Terms
a long period of reduction in the temperature of the Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers.
ice age
a vast, flat, treeless Arctic region of Europe, Asia, and North America in which the subsoil is permanently frozen.
tundra
animals that lived more than 5,000 years ago before people could read or write.
Prehistoric animals
downhill by the force of gravity and the internal deformation of ice.
flow
occurs when rocks and stones become frozen to the base or sides of the glacier and are plucked from the ground or rock face as the glacier moves.
plucking
or glacial till is unsorted glacial sediment. Till is derived from the erosion and entrainment of material by the moving ice of a glacier.
till
a permanent layer of ice covering an extensive tract of land, especially a polar region.
ice sheet
occurs when rocks are porous (contain holes) or permeable (allow water to pass through). ... When temperatures drop, the water freezes and expands causing the crack to widen. The ice melts and water makes its way deeper into the cracks.
Freeze-thaw weathering
gradually destroy or be gradually destroyed. (of wind, water, or other natural agents) gradually wear away (soil, rock, or land).
erosion
trough valleys or glacial troughs, are formed by the process of glaciations.
U-shaped valley
is glacially deposited rock differing from the size and type of rock native to the area in which it rests.
erratic
a slowly moving mass or river of ice formed by the accumulation and compaction of snow on mountains or near the poles.
glacier
a small meandering river within a larger meandering valley which appears too big to have been formed by river erosion
Misfit river
take or carry from one place to another
transport
formed in the upper valley, the stream will most effectively erode its bed through corrosion to produce a steep-sided V-shaped valley.
V-shaped valley
are elongated, teardrop-shaped hills of rock, sand, and gravel that formed under moving glacier ice.
Drumlins
The glaciers on the mountain slope that end in the middle before approaching the main river.
Mountain glacier
is a tributary valley that is higher than the main valley. They are most commonly associated with U-shaped valleys, where a tributary glacier flows into a glacier of larger volume.
Hanging valley
is the laying down of sediment carried by wind, water, or ice. Sediment can be transported as pebbles, sand & mud, or as salts dissolved in water.
deposition
also called end moraine, is a type of moraine that forms at the snout of a glacier, marking its maximum advance.
Terminal moraine
an interval of time within an ice age that is marked by colder temperatures and glacier advances. Interglacial, on the other hand, are periods of warmer climate between glacial periods. The Last Glacial Period ended about 15,000 years ago.
Glaciations
a glacier that is confined by surrounding mountain terrain
Alpine glacier
the uneven blanket of till deposited in the low-relief areas between more prominent moraine ridges
Ground moraine
when pebbles grind along a rock platform, much like sandpaper. Over time the rock becomes smooth.
abraision
forms along the sides of a glacier. As the glacier scrapes along, it tears off rock and soil from both sides of its path. This material is deposited as lateral moraine at the top of the glacier's edges
Lateral moraine