Unit 3 Flashcards
What is weathering?
the breakdown of rock where it is located.
this includes:
physical processes - freeze-thaw
chemical processes - carbonation
What is erosion?
the removal of rock by ice, water, wind or gravity.
What is freeze thaw weathering?
physical removal of rock after freezing and thawing until rocks crack and break.
1: temperatures fluctuate
2: when water freezes, it expands by 9% in volume
3: when it freezes, it exerts pressure on the crack
4: repeated freezing and thawing fractures the rock
What is dilatation?
1: Glaciers pressurising rock beneath
2: Glacier erodes, pressure reduced and fractures form
3: fractures expand as pressure reduces causing removal of rock
What is abrasion?
As glaciers move, the rock embedded in its base scrapes against the bedrock and wears it away
What is Plucking?
Plucking occurs when melt-water seeps into cracks in the rock of the valley floor and sides. The water then refreezes causing freeze thaw weathering. As the glacier moves, it plucks pieces of bedrock.
What is Sub-glacial Meltwater Erosion?
High velocity water beneath a glacier can erode material at glaciers bed, forming large sub-glacier meltwater channels
What is a Macro and Meso scale erosional landform?
MACRO = 1Km <
MESO = 1Km >
What is a corrie?
A large amphitheatre shaped hollow found at the head (source) of a valley glacier
What is an arête?
A sharp ‘knife-edge’ ridge which has been produced by two corres eroding back towards eachother
What is a pyramidal peak?
Where 3 or more corries around a mountain have been formed as they continue to develop back to back the remaining central area of the mountain becomes sharper and steepened
What is a glacial trough
Glacial VALLEYS/TROUGHS develop where glaciers flow into pre-existing river valleys
What is a truncated spur?
Interlocking spurs are produced as the river erodes downwards into its bed and meanders from side to side eroding laterally
What is a hanging valley?
Smaller glaciers may have its flow impaired by the larger glacier it is joining, coupled with its smaller size means that it possesses less erosive potential and therefore does not carry as much vertical erosion down into the bedrock.
What is a ribbon lake?
Long, narrow finger shaped lake, usually found in a glacial trough
