Caldera-like Feature of 6-7 km Diameter Around the "Boiling River of the Amazon"

In 2011 Andrés Ruzo began studying the Shanay-timpishka, a boiling river in the Amazon . It is described as “a natural feature: a non-volcanic, geothermal feature flowing at anomalously high rates”, see this National Geographic interview . The non-volcanic claim was interesting to me… Apparently groundwater finds its way in deep-rooted faults in the Earth’s crust and is heated according to the…