.........> VOLCANOES ...> GLACIERS ..> RISCOS NEGROS ......> RISCOS BLANCOS

Climatic fluctuations of great intensity caused temperature decreases and glaciations. The region was covered by 40 meter thick ice mantles, which buried the lower formations. The tuff of “Riscos Negros” was buried under the ice. The ignimbrite of “Riscos Blancos” erected like Nunataks, peaks that emerged from the surface of the ice mantle.