Relative dating of Late Quaternary deposits using cluster and discriminant analysis, Audubon Cirque, Mt. Audubon, Colorado Front Range

Abstract

Holocene and Late Quaternary talus, lobate rock glaciers, and moraines within Audubon Cirque, Colorado Front Range, were assigned reltive ages using the following age‐dependent criteria: fresh‐weathered ratio, pitting, weathering rind development, angularity, and surface, oxidation of boulders, together with lichen cover and largest lichen diameter. Principal Component scores, yielding four major groups of deposits (relative age units C, R, E and V, from youngest to oldest). Tentative correlation with other Colorado Late Quaternary sequences suggests that unit C is of Gannett Peak age (100–300 years B. P.), unit R of Audubon age (950–1850 years B. P.) unit E of Early Neoglacial age (3000–5000 years B. P.), and unit V of Late Pinedale age (about 10,000 Years B. P.). Correlation is problematic due to differences in operationsl definitions of relative dating parametrs between workers, and because climatic and lithologic variations between areas may confound the date.