Editing Amazon River (section)

=== Origins ===
{{main|Source of the Amazon River}}
[[File:Amazon origin at Mismi.jpg|thumb|left|upright|The Amazon was thought to originate from the Apacheta cliff in [[Arequipa]] at the [[Nevado Mismi]], marked only by a wooden cross.]]
[[File:The Source of the Amazon River.jpg|thumb|upright=1.3|Nevado Mismi, formerly considered to be the source of the Amazon]]
[[File:Río Marañón 03245.JPG|thumb|[[Marañón River]] in Peru]]

<!--see talk page re most distant source. 15 November 2015-->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,<ref name=Palkiewicz>{{cite web |url=http://www.palkiewicz.com/ekspedycje/index.php?p=zrodl_amaz |title=Source of the Amazon River Identificated (Jacek Palkiewicz) |publisher=Palkiewicz.com |date=19 November 1999 |access-date=13 February 2011 |url-status=live |archive-url=https://web.archive.org/web/20070312092613/http://www.palkiewicz.com/ekspedycje/index.php?p=zrodl_amaz |archive-date=12 March 2007}}</ref> 2001,<ref>{{cite magazine |url=http://news.nationalgeographic.com/news/2000/12/1221amazon.html |last=Smith |first=Donald |title=Explorers Pinpoint Source of the Amazon (National Geographic News) |magazine=National Geographic |date=21 December 2000 |access-date=15 July 2017 |archive-url=https://web.archive.org/web/20171101075405/https://news.nationalgeographic.com/news/2000/12/1221amazon.html |archive-date=1 November 2017}}</ref> 2007,<ref name=bbc-amazon>{{cite news |title=Amazon river 'longer than Nile' |work=BBC News |url=http://news.bbc.co.uk/2/hi/6759291.stm |access-date=3 August 2010 |date=16 June 2007 |url-status=live |archive-url=https://web.archive.org/web/20100926054938/http://news.bbc.co.uk/2/hi/6759291.stm |archive-date=26 September 2010 |df=dmy-all}}</ref> and 2008,<ref name=inpe>{{cite web |title=Studies from INPE indicate that the Amazon River is 140&nbsp;km longer than the Nile |publisher=Brazilian National Institute for Space Research |url=http://www.inpe.br/ingles/news/news_dest29.php |access-date=3 August 2010 |archive-url=https://web.archive.org/web/20110411011122/http://www.inpe.br/ingles/news/news_dest29.php |archive-date=11 April 2011}}</ref> where various authors identified the snowcapped {{cvt|5597|m|sp=us}} [[Nevado Mismi]] peak, located roughly {{cvt|160|km|sp=us}} west of [[Lake Titicaca]] and {{cvt|700|km|sp=us}} 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 [[Apurímac River|Río Apurímac]].

A 2014 study by Americans James Contos and Nicolas Tripcevich in ''[[Area (journal)|Area]]'', a peer-reviewed journal of the [[Royal Geographical Society]], however, identifies the most distant source of the Amazon as actually being in the [[Mantaro River|Río Mantaro]] drainage.<ref name="ContosTripcevich" /> A variety of methods were used to compare the lengths of the Mantaro river vs. the Apurímac river from their most distant source points to their confluence, showing the longer length of the Mantaro. Then distances from [[Lake Junin|Lago Junín]] to several potential source points in the uppermost Mantaro river were measured, which enabled them to determine that the Cordillera Rumi Cruz was the most distant source of water in the Mantaro basin (and therefore in the entire Amazon basin). The most accurate measurement method was direct GPS measurement obtained by kayak descent of each of the rivers from their source points to their confluence (performed by Contos). Obtaining these measurements was difficult given the [[International Scale of River Difficulty|class IV–V]] nature of each of these rivers, especially in their lower "Abyss" sections. Ultimately, they determined that the most distant point in the Mantaro drainage is nearly 80&nbsp;km farther upstream compared to Mt. Mismi in the Apurímac drainage, and thus the maximal length of the Amazon river is about 80&nbsp;km longer than previously thought. Contos continued downstream to the ocean and finished the first complete descent of the Amazon river from its newly identified source (finishing November 2012), a journey repeated by two groups after the news spread.<ref>{{cite web |url=http://blog.geographydirections.com/2014/04/03/redefining-the-upper-amazon-river |last=Contos |first=James (Rocky) |title=Redefining the Upper Amazon River |website=Geography Directions |date=3 April 2014 |access-date=15 July 2017 |url-status=live |archive-url=https://web.archive.org/web/20170312152411/https://blog.geographydirections.com/2014/04/03/redefining-the-upper-amazon-river/ |archive-date=12 March 2017}}</ref>

After about {{cvt|700|km|mi}}, the Apurímac then joins Río Mantaro to form the Ene, which joins the Perene to form the Tambo, which joins the [[Urubamba River]] to form the Ucayali. After the confluence of Apurímac and Ucayali, the river leaves Andean terrain and is surrounded by [[floodplain]]. From this point to the confluence of the Ucayali and the Marañón, some {{cvt|1600|km|sp=us}}, the forested banks are just above the water and are inundated long before the river attains its maximum flood stage.{{sfn|Church|1911|p=789}} The low river banks are interrupted by only a few hills, and the river enters the enormous [[Amazon rainforest]].