Negro River, Amazonas, Brazil

$Undergraduate student Tiago Pereira Araújo making a fracture survey in silicified sandstone layers that occur in the Alter do Chão Aquifer, to assess the aquifer's vulnerability. The outcrop is located along the Negro River, a few kilometers northwest from Manaus, Amazonas, Brazil. Photo: Ingo Wahnfried$

Undergraduate student Tiago Pereira Araújo making a fracture survey in silicified sandstone layers that occur in the Alter do Chão Aquifer, to assess the aquifer’s vulnerability. The outcrop is located along the Negro River, a few kilometers northwest from Manaus, Amazonas, Brazil. Photo: Ingo Wahnfried