Mass Movement/Weathering Processes Flashcards
What is a dalmatian coast? (mass movement)
A dalmation coastline is formed where the geology creates valleys parallel to the coast so that when sea level rises, a series of elongated islands remain offshore.
What is an emergent and submergent coastline? (mass movement)
Emergent: occurs when isostatic rebound is faster than eustatic rise. Previously submerged coastline prevails above water.
Submergent: eustatic rise faster than isostatic rebound. Previously above sea level coastline becomes submerged under water.
What causes fjords and fjards to form?
Flooding from sea.
What is frost shattering?
Water enters cracks in rock, freezes and expands and weakens the rock as a result. It often produces scree at the bottom of a cliff.
What is hydraulic action?
This is when water (generally from powerful waves) rushes into cracks in the rock face rapidly. This traps a layer of air at the bottom of the crack, compressing it and weakening the rock.
What is the difference between isostatic and eustatic change? (mass movement)
Isostatic: rise or fall of land
Eustatic: rise or fall of water (sea)
What is mass movement?
Mass movement or mass wasting is movements of masses of bodies of soil, bed rock, rock debris, soil, or mud which usually occur along steep-sided hills and mountains because of the pull of gravity. This slipping of large amounts of rock and soil is seen in landslides, mud slides, and avalanches.
What is a mudflow?
A mudflow is a form of mass movement involving very rapid to extremely rapid surging flow of debris that has become partially or fully liquified by the addition of significant amounts of water to the source material
What is weathering and what are the three main types of weathering.
The process by which rocks are broken down into small grains and soil.
Chemical: the change in the composition of rocks, often leading to a ‘breakdown’ in its form. This type of weathering happens over a period of time.
Mechanical: the cause of the disintegration of rocks. The primary process in mechanical weathering is abrasion - the process by which clasts and other particles are reduced in size.
Biological: the weakening and subsequent disintegration of rock by plants, animals and microbes. (eg. Growing plant roots can exert stress or pressure on rock.) Although the process is physical, the pressure is exerted by a biological process.
What is oxidation?
Oxidation takes place when oxygen combines with other elements in rocks to form new types of rock. These new substances are usually much softer, and thus easier for other forces to break apart.
What is rotational slumping?
Rotational slumps occur when a slump block, composed of sediment or rock, slides along a concave-upward slip surface with rotation about an axis parallel to the slope. Rotational movement causes the original surface of the block to become less steep, and the top of the slump is rotated backward.
What are sub-aerial processes?
Sub-aerial processes are land based processes which alter the shape of a coastline. They’re a combination of both weathering and mass movement.
What are boring molluscs?
Molluscs that bore holes into rocks and cause biological weathering by thus weakening the rock.
What is scree/talus?
A mass of loose particles found at the bottom of a cliff as a result of weathering.
What is salt crystallisation?
Salt crystallization, otherwise known as haloclasty, causes disintegration of rocks when saline solutions seep into cracks and joints in the rocks and evaporate, leaving salt crystals behind. These salt crystals expand as they are heated up, exerting pressure on the confining rock.
