This study employs sedimentological indices and lichenometric dating on the lichen species Plac opsis patagonica to investigate the nature and age of debris cones which have accumulated at the margins of the downwasting San Rafael Glacier in Chilean Patagonia. These cones appear to have accumulated by the resedimentation of glacigenic deposits by debris flows, with debris movement starting in the early 1980s. Cone activity follows a pattern of intense initial activity and sediment mobilisation followed by increased stability and colonization by vegetation. Three of the four cones had stabilized within 15 years of sediment movement initiation. These features may be seen as being conditioned by glacial activity with second order controls provided by the local climate and sediment supply. The cones have accumulated in a 'paraglacial' environment.
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