glaciated landscapes test Flashcards
what are the 10 landforms of glacial erosion
cirque, arete, pyramidal peak, glacial trough, truncated spur, hanging valley, ribbon lake, roche moutonnee, knoch and lochan, crag and tail
tell me about cirques
Amphitheatre-shaped depression with a steep back wall and a rock lip. A large rounded hollow high on a mountainside is eroded and deepened by plucking and abrasion due to the rotational ice movement of a cirque glacier. E.g. Cwm Idwal Snowdonia
tell me about an arete NOW
A narrow, knife-edged ridge between two cirques. Plucking and abrasion on the back wall of two cirques means they erode backwards towards each other, creating a narrow ridge, freeze thaw forms the sharply pointed summit. E.g Striding Edge Lake District
tell me about pyramidal peaks
a pointed mountain peak with three or more cirques. pretty much same as arete, plucking is important. E.g The Matterhorn Alps
tell me about glacial troughs NOW
A U-shaped valley with steep sides and a wide, flat floor. Plucking and abrasion widen a V-shaped river valley from a valley glacier E.g Nant Francon Valley Snowdonia
tell me about truncated spurs
Steep rocky valley sides where spurs of a river valley used to interlock before glaciation. Valley glaciers remove the ends of interlocking spurs by plucking and abrasion as they move down the river valley. E.g The Devil’s point in upper Glen Dee
tell me about hanging valleys
a small tributary v-shaped or small u-shaped valley high above the main glacial trough floor, often with a waterfall as the river flows over the edge. Powerful thicker glacial ice in the main glacial trough eroded vertically downwards more rapidly than thinner ice or rivers in tributary valleys are left high above the main valley floor. E.g Pistyll Rhaedr, Berwyn Mountains Wales
tell me about ribbon lakes
a long, narrow lake along the floor of a glacial trough, areas of increased plucking and abrasion by the valley glacier deepen part of the valley floor as a result of either the confluence of glaciers or weaker rocks, sometimes the lake forms behind a terminal moraine after glaciation. E.g Windermere england
tell me about Roche moutonnée
A mass of bare rock on the valley floor with a smooth stoss (up-valley side) and a steep jagged lee (down-valley side). A more resistant rock outcrop causes ice movement by creep and regelation around it, as the ice slides around the rock, it scours and smoothes the stoss, while refreezing on the lee causes plucking. E.g Lembert Dome, Yosemite National Park, California
tell me about Knock and lochan
a lowland area with alternating small rock hills (knock) and hollows, often containing small lakes (lochan). Scouring at the base of a glacier excavates areas of weaker rock, forming hollows that fill with meltwater and precipitation following ice retreat. Shetland Island scotland
tell me about crag and tail
a very large mass of hard rock forms a steep stoss with a gently sloping tail of deposited material. A large mass of hard rock is resistant to ice scouring and creates a steep stoss. Reduced glacier velocity on the lee protects softer rock and allows deposition but the sheltering effect diminishes with distance, creating a sloping tail. Castle Rock Edinburgh
what are 7 landforms of fluvio glacial deposition
Kame, Kame terrace, Esker, Sandur, Kettle hole, Proglaial lake, Meltwater channel
tell me about kames
an undulating mound of fluvio-glacial sand and gravel deposited on the valley floor near the glacier snout.
As meltwater streams emerge onto the outwash plain or proglacial lake at the glacier snout, their velocity suddenly falls and sediment is deposited. The Baden Hills, in Canada
tell me about kame terraces
a flat, linear deposit of fluvio-glacial sand gravel deposited along along the valley side. During the summer the valley sides radiate heat, melting the edge of the glacier and forming meltwater streams, which deposit sediment, When the glacier retreats, the sediment will fall to the valley floor, forming a kame terrace. The Loch Etive Scotland
tell me about dem Eskers
A long, narrow, sinuous ridge of fluvio-glacial sand and gravel. Subglacial streams can carry large amounts of rock debris du to their high hydrostatic pressure inside tunnels. the streams often meander beneath the glacier. When the glacier retreats, the debris load is deposited at a consistent rate and forms a ridge. the Badelundasen esker, Sweden
tell me about Sandurs
a flat expanse of fluvio-glacial debris in front of the glacier snout. As meltwater streams emerge from the glacier and enter lowland areas, they gradually lose their energy and deposit their debris load. The coarse gravels are deposited first, then the sands, and finally clay farthest from the glacier. E.g Usk valley England
tell me about kettle holes
a circular depression, often forming a lake in an outwash plain. As the glacier retreats, detached blocks of ice remain on the outwash plain, meltwater streams flow over the ice, covering them in deposits of fluvio-glacial debris, eventually the ice melts and the debris subsides to form a depression, which often fills with water to form a kettle-hole lake. E.g Sunfish lake Minnesota US
tell me about proglacial lakes
a lake formed in front of the glacier snout. Formed by the damming action of a terminal or recessional moraine during the retreat of a melting glacier, or because hills block the escape of meltwater, can also be formed by meltwater trapped by an ice sheet as a result of isostatic depression of the crust around the ice. E.g Lake Algonquin North America
tell me about meltwater channels
a narrow channel cut into bedrock or deposits, either underneath or along the front of an ice margin. Meltwater can erode deep channels, even gorges, as a result of the high hydrostatic pressure within the glacier and their high sediment load. high hydrostatic pressure of the glacier means the streams can flow uphill and are often larger than post-glacial stream, braiding is common due to seasonal variations in discharge. E.g southern margins of the Pentland Hills in Scotland
what is plucking
Plucking is a process of erosion that occurs during glaciation. As ice and glaciers move, they scrape along the surrounding rock and pull away pieces of rock which causes erosion.
what is the Greenland ice sheet’s environmental value in terms of supporting biodiversity
support a fragile biodiversity of endemic plants, large mammals such as polar bear, reindeer, Arctic fox and whale, and a diverse range of fish and birds. Opportunities for scientific research.
what % of total global ice mass does the Greenland ice sheet have
10%
if the whole Greenland ice sheet melted how much would sea level increase by globally
7 metres, countries such as Bangladesh and the Maldives would disapear entirely
what is the Greenland ice sheet’s cultural value
support the traditional lifestyle of the Inuit, holds value for scientific research as it contains a unique record of the Earth’s climate history, trapped gases, dust, pollen and water molecules
the Greenland ice sheet’s economic value
contains the world’s biggest unexploited hydropower capacity, resources such as oil, tourism
the Yamal Peninsula’s environmental value
provides a summer home for many migratory bird species and thus plays a role in worldwide food webs, stores twice as much twice as much carbon as is in the atmosphere
