erosional processes and landforms Flashcards
how does plucking occur?
what features does it create?
• occurs when a glacier moves over bedrock and due to pressure on the rock, it creates meltwater, which can seep into cracks in the rock.
• changes in pressure or temperature can cause the meltwater to freeze, and as the glacier moves, it “plucks” and pulls of pieces of the bedrock
• it can create roche moutonnée
what’s abrasion?
what features can it create?
• a process of erosion that occurs when a glacier moves over the landscape and scrapes against the bedrock.
• it can create smooth, polished surfaces on rocks and striations
what’s striation?
• the scratches created on rock surfaces by the movement of glaciers, during abrasion
what’s rock flour?
how is it created?
- it is a fine powder made up of tiny particles of rock that have been grounded by erosion.
-It is created when glaciers grind against the bedrock as they move, causing the rocks to break down into very small fragments.
what’s crushing?
- the breaking down of rocks into smaller fragments due to mechanical forces.
what’s basal melting?
what can it create / do?
• the process of ice melting at the base of a glacier, due to the pressure and weight of the glacier.
• it can create basal meltwater which acts like a lubricant, so the glacier to move more easily
what’s subaerial freeze thaw?
• when water seeps into cracks in rocks and then freezes and expands ( a repeated cycle)
what’s mass movement ?
give some examples.
- when soil, rock, and other materials move down a slope due to the influence of gravity.
- eg landslides and rockfalls
what is an arête?
how do they form?
- a sharp edge that forms between two glacial valleys.
- It is created when two glaciers erode the sides of a mountain and carve out steep valleys on either side.
what is a pyramidal peak?
how does it form?
- a mountain peak that has been shaped into a sharp, pyramid-like form (due to erosion)
- This occurs when several glaciers erode a mountain from different sides, creating steep ridges and a pointed summit.
what is a glacial trough?
how does it form?
- A glacial trough is a U-shaped valley that has been carved by the movement of a glacier.
- starts as a v shaped valley, which gets eroded by a glacier making the trough deeper and wider.
what is a ribbon lake?
how does it form?
- a long, narrow lake that forms in a u shaped valley
- they are created when a glacier erodes the valley floor unevenly, leaving behind deeper sections that fill with glacial meltwater
- The shape of the lake often resembles a ribbon, hence the name.
what is a corrie/cirque?
how does it form?
- a bowl-shaped depression found in mountainous regions ,
- It is created when a glacier erodes the landscape, carving out a hollow in the rock as it moves.
what are truncated spurs?
how do they form?
- landforms that are often found in glaciated valleys.
- They are formed when a glacier moves through a valley and cuts off the ends of ridges or rock that extend into the valley. The glacier erodes the sides and the front of the spur, leading to its truncation.
(think truncate as in to chop off in maths)
what is a hanging valley?
how does it form?
- a small valley that is above the main valley floor, When a glacier flows through a larger valley, it can erode the sides more deeply than it does in smaller tributary valleys.
-Hanging valleys often have waterfalls that fall down into the main valley below.
