San Francisco Pass it passes next to Maricunga's salt flat on the Nevado Tres Cruces National Park and Laguna Verde. The area is surrounded by volcanoes and high peaks as the Cerro Falso Azufre (), the volcano San Francisco (), the Incahuasi () and highest volcano in the world, Nevado Ojos del Salado (), among others. San Francisco Pass The San Francisco Pass is a pass over the Andes mountains which connects Argentina and Chile. The highest point of this pass is at AMSL. The pass is located at and connects the Argentine province of Catamarca with the Atacama Region in Chile. In
Ojos del Salado of the Nazca Plate beneath the South America Plate became increasingly shallower and this caused volcanism to shift from the Maricunga Belt to the Ojos del Salado region. The Paleozoic basement crops out only northwest of Nevado Tres Cruces. Other geologic units in the region are Oligocene sedimentary units and volcanic rocks ranging from Oligocene age to less than 1.5 million years old. The area is part of a tectonic boundary between a volcanically active region north of the boundary and a less volcanically active region south of the boundary, which is also characterized by geographical differences, e.g. the presence