Evolution of Amazon Basin

Stage Million Years Ago Gondwanaland splits into South America and Africa Pre-Cambrian rocks erode and material is transported by rivers where they were compressed into sandstone Inland lake forms which drains into the Pacific creating a build up of sediment at the Delta

Stage 2 90 Million Years Ago South America moves West away from Africa running into the Nazca Plate Nazca Plate subducted and forces sedimentary material deposited in Delta to rise – Creates fold mountains (Andes) North and East buckle to create a basin

Stage 3 10 Million Years Ago Amazon River changes directions and flows towards the Atlantic Volcanoes and magma aid in building up the Andes

Stage 4 2 Million Years Ago Ice Age Carves of sedimentary rock Much of the eroded material is washed down into the basin formed by the North and East buckling

Stage 5 Present Tributaries bring sediment to the Amazon Basin Upper regions of Andes erosion creates fast flowing river – Creates deep V-shaped valleys Amazon Basin develops large flood plains due to seasonal flooding Meandering occurs due to flat relief