Earth science Glaciers shield mountain tops: Glaciers frozen to bedrock may have protected the southernmost Andes from erosion, providing an explanation for the mountains' topography and fresh constraints on possible links between climate and tectonics.
Résumé
Most geologists would agree that mountain glaciers, which appeared some 3 million to 5 million years ago in response to Earth's slowly cooling climate, are responsible for erosionally shaping most mountains into their jagged present-day morphology. However, an extensive data set collected by Thomson and co-authors (page 313 of this issue 1) provides evidence that glaciers have protected rather than eroded the high-relief regions of southern Patagonia, which has led to a widening of the mountain belt during these geologically recent glaciations. This evidence supports the theoretical concept that climate, through erosion, or lack of it, affects the shape and dynamics of mountain belts.