Chapter 9 - Glaciolacustrine Processes

Abstract

Glacial lakes are bodies of water that are influenced by the presence of glaciers. They are commonly divided into two main groups: ice-contact lakes which are characterized by the presence of glacier ice terminating in lake water and distal lakes that are somewhat distant from, but still influenced by, the presence of glaciers and/or ice sheets. Glacial lakes are common features around the margins of glaciers and ice sheets, and often evolve from ice-contact lakes into ice-distal lakes as glaciers and ice sheets margins retreat and become spatially separated from the lake. Ice-contact lakes are characterized by rapid deposition, high variability in sedimentary facies and deposition of ice-rafted debris. Sedimentary records from ice-contact lakes contain information about the dynamic behaviour of adjacent glaciers and ice sheets, and data on the pattern and timing of ice retreat. In contrast, ice-distal lakes are characterized by relatively low rates of sediment accumulation and less variability in sedimentary facies. Ice-distal lakes frequently record the transition from ice-contact deposition to deposition dominated by fine-grained sediments from turbidites and settling from suspension. These lakes have become important environmental archives for a range of postglacial environmental changes including changes in hydrology, terrestrial slope instability, seismic shaking, magnetism, and vegetation change.