Do ice-dam rupture events leave a distinctive signature in proglacial lake sediments?

Abstract

Lake sediment provides a valuable record of past environmental change. However, the controls on sedimentation in proglacial lakes and their relation to glacier retreat remain poorly understood. In this study we analyze glaciolacustrine sediment production and deposition in Canal de los Témpanos, Lago Argentino, Argentine Patagonia. We associate temporal changes in the sedimentologic and geochemical characteristics analyzed from Lago Argentino cores with Late Holocene fluctuations of the Perito Moreno and Ameghino glaciers. We show that the dominant sediment source at our study site switched from Ameghino to Perito Moreno Glacier after the recession of Ameghino Glacier and the formation of the marginal ice-contact lake into which it currently calves. Spectacular ice-dam rupture events generated by Perito Moreno Glacier redistribute large volumes of water through the lake system but do not leave a significant sedimentary signature. Our results demonstrate that a detailed analysis of sedimentologic, petrophysical, and geochemical changes in lake cores can provide insight into regional glacial dynamics and sedimentary processes even in complex systems with multiple competing glacial sources and that changing glacier geometries during retreat can provide insights into the provenience of the sediments.