Soils of Chilean Patagonia in Glacial and Periglacial Environments

Previous studies have shown that the area between the present Northern and Southern Patagonian Ice Fields (47 degrees S to 48 degrees S) was covered with ice during the Last Glacial Maximum (16000 BP). The ice retreat generated a typical glacial geomorphology with moraines, kettles, kame terraces, fluvioglacial terraces and fluvial terraces. Until now, there have been no detailed studies to determine the type of soils in the area. We described and classified one hundred and fifty pedons located in the Baker River Basin (47 degrees S) and the Pascua River Basin (48 degrees S), which we correlate with the respective geomorphology. The mean annual precipitation is 1000 mm for the Baker River study area and 2500 mm for the Pascua River Basin area, whereas the average annual temperature is 9 degrees C and 7 degrees C, respectively. Based on previous studies that described the glacial fluctuations of the Northern and Southern Ice Fields and considering the presence of a volcanic ash layer due to the major Holocene eruptions of the Hudson Volcano (6700 BP), tentative soil profile ages are proposed, and the geomorphologic and soil descriptions are presented. Soils are classified as Entisols, Inceptisols, and Histosols, reflecting weak pedogenetic development, and consistent with the landscape age and climatic conditions.