1.Pertaining to ice, especially in great masses, such as sheets of land ice or glaciers. 2.Pertaining to an interval of geologic time that was marked by an equatorward advance of ice during an ice age
; the opposite of interglacial phase. These intervals are variously called glacial periods, glacial epochs, glacial "stages," etc.
(1) Period of time during an ice age when glaciers advance because of colder temperatures. (2) Involving glaciers and moving ice. Usually pertaining to processes associated with glaciers.
When a mountain glacier's terminus extends farther downvalley than before; occurs when a glacier flows downvalley faster than the rate of ablation at its terminus.
Glacial advance is the net movement of glacier terminus downvalley. Advance occurs when the rate of glacier flow downvalley is greater than its rate of ablation. Advances are characterized by a convex
-shaped terminus.
A type of semipermanent anticyclone that has been said to overlie the ice caps of Greenland and Antarctica. As presented by W. H. Hobbs, it was thought that these anticyclones played a dominant part i
n the world atmospheric circulation, but modern theory backed by limited observation has tended to diminish their importance and even to question their reality. (Or glacial high.)
Glacial drift is the loose and unsorted rock debris distributed by glaciers and glacial meltwaters. As glaciers melt, their remaining load of rocks is distributed in several ways. Rocks may be dropped
in place by the melting ice; they may be rolled to the ice margins, or they may be deposited by meltwater streams. Collectively, these deposits are called 'glacial drift'. 'Till' refers to the debris deposited directly by the glacier. Rock debris rolls off the glacier edges and builds piles of loose unconsolidated rocks called 'glacier moraine'. 'Lateral moraines' form along the side of a glacier and curl into a 'terminal moraine' at the glacier's downvalley end. Drift and moraines are valuable to geologists because they outline the boundaries of past glaciations.
All rock material in transport by glacial ice, and all deposits predominantly of glacial origin made in the sea or in bodies of glacial meltwater, including rocks rafted by icebergs. "Glacial drift oc
curs as scattered rock fragments, as till [rocks mixed with finer material], and as outwash [fine material with no rocks]. Contrast with angular drift."(from Glossary of Arctic and Subarctic Terms 1955).
This is the environment where Glaciers are located. It often includes unglaciated mountain peaks, called nunataks. Glaciers, Ice Caps, icefields and other surface Snow and Ice form an frozen water sys
tem that interacts with the atmosphere and hydrosphere. Glacial environments are characterized by a suite of distinct geomorphic processes and their associated landforms.