Glacial Deposits

Glacial Deposits

 

geological deposits whose formation is genetically related to modern or ancient mountain glaciers or continental ice caps. Glacial deposits are divided into glacial deposits proper (or moraine) and aqueoglacial deposits.

Glacial deposits proper arise when fragmentai material carried within the glacier is directly deposited beneath the glacier. These deposits are composed of unsorted loose fragmentai rock, more often boulder clay, loams, and sandy loams and, more rarely, boulder sands and coarse gravel containing boulders, rock debris, and pebbles.

Aqueoglacial deposits are formed inside and along the periphery of glaciers from sorted morainic material that has been redeposited by meltwaters. Among these deposits a distinction is made between glaciofluvial deposits, which are the deposits of streams of meltwater (obliquely bedded sands, gravel, and shingle), and glaciolacustrine deposits of englacial and periglacial lakes (predominantly varved clays).

All types of glacial deposits form complicated combinations (glacial complexes or glacial formations). They are particularly characteristic for the youngest Anthropogene system, during whose formation extensive continental glaciers covered enormous areas in the present-day temperate zones. Among the deposits of the Upper Paleozoic, the Ordovician, and the Pre-cambrian, ancient glacial deposits are also known; they are usually greatly consolidated, cemented together, and sometimes also metamorphosed (tillites).

REFERENCE

Shantser, E. V. Ocherki ucheniia o geneticheskikh tipakh kontinental’-nykh osadochnykh obrazovanii. Moscow, 1966.

E. V. SHANTSER

References in periodicals archive ?
The Llandovery with its proven glacial deposits (Grahn & Caputo 1992; Caputo 1998; Diaz-Martinez & Grahn 2007), and therefore proven glacially induced sea-level fluctuations (Johnson 2006, 2010; Munnecke et al.
Scientists have suggested that over 6,000 years ago, a sharp sea-level rise, attributed to a changing climate and a rapid melting of ice, added weight to the submarine glacial deposits at the edge of the Norwegian continental shelf, destabilising them and causing a 300km long landslide.
Flying at 90 metres, aircraft use technology to see through Ireland's deep glacial deposits and peat cover.
Evans of the California Institute of Technology in Pasadena and his colleagues determined the extent of the ancient ice ages by studying glacial deposits in South Africa.
A series of glacial deposits underlie the site, consisting of Lowestoft Till and associated outwash gravels formed during the Anglian glaciation (assigned to Oxygen Isotope Stage 12, c.
These trains are characterized by varying amounts of fresh (near source) grains of pyrope and eclogitic garnets, chrome diopside, picroilmenite and olivine contained within glacial deposits.
As Late Glacial deposits are widespread in the inter-drumlin hollows of the Saadjarv Drumlin Field (Pirrus & Rouk 1979), but deglaciation timing is poorly constrained due to the absence of radiocarbon dates, Lake Prossa, where the thickness of Late Glacial deposits varies between 2 and 3 m (Saarse & Karson 1982), was selected for future study.
The rocks Macdonald and his colleagues analyzed in Canada's Yukon Territory showed glacial deposits and other signs of glaciation, such as striated clasts, ice-rafted debris, and deformation of soft sediments.
But a newer theory is that they were brought from glacial deposits much nearer the site, which had been carried down from the northern side of the Preselis to southern England by the Irish Sea Glacier.
Tight (1894b) coined the term Lake Licking for a large lake formed by glacial deposits blocking the paleovalley at Hanover to the east and the damming of the southwest-flowing paleodrainage by some undetermined glacial or interglacial agent to the southwest.
Following widespread dismissal of Agassiz's controversial claim to have discovered glacial deposits in the Amazon in 1866, the idea fell out of favour.