relative to the higher - riding ( and younger ) Mariana Plate . The deepest area at the plate boundary is the Mariana Trench proper . </P>
what is the mariana trench and what does it do with tectonic plates
what is the mariana trench and what does it do with tectonic plates
part of the Izu - Bonin - Mariana subduction system that forms the boundary between two tectonic plates
part of the Izu - Bonin - Mariana subduction system that forms the boundary between two tectonic plates