Results 191 to 200 of about 2,943 (230)

Subglacial till: Formation, sedimentary characteristics and classification [PDF]

open access: yesEarth-Science Reviews, 2006
We review the major subglacial till forming processes as presently understood by glacial researchers and define the parameters within which tills are produced and reconcile them with sedimentary end members.
D J A Evans
exaly   +2 more sources

Microstructural interpretations of modern and Pleistocene subglacially deformed sediments: the relative role of parent material and subglacial processes

Journal of Quaternary Science, 2001
AbstractAnalysis of till micromorphology represents a relatively new technique that has been used most frequently to infer the importance of subglacial shear in till genesis. This study aims to calibrate the technique by comparing Pleistocene tills from United Kingdom with a modern till (the UpB till) from beneath Ice Stream B, West Antarctica. Despite
Anjana Khatwa, Slawek Tulaczyk
openaire   +1 more source

Characteristics of the subglacially-formed debris-rich chemical deposits and related subglacial processes of Qiangyong Glacier, Tibet

Journal of Geographical Sciences, 2003
Subglacially-formed debris-rich chemical deposits were found both on bedrock surface and in bedrock crevice on the edge of Qiangyong Glacier, one of the continental glaciers in Tibet. Grain size distribution, internal structures and chemical components of the chemical deposits were analyzed.
Luo Risheng   +3 more
openaire   +1 more source

Assessing subglacial processes from diatom fragmentation patterns

Geology, 2004
Reconstructing the size and glacial style of past ice-sheet advances requires interpreting complex glacial sedimentary facies. We use diatoms, a major component of Antarctic continental shelf deposits, to infer the physical conditions under which these deposits were emplaced.
Reed P. Scherer   +3 more
openaire   +1 more source

Isotopic identification of subglacial processes

2010
A comprehensive stable isotope study of basal ice and debris layers in two Yukon surging glaciers suggests an isotopically variable basal freezing cycle. Trapridge and Backe Glaciers, St. Elias Range, Yukon, Canada, have parallel basal debris layers that extend for hundreds of metres along marginal ice faces and in meltwater tunnels.
openaire   +1 more source

Processes and environmental significance of the subglacial chemical deposits in Tianshan Mountains

Science in China Series D: Earth Sciences, 2005
On the bedrock surface of Glacier No.1 in the headwater of Urumqi River, Tianshan Mts., well layered and crystallized subglacial calcite precipitations were discovered. Based on observations and analysis of the surface form, sedimentary texture and structure, and chemical composition of the deposits, clues about the subglacial processes and environment
Gengnian Liu   +3 more
openaire   +1 more source

An investigation of subglacial processes at the microscale from Briksdalsbreen, Norway

Sedimentology, 2006
AbstractThe subglacial processes at Briksdalsbreen, Norway, are examined by a combination of sedimentology, thin section and scanning electron microscope (SEM) analysis of till samples from an exposed subglacial surface and from beneath the glacier.
openaire   +2 more sources

Physical, chemical and biological processes in Lake Vostok and other Antarctic subglacial lakes

Nature, 2001
Over 70 lakes have now been identified beneath the Antarctic ice sheet. Although water from none of the lakes has been sampled directly, analysis of lake ice frozen (accreted) to the underside of the ice sheet above Lake Vostok, the largest of these lakes, has allowed inferences to be made on lake water chemistry and has revealed small quantities of ...
Siegert, MJ   +6 more
openaire   +4 more sources

Subglacial till: A physical framework for its properties and processes

Journal of Geophysical Research: Solid Earth, 1987
The continuum theory of mixtures provides a framework around which present knowledge of subglacial till can be organized. The proposed framework is provisional in two senses: the constitutive description of till will require improvement, and not all potentially significant processes have been included.
openaire   +1 more source

Particle and aggregate mobility in till: Microscopic evidence of subglacial processes

Quaternary Science Reviews, 1997
Abstract Microscopic studies of tills show that the deforming bed of glaciers is made up of minute rotational elements or wheels, consisting of a nucleus alone or a nucleus with spiralling arms of fine grains. These fine grains can move from one wheel to the next, providing a process of high grain mobility within a deforming subglacial till ...
openaire   +1 more source

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