Start Optically stimulated luminescence dating of fluvial deposits

Optically stimulated luminescence dating of fluvial deposits

Note the large, faceted boulders at the boundary between the two tills. This means that under some glaciers in cold environments, such as the Dry Valleys in Antarctica, pressure melting point is not reached and the glacier remains frozen to its bed. Geological Society of London Special Publication: London.

Within ice sheets, Kleman and Glasser 2007[14] identify four major ice-dynamical components found within ice sheets, including the Antarctic Ice Sheet.

They are: frozen-bed patches, ice streams, ice stream tributaries, and lateral shear zones.

In temperate regions, such as the Alps[e.g., 4], many glaciers reach pressure melting point, where ice at the base of a glacier melts[1, 5].

Debris may be an obstacle to the ice, which causes melting and refreezing in the lee of the object.

Successful application of OSL techniques can be judged in a number of ways: comparison with the 'independent' chronologies is prevalent in the literature, but recently the movement towards measurement of large numbers of small aliquots and single grains allows a more robust assessment of luminescence properties and behaviour for individual samples and ultimately more precise luminescence ages to be determined.

For glaciofluvial sediments in particular, it is important to investigate the depositional sub-environment of each sample in relation to the chance of sufficient bleaching during transport and deposition. ABSTRACT: Climatically, the eastern Himalaya are mainly controlled by the Indian Summer Monsoon (ISM) and important region for understanding the relationship between ISM and glacial change.

In this section, we describe, firstly, different kinds of thermal regimes, before looking at their processes and products in Antarctica.

The thermal regime of a glacier is a function of ice temperature (which again is a function of air and ground temperatures, with some glaciers being heated from below by geothermal heating) and the pressure of the ice.

For glacigenic sediments, Optically Stimulated Luminescence (OSL) dating offers an opportunity to date the time of deposition of quartz and feldspar minerals that are ubiquitous within the sediment matrix, rather than relying upon the chance occurrence of organic material for radiocarbon dating.

The OSL dating signal or charge accumulates in crystal defects of individual quartz and feldspar minerals through exposure to environmental radiation within their depositional setting.

Between these two end members, polythermal glaciers have beds that are frozen and unfrozen. Rippin, D., Willis, I., Arnold, N., Hodson, A., Moore, J., Kohler, J., and Björnsson, H., 2003.