Physical geogarohy- Glacial Erosinal Landforms Flashcards
Roche mountonne definition
A mass of resistant rock which has a SMOOTH ROUNDED VALLEY SLOPE (STOSS) facing direction of ice flow and a LEE SLOPE formed from PLUCKING
Roche mountonne Process STOSS
As the glacier encounters the obstacle pressures INCREASES and allows melting to occur and BASAL SLIDING to take place. This causes the rocks trapped in the ice to ABRADE the BEDROCK.
This Abrasion on the UP VALLEY SIDE of the glacier can leave STRIATIONS as pieces of rock debris were DRAGGED across the SURFACE under Great Pressure
Roche mountonne Process LEE
On the Lee Slide pressure falls and the water refreezes as the ice MOVES DOWNHILL it pulls away rock- PROCESS OF PLUCKING
leaving a steeper sided more JAGGED LEE SLOPE
Corrie formation
EARLY STAGE OF GLACIATION- NIVATION of a small hollow on a small hillside in which SNOW ACCUMULATES year on year and compacts to GLACIAL ICE
DURING GLACIATION- the ice acquires a ROTATIONAL MOVEMENT Under it’s own weight. This ENLARGES the Hollow. Erosional processes such as PLUCKING Steepen the Back wall. The DEBRIS from the PLUCKING and WEATHERING FALLS into a CREVASSE or BERGSCHRUND which abuts the Back wall. The rock debris helps to ABRADE the hollow causing it to DEEPEN. - once the hollow has deepened the thinner ice at the front is unable to erode so rapidly, so a HIGHER LIP is left. This lip may also contain MORAINE deposited by the Ice as it moves out the Corrie
Post-Glacial- in the post glacial landscape, the Corrie may become filled with water forming a TARN or a Lake.
Glacial troughs definition
Long U-Shaped valleys - they have flat valley floors and steep straight sides
Glacial troughs formation
Formed by being carved by glaciers that have since retreated or disappeared
Ellipsoidal Basin definitions
Major erosional landforms created by ice sheets
Ellipsoidal Basin formation
Large ICE SHEETS COMPRESS the CRUSTAL SURFACE of the Earth. When the ice melts it leaves INDENTATIONS (compression hollows or dents). This leaves lakes due to meltwater.
This occurred in large portions of NORTHERN HEMISPHERE and impacted MIDWEST AND NORTHEAST United States as well as much of CANADA.
