Late Quaternary Moraines in the Chimborazo Area, Ecuador

A relative sequence of late Quaternary glacier moraine stages is presented for the Rio Mocha valley on the eastern flanks of the Chimborazo-Carihuairazo massif, Ecuador. Three successively lower groups of moraines are distinguished by location, morphological characteristics, and depth of volcanic ash cover. The moraine groups are assigned to the Neoglacial, late glacial, and last glacial maximum stages. Radiocarbon analyses of two peat layers from a lake basin formerly ponded by the presumed late glacial moraines have given ages of 11,370 ± 60 yr BP (SRR-2582) and 10,650 ± 60 yr BP (SRR-2581). A rough calculation of the depression of the equilibrium line during the three moraine stages gives values of 50, 250, and 450 m.