Observations on the Quaternary Firn Line in Peru

Abstract

At lat. 7° S. the fern line was at about 3,500 m. during the Riss glaciation, at 3,650 m. during the Würm maximum and at 3,700 m. during a later stage (Würm II?). The moraines were deposited by equatorial-type glaciers from which there was relatively little melt water. At lat. 14° S., during the Riss glaciation, an important ice cap covered a 3,900–4,000 m. high plateau, the firn line being at about 3,950 m. The role of melt waters was important in the formation of the moraines, suggesting their deposition from tropical-type glaciers. From the evidence of periglacial gravels it appears that this southern region has not been glaciated since Riss times.