Transcript Evolution of Amazon Basin

Evolution of Amazon Basin
Stage 1
• 500 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
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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