The shallow dipping slab subducting beneath Chile at an angle of about 10–15° causes a compressional stress on the back-arc region behind the Andes.[6] On the other extreme, the slab going down into the mantle at the Marianas subduction zone is so steep it is nearly vertical.[6] This is the perfect example of an oceanic back-arc basin experiencing extensional forces. The Oriente in Ecuador (the eastern part of the country covered by rainforest) is also a good example of an extensional back-arc basin, this time in a continental setting. The continental crust in this area east of the Andes has been stretched out and covered by layers of sediments.