Glacier Inventory for the Northern Patagonia Icefield, Chile, and Variations 1944/45 to 1985/86

Abstract

The 28 outlet glaciers of the Northern Patagonia Icefield, Chile, with a total contiguous surface area of about 4200 km², were inventoried in a detailed statistical manner. The San Quintin and San Rafael glaciers, each with an area of about 760 km², are the two largest. Equilibrium lines are estimated at elevations of 900 to 1350 m, separating the total area into an accumulation area of 2578 km² and an ablation area of 1550 km².

The variation of 22 major glaciers between 1944/45 and 1985/86 was elucidated and an annual average rate of recession of up to 68 m yr^–1 was determined. One glacier showed almost no change at all, while the southwestern snout of the Reicher Glacier showed a net advance, although small. A decrease in accumulation in the icefield has caused this general recession. However, the individual variation was probably governed by one of or a combination of the following four factors: (1) orographic situation of the accumulation area, i.e., whether it is located on the leeward (eastern) or windward (western) side; (2) the relative height of the topographic threshold to the icefield surface elevation; (3) the perimeter length, although in a relative sense, of the wasting front of the glacier; and (4) the ratio of the ablation area to the accumulation area of the glacier.