The Amazon River Basin
The greatest river system on Earth by discharge, carrying 20% of global river flow through the world’s largest equatorial rainforest.
Hydrological Influence & Ancient Statecraft
Discharging approximately 209,000 cubic meters of water per second into the Atlantic Ocean—more than the next seven largest rivers combined—the Amazon basin represents the pinnacle of global hydrology. Emerging from Andean glaciers, the river meanders through dense tropical rainforests that were home to sophisticated pre-Columbian urban settlements utilizing anthropogenic fertile dark earth (terra preta).
Agricultural Surplus & Flood Pulse Ecology
Intensive agroforestry, manioc cultivation, and terra preta anthrosols sustaining dense indigenous riverine chiefdoms.
Hydrological Anatomy
- ✓Represents 20% of total global riverine discharge into world oceans
- ✓Basin encompasses over 7 million square kilometers across eight South American nations
- ✓Famous "Meeting of the Waters" confluence where black acidic Rio Negro meets sandy Rio Solimões
- ✓No bridges span the entire width of the main Amazon trunk
About the Amazon River
The Amazon River in South America is the largest river in the world by discharge volume of water, and the second-longest or longest river system in the world, a title which is disputed with the Nile.
For nearly a century, the headwaters of the Apurímac River on Nevado Mismi in Peru had been considered the Amazon basin's most distant source, until a 2014 study found the farthest source to be the headwaters of the Mantaro River on the Cordillera Rumi Cruz in Peru. The Mantaro and Apurímac rivers join, and with other tributaries form the Ucayali River, which in turn meets the Marañón River upstream of Iquitos, Peru, forming what countries other than Brazil consider to be the main stem of the Amazon. Brazilians call this section the Solimões River above its confluence with the Rio Negro forming what Brazilians call the Amazon at the Meeting of Waters (Portuguese: Encontro das Águas) at Manaus, the largest city on the river.
Encyclopedic summary adapted from Wikipedia: Amazon River (CC BY-SA 4.0).
Amazon River in Depth
Course
The most distant source of the Amazon was thought to be in the Apurímac river drainage for nearly a century. Such studies continued to be published even as recently as 1996, 2001, 2007, and 2008, where various authors identified the snowcapped 5,597 m (18,363 ft) Nevado Mismi peak, located roughly 160 km (99 mi) west of Lake Titicaca and 700 km (430 mi) southeast of Lima, as the most distant source of the river. From that point, Quebrada Carhuasanta emerges from Nevado Mismi, joins Quebrada Apacheta and soon forms Río Lloqueta which becomes Río Hornillos and eventually joins the Río Apurímac.
History
Geological studies suggest that for millions of years, the Amazon River flowed in the opposite direction – from east to west. Eventually the Andes Mountains formed, blocking its flow to the Pacific Ocean and causing it to switch directions to its current mouth in the Atlantic Ocean.
During what many archaeologists called the formative stage, Amazonian societies were deeply involved in the emergence of South America's highland agrarian systems. The trade with Andean civilizations in the terrains of the headwaters in the Andes formed an essential contribution to the social and religious development of higher-altitude civilizations like the Muisca and Incas. Early human settlements were typically based on low-lying hills or mounds.
Geology
The Amazon River originated as a transcontinental river in the Miocene epoch between 11.8 million and 11.3 million years ago and took its present shape approximately 2.4 million years ago in the Early Pleistocene.
The proto-Amazon during the Cretaceous flowed west, as part of a proto-Amazon-Congo river system, from the interior of present-day Africa when the continents were connected, forming western Gondwana. 80 million years ago, the two continents split. Fifteen million years ago, the main tectonic uplift phase of the Andean chain started. This tectonic movement is caused by the subduction of the Nazca Plate underneath the South American Plate.
Sections adapted from Wikipedia: Amazon River (CC BY-SA 4.0).
Amazon River: Key Facts
| Average discharge | 209,000 m³/s |
|---|---|
| Drainage system | Amazon basin |
| Tributaries | Madeira River, Tapajós River, Xingu River, Rio Negro, Japurá River, Napo River, Putumayo River, Preto da Eva River |
Facts from Wikidata Q3783 (CC0).
Amazon River: Quick Answers
- Which countries does the Amazon River flow through?
- The mapped course of the Amazon River runs through or along Peru, Colombia and Brazil.
- Where does the Amazon River begin and end?
- Source: Río Apurímac / Nevado Mismi, Peruvian Andes. Mouth: Atlantic Ocean (Marajó Delta, Brazil).
- How long is the Amazon River?
- About 6,400 km (3,977 miles), draining a basin of about 7,050,000 km².
- Which civilizations grew up along the Amazon River?
- Among them: Marajoara Culture, Terra Preta Indigenous Societies and Kuhikugu Complex.
Countries Along the River
The main stream from source to mouth, then any country only a tributary or delta branch reaches.