How are glacial deposits formed?

Debris in the glacial environment may be deposited directly by the ice (till) or, after reworking, by meltwater streams (outwash). As the ice melts away, the debris that was originally frozen into the ice commonly forms a rocky and/or muddy blanket over the glacier margin. …

How does all the sediment that is carried in or on a glacier get there?

Sediments transported and deposited by glacial ice are known as till. Supraglacial sediments are primarily derived from freeze-thaw eroded material that has fallen onto the ice from rocky slopes above. These sediments form lateral moraines (Figure 16.1) and, where two glaciers meet, medial moraines.

What are two types of glacial deposits?

Glacial deposits are of two distinct types:

Glacial till: material directly deposited from glacial ice. Till includes a mixture of undifferentiated material ranging from clay size to boulders, the usual composition of a moraine.
Fluvial and outwash sediments: sediments deposited by water.

What is the difference between a terminal moraine and a recessional moraine?

Terminal and recessional moraines mark the farthest reaches of a glacier—its terminus—at a given point in time. If, on the other hand, a glacier retreats more quickly, and its terminal position changes every few years, it may leave a series of smaller recessional moraines, rather than a large terminal moraine.

Are both deposited by meltwater streams?

Eskers and kames are deposited by meltwater streams; they are composed of stratified sand and gravel. Sand and gravel deposited by glacial meltwater streams are known as outwash till or stratified till.

Which is one of the two major flow mechanisms in a glacier?

Glaciers flow primarily because the ice within them deforms under the influence of gravity. Glacier flow is achieved by three mechanisms: internal deformation, basal sliding, and subglacial bed deformation (Figure 7). Internal deformation is achieved by the processes of ice creep, large-scale folding, and faulting.