Sumatra Trench Sumatra Trench The Sumatra Trench belongs to the Sunda Trench or Java Trench. The Sunda subduction zone (called also: the Sumatra-Andaman subduction zone) is located in the east part of Indian Ocean, and is about 300 km from the southwest coast of Sumatra and Java islands. It extends over 5000 km long, starting from Burma in the northwest and ending at Sumba Island in the southeast. The Java trench was generated by the oblique subduction of the Indo-Australian Plate into the Sunda plate at a rate of 61mm/y (in the south) and 51mm/y (in the north). The oceanic crust being
Chapada Diamantina 25 km wide and exposes the sedimentary rocks of the Paraguaçu group. At the contact there are two different rock groups exposed one being the Chapada Diamantina and the Paraguaçu, with the Chapada Diamantina overlaying the Paraguaçu group. The two rock groups not only in elasticity but in composition as well. The Chapada Diamantina is composed primarily of sandstone, pelites and diamond bearing conglomerates. The Paraguaçu is composed of fine-grained sandstones, siltstones and argillites. The rocks of the Paraguaçu are softer and therefore more susceptible to weathering and folding. It is the folds in the Paraguaçu that allows for the