Search results
Results from the WOW.Com Content Network
Till or glacial till is unsorted glacial sediment. Till is derived from the erosion and entrainment of material by the moving ice of a glacier. It is deposited some distance down-ice to form terminal, lateral, medial and ground moraines. Till is classified into primary deposits, laid down directly by glaciers, and secondary deposits, reworked ...
Rock flour, or glacial flour, consists of fine-grained, silt-sized particles of rock, generated by mechanical grinding of bedrock by glacial erosion or by artificial grinding to a similar size. Because the material is very small, it becomes suspended in meltwater making the water appear cloudy, which is sometimes known as glacial milk .
Glacial erratic boulders in Island County are a remnant of the Pleistocene glaciation that created Puget Sound and transformed the surfaces of what are now Island County's main landmasses: Whidbey Island and Camano Island. South of Deception Pass, the two islands' surfaces and beaches are completely composed of glacial till.
Moraines are landforms composed of glacial till deposited primarily by glacial ice. [2] Glacial till, in turn, is unstratified and unsorted debris ranging in size from silt-sized glacial flour to large boulders. [3] The individual rock fragments are typically sub-angular to rounded in shape. [4] Moraines may be found on the glacier's surface or ...
Fluvioglacial deposits differ from glacial till in that they were deposited by means of water, rather than the glacial itself, and the sediments are thus also more size sorted than glacial till is. The stone walls of New England contain many glacial erratics, rocks that were dragged by a glacier many miles from their bedrock origin.
Drift is often subdivided into unstratified (unsorted) drift (glacial till) that forms moraines and stratified drift (glaciolacustrine and fluvioglacial sediments) that accumulates as stratified and sorted sediments in the form of outwash plains, eskers, kames, varves, and so forth. The term drift clay is a synonym for boulder clay. Both are ...
These are the principal deposits during the winter because of lack of melting of the glacier so the stream has a reduced discharge therefore carrying less coarse material. These sediments normally consist of fine-grained rhythmites that are laid down in layers known as varves or varvites. A varve represent an annual deposit of silt and clay.
Fine sediment and particles are also incorporated into the glacial ice. The accumulation of these rocks and sediment together form what is called glacial till when deposited. Push moraines are formed when a glacier retreats from a previously deposited terminal moraine, only to push proglacial sediment or till into an existing terminal moraine ...