Alluvial gold mining

The Andes Mountains are rich in minerals, including gold. Over millions of years, erosion has carried gold down the eastern slope of the Andes and deposited it along river beds, leaving larger nuggets upstream and finer grains downstream. The tropical rivers have...
Andes mountains

Andes mountains

The uplift of the Andes mountains over millions of years has been due to a combination of plate tectonics and volcanism. Tectonic plates are sections of the earth’s crust that are in motion. Where they collide, they cause earthquakes and volcanoes and form...

Deforestation

More people moving to Amazonia usually mean more deforestation. Regionwide, most deforestation is due to clearing for agriculture, but in some areas of Madre de Dios, deforestation for alluvial gold mining has surpassed agriculture as the primary cause. Logging –...
Pacific coast

Pacific coast

Peru’s coast is a long strip of desert cut in more than 50 places by seasonal rivers that flow from the Andes to the Pacific Ocean. But the coast has not always been arid. After South America broke away from Africa and the rest of Gondwana, the west coast was...

Population pressure

While three-quarters of the residents of Amazonia live in Brazil, the population has been growing in the Amazonian region of all the countries that share the basin. Population density in Amazonia has increased in the past two decades, from 3.4 inhabitants per square...