Rock glacier

About: Rock glacier is a research topic. Over the lifetime, 1723 publications have been published within this topic receiving 56467 citations.

Glaciers and glaciation.

Abstract: Glaciers and Glaciation is the classic textbook for all students of glaciation. Stimulating and accessible, it has established a reputation as a comprehensive and essential resource. In this new edition, the text, references, and illustrations have been thoroughly updated to give today's reader an up-to-the minute overview of the nature, origin, and behavior of glaciers and the geological and geomorphological evidence for their past history on earth. The first part of the book investigates the processes involved in forming glacier ice, the nature of glacier/climate relationships, the mechanisms of glacier flow, and the interactions of glaciers with other natural systems such as rivers, lakes, and oceans. In the second part, the emphasis moves to landforms and sediment, the interpretation of the earth's glacial legacy, and the reconstruction of glacial depositional environments and palaeoglaciology.

Rates of erosion and sediment evacuation by glaciers: A review of field data and their implications

Abstract: Diverse field data on glacial sediment yields are assembled in the context of the current interest in sedimentary basin development in glaciated regions, and in controversial linkages between global climate and topography. Attention herein is directed at sediment yields, including both overall bedrock erosion and evacuation of sediments stored in glaciated basins over several years or decades. These yields, expressed as effective rates of glacial erosion, vary by orders of magnitude from 0.01 mm yr −1 for polar glaciers and thin temperate plateau glaciers on crystalline bedrock, to 0.1 mm yr −1 for temperate valley glaciers also on resistant crystalline bedrock in Norway, to 1.0 mm yr −1 for small temperate glaciers on diverse bedrock in the Swiss Alps, and to 10–100 mm yr −1 for large and fast-moving temperate valley glaciers in the tectonically active ranges of southeast Alaska. In Alaska, current sediment yields generally increase with the extent of glacial ice cover, and are particularly high in the large heavily-glaciated basins of southern Alaska, where they exceed those of basins from other regions by about one order of magnitude. These results, supported by comparisons of sediment yields between glaciated and nonglaciated basins in Alaska, Norway and Iceland, suggest that climatic conditions favorable for the expansion of temperate valley glaciers tend to increase both mechanical and chemical denudation rates. The results are discussed in the broader context of linking erosion and climate during the ice ages of the Quaternary, and interpreting records of sedimentation from glaciated regions.

Widespread, rapid grounding line retreat of Pine Island, Thwaites, Smith, and Kohler glaciers, West Antarctica, from 1992 to 2011

Abstract: We measure the grounding line retreat of glaciers draining the Amundsen Sea sector of West Antarctica using Earth Remote Sensing (ERS-1/2) satellite radar interferometry from 1992 to 2011 Pine Island Glacier retreated 31 km at its center, with most retreat in 2005-2009 when the glacier ungrounded from its ice plain Thwaites Glacier retreated 14 km along its fast flow core and 1 to 9 km along the sides Haynes Glacier retreated 10 km along its flanks Smith/Kohler glaciers retreated the most, 35 km along its ice plain, and its ice shelf pinning points are vanishing These rapid retreats proceed along regions of retrograde bed elevation mapped at a high spatial resolution using a mass conservation technique that removes residual ambiguities from prior mappings Upstream of the 2011 grounding line positions, we find no major bed obstacle that would prevent the glaciers from further retreat and draw down the entire basin © 2014 American Geophysical Union All Rights Reserved

The Karakoram Anomaly? Glacier Expansion and the `Elevation Effect,' Karakoram Himalaya

Abstract: In the late 1990s widespread evidence of glacier expansion was found in the central Karakoram, in contrast to a worldwide decline of mountain glaciers. The expansions were almost exclusively in glacier basins from the highest parts of the range and developed quickly after decades of decline. Exceptional numbers of glacier surges were also reported. Unfortunately, there has been no on-going measurement of climatic or glaciological variables at these elevations. The present article examines possible explanations for this seemingly anomalous behavior, using evidence from short-term monitoring programs, low-altitude weather stations, and the distinctive environmental characteristics of the region. The latter involve interactions between regional air mass climatology, its seasonality, topoclimate or ‘verticality’ effects on glaciers with extreme altitudinal range, climatic sensitivities of heavy versus thin supraglacial debris, and complex temperature distributions in ice masses with ice falls through...

Fast tidewater glaciers

Abstract: Some iceberg-calving outlet glaciers flow continuously at speeds normally associated with surging glaciers arid exhibit dramatic instability scenarios related to those suggested for marine ice sheets. No temperate tidewater glaciers are known to have floating termini, but many polar and subpolar tidewater glaciers do. The fast flow of temperate calving glaciers is almost entirely due to basal sliding and appears to be a function of the effective pressure on the bed, which may approach zero, and the longitudinal back stress on the terminus. The terminus boundary condition (the calving relation) is imperfectly known yet is vital to the dynamics of these glaciers. Calving relations for grounded tidewater glaciers have been suggested on empirical grounds but have not been rigorously tested; the calving relations for floating termini are virtually unknown. This, together with the imperfect understanding of basal sliding, inhibits confidence in our understanding of the stability of these glaciers. Columbia Glacier (Alaska) is an instructive example because observations have been made on the major changes in its geometry, calving rate, and dynamics that have occurred in less than 10 years. The calving flux has increased more rapidly than the glacier flux, causing thinning and retreat; as a result, the ice velocity has increased markedly. The short-term velocity changes relate to changes in back pressure (ice recession, tidal changes) and the flux of water injected to the bed. These results have relevance to the mechanisms of basal sliding, glacier surges, and the stability of marine ice streams.