There are always exceptions to the rule, and this boiling Amazonian river is undoubtedly an exception to our current understanding of the Amazon Rainforest. Andrés Ruzo, a PhD candidate in geophysics at SMU, has spent the last several years studying a very peculiar phenomenon in the Amazon Rainforest of Peru, a boiling river. From a childhood legend shrouded in myth and skepticism to the topic of his dissertation, this river has carved a path through Andrés' life and the geophysical community.
Boiling or near-boiling rivers do exist throughout the Earth, however they have always been associated with nearby volcanoes. We see fumaroles in Yellowstone emit water as hot as 280°F from meteoric water deep inside Earth's crust coming into contact with heated rocks. However, the nearest active volcano to the aforementioned boiling river of the Amazon is more than 400 miles away. This presents a question to geoscientists as to how a vast amount of water can be heated with no nearby apparent heat source, i.e. an active volcano.
Shanay-timpishka - boiled with the heat of the sun
The boiling river's local name is Shanay-timpishka, which translates to the river that is boiled with the heat of the sun. Local shamans believe that the boiling water is birthed by Yucamama, a giant serpent spirit known as the "Mother of the Waters." The river is shrouded in stories and legendary across Peru, however, this is the first time the source of heat has been studied by outside scientists. Andrés, after meeting with the local shaman, was granted the ability to study the mythical river. However, the shaman had one condition, that he pour out the river's waters after finishing his studies.
I had received the shaman's blessing to study the river, on the condition that after I take the water samples and analyze them in my lab, wherever I was in the world, I pour the waters back into the ground so that, as the shaman said, the waters could find their way back home. - Andrés Ruzo
This river, the width of a 2-lane road, is heated to an average of 186ºF across a 4-mile long stretch. Imagine the immense heat required to maintain such a large volume of water at near-boiling temperatures. The near-boiling temperatures cook small animals in seconds, littering the riverbed and slopes with cooked remains of unfortunate animals.
So where, if not volcanism, does the heat come from? The answer lies in the geothermal gradient of the Earth. As you may recall in geology class, the Earth heats up as you get deeper into the crust, mantle, and core. This is partly a combination of residual heating from initial planetary accretion billions of years ago, radioactive decay, and several other smaller heat sources.
The average global geothermal gradient away from active volcanoes and tectonic plate boundaries is 25 °C per km of depth into the crust. Using a back-of-the-envelope calculation with the assumption that the average surface temperature in the Amazon is 80ºF and a typical geothermal gradient, water would have to migrate 1.37 km or 0.85 miles into the Earth to be heated to 186ºF. This likely underestimates the depth fluids would have to migrate given natural cooling during the water's migration to the surface and temperature mixing from surface waters. However, we can assume that meteoric waters had to travel at a minimum of 1.4 km into Earth's crust.
The theory is that meteoric water falls onto the surface of the Amazon Rainforest and finds deep-rooted faults where it travels down into the crust. The water is thus heated in accordance with the geothermal gradient. It is then likely fed to the surface of the Earth through fault-fed hot springs that act to heat up the river through these 4 miles.
A resource to be protected
After years of rapid deforestation and urbanization of the nearby rainforest, Andrés Ruzo decided to launch the Boiling River Project as a means to protect the river and its nearby ecosystem. Mr. Ruzo's goal is to protect the native Amazonian communities, the sacred boiling river, and the geological significance of this site. The nonprofit organization was recently launched along with The Boiling River: Adventure and Discovery in the Amazon. The region is in danger of logging companies that increasingly destroy the Amazon rainforest to make room for grazing grasslands for cattle.
There remains so much to explore. We live in an incredible world. So go out. Be curious. Because we do live in a world where shamans still sing to the spirits of the jungle, where rivers do boil, and where legends do come to life.
Forbes/EM
