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level: Level 1

Questions and Answers List

level questions: Level 1

QuestionAnswer
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 lakethe 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.