| what is weathering? | where the upper layers of the earths soils and rocks are exposed to physical, chemical and biological conditions which cause change to the structure of that material |
| what is mechanical weathering? (mechanical) | disintegration of rock into smaller pieces without the chemical makeup of that rock changing. |
| what does mechanical weathering include? | frost shattering and salt crystallisation |
| what is chemical weathering? | decomposition of rock where chemical reactions occur and causes changes to the internal structure of that material |
| main types of chemical weathering? | oxidation, hydrolysis, hydration and dissolution |
| what is biological weathering? | Biological weathering occurs when plants break up rocks with roots or root exudates. The process is slow, but may strongly influence landscape formation. |
| what is mass movement? | process which soil and rock move downslope under gravity and a number of underlying factors |
| what are the underlying factors? | creep, landslide (slumping) and rock fall |
| what is erosion? | removal of weathered sediment or rocks by the forces of wind, water and ice. |
| courses of a river? | upper course, middle course and lower course |
| what is transportation? | the process by which the river carries materials on its journey |
| what is deposition? | when material is deposited due to the loss of energy within the river flow |
| a river erodes in a combo of four things, what are they? | attrition, abrasion (corrasion), corrosion and hydraulic action |
| what is vertical erosion? | when the gradient is steep and the river cuts down into the valley. (v - shaped valleys!) |
| what is lateral erosion? | Sideways erosion by a river on the outside of a meander channel |
| types of transportation? | traction, saltation, suspension and solution |
| what is the bedload? | the materials transported by a river |
| what is deposition? | when a river is 'laying down' the material is it carrying, this is because of the loss of energy in the river. |
| when deposition can occur? | following a dry spell, when the current slows, when a river floods and water flows onto the floodplain, where a tributary joins a river. |
| factors affecting these processes? | climate, slope, geology, altitude and aspect |
| what is s slope? | the percent change in that elevation over a certain distance. |
| why can a slope affect a river? | on steep slopes, velocity is increased and more energy is available to erode and transport bedrock material back downstream |
| how does geology affect a river? | the internal strength of a rock will determine how resilient it is. harder rock = withstand mass movement, erosion and other processes better than softer. |
| what is altitude? | the height above sea level |
| how can altitude affect a river? | determines the energy of the river |
| what is aspect? | direction which something faces, Like north, south, west, east. |
| how can a north facing slope affect a river? | they're colder and more prone to freeze thaw which creates more loose material to be eroded and transported by the river. |
| how can a southern facing slope affect a river? | hotter, can be exposed to greater diurnal temps and lowest night time temps which can lead to higher rates of weathering |
| what is the source of a river? | starting point of a river |
| what is the long profile of a river? | a way of displaying the channel slope of a river along its entire course |
| what is the mouth of a river? | The place where a river enters a lake, larger river, or the ocean |
| which is the fastest point of a river? | upper course |
| what is it called when a river reaches maturity? | middle course |
| what are tributaries? | a freshwater stream that feeds into a larger stream or river. |
| what is a confluence? | the junction of two rivers, especially rivers of approximately equal width. |
| what is the slowest part of a river? | lower course |
| why are v-shaped valleys so steep? | soil and loose rock being washed downhill following periods of heavy rainfall |
| what are interlocking spurs? | when a river is forced to wind its way around protruding hillsides along the path of least resistance. |
| how are waterfalls created? | when there's a sudden interruption in the course of a river. When rivers meet a band of softer, less resistant rock after flowing over a relatively hard, resistant rock. the softer rock is warn away quicker, and the harder rock is undercut, then over time, it will collapse |
| how are plunge pools created? | when some of the rock from a collapse in a waterfall is swirled around by the river, during times of high discharge. |
| what is a meander? | when water flows in a curvy, bendy path, like a snake |
| how is meanders formed? | when water in the stream channel erodes the sediments of an outer bend of a streambank and deposits this and other sediment on subsequent inner bends downstream. |
| whats an ox bow lake | the remains of the bend in the river |
| how are orc bow lakes formed? | Continual erosion and deposition narrows the neck of the meander. Often during a flood the river will cut through the neck. The river continues on its straighter path and the meander is abandoned. New deposition seals off the ends and the cut-off becomes an oxbow lake that will eventually dry up. |
| what is silt? | a solid, dust-like sediment that water, ice, and wind transport and deposit. |
| how are levees formed? | The natural movement of a body of water pushes sediment to the side, creating a natural levee. |
