Glacier-rock glacier relationships as climatic indicators during the late Quaternary in the Cordillera Ampato, Western Cordillera of southern Peru

Mapping of glacial and periglacial features along a 15 km long, north-south trending ridge at the eastern end of the Cordillera Ampato (Fig. 1) has been carried out using aerial photograph interpretation. Over the length of the ridge a distinct change in features from moraines and small rock glaciers in the north to large rock glaciers and a lack of moraines in the south can be observed. It is suggested that this feature change reflects a steep precipitation gradient during the Pleistocene. Comparison with geomorphological mapping — both in the field and from air photographs — in other areas of the Cordillera Ampato and further west shows that this feature change is unique and that its location at the eastern end of the Cordillera is in good agreement with present-day precipitation distribution. This indicates that the general precipitation pattern, and thus the general circulation pattern, during the Pleistocene was very similar to that today.