Volcano Learning ZoneVolcano Learning Zone

Great for School work

Back Arc Basin 

Volcano Learning zone > Volcano Glossary

Subduction Zone and Back Arc Basin Wiki GNU Back Arc basins are an elongate zones of extension behind the arc associated with a subduction zone. As the the oceanic crust is subducted the trench pulls or rolls back away from the overlying plate- trench rollback. The extension allows basalts to erupt in a a similar way to mid ocean ridge basalt the main difference being that the basalts are have a higher water content derived from the loss of fluids from the mantle wedge. Spreading rates vary from 1-2cm / year to as much as 15cm/year.