Amazon Basin (sedimentary basin)

The Amazon Basin is a very large area where layers of sand, mud, and other materials have built up over millions of years. It covers about 620,000 square kilometres, or 240,000 square miles, near the middle and lower part of the Amazon River. This place is found south of the Guiana Shield and north of the Central Brazilian Shield.

This basin started forming on a rift, which is a place where the Earth's crust pulled apart, around 550 million years ago during a time called the Cambrian. Over time, it became a very important area for storing water and shaping the land around the Amazon River, one of the largest rivers in the world. It is a key part of understanding Earth's history and how rivers change the landscape.

Location

The Amazon Basin is south of the Guiana Shield and north of the Central Brazilian Shield. It is east of the Solimões Basin and west of the Marajó Basin. The basin goes from near Manaus to where the Xingu River joins the Amazon River. It is bordered by the Púrus Arch on the west and the Gurupá Arch on the east.

Evolution of the basin

The Amazon Basin formed from a rift called the Sub-Amazonal Rift. This rift began about 550 million years ago when continents came together. Later, parts of the rift became active again as the South Atlantic Ocean formed. The basin changed over time because of movements of the Earth's plates, including collisions and changes near the Andes Mountains.

Bauxite deposits

The Amazon Basin has large amounts of a special rock called bauxite. This rock is rich in aluminum. Scientists found these bauxite deposits about 70 years ago. This helped make Brazil an important country for producing and owning bauxite.