Earths Resources - Geosphere Flashcards
weathering
rock cycle processes
the exposure and breaking down of rocks in situ at the Earth’s surface over geological time due to interaction with the atmosphere.
transportation
rock cycle processes
the movement of rock fragments by water, wind, ice or gravity from the place where they were originally weathered.
erosion
rock cycle processes
the breaking down of rock fragments into smaller pieces and sediments due to collision with other rock fragments during transportation.
deposition
rock cycle processes
the setting out of rock fragments and sediments after transportation by water, wind, ice or gravity.
rock
a solid mass made of one or more materials
mineral
an element or chemical compound formed as a result of rock cycle processes
ore
a naturally occurring solid material from which a metal or valuable mineral can be extracted profitably
porosity
a measure of a rock’s ability to hold fluid
permeability
a measure of the amount of water allowed to pass through a rock
chemical weathering
the dissolving or disintegration of racks by weak acids e.g. acid rain
(usually small holes/dimples in the rock)
biological weathering
disintegration of rocks by the action of living organisms e.g. plant roots or animal burrowing
physical weathering
weakening of rocks by abrasion, frost shattering or temperature changes
hydraulic action
when the sheer force of the water gets into the small cracks and breaks down the rock
rivers/sea
abrasion/corrosion
when the load hits against the river bed or banks or sea cliff, ice scrapes across the landscape, wearing away the rock
attrition
when the load repeatedly knocks into each other and causes the rock to break
rivers/sea
corrosion
water dissolves minerals from rocks and washes them away OR weak acids in the water dissolve the rock
rivers/sea
igneous rocks
volcanic rocks which form from molten rock under the earths crust
basalt, granite, pumice
sedimentary rocks
fromed from sediments which have settled below a body of water, and have been compressed over millions of years
sandstone, limestone, chalk, clay, coal and oil (fossil fuels)
metamorphic rocks
rocks formed by being subjeted to tremendous heat and pressure
marble (limestone), slate (clay), schist (sandstone or shale)
intrusive
igneous rock
magma cools slowly underground
extrusive
igneous rock
lava cools quickly on the surface
limestone
formation
- remains of coral and sea life - which contain calcium carbonate (CaCO3) - are laid down at the bottom of tropical seas (during Carboniferous period, 300 million years ago)
- precipitation reaction occurs forming precipitate
- precipitate and sediments are compressed over millions of years to form limestone
limestone
uses
- Building material
- Production of cement by heating powdered limestone with clay
- Toothpaste
- Food additive
- Neutralise acidic soil
- Removes impurities from blast furnace when making iron
limestone
environmental impacts (extraction)
- noise pollution - extraction can be loud scaring farm animals and be frustrating for locals
- air pollution - dust from explosions can damage nearby crops and cause (respiritory) health risks for the human population
- water pollution - dust and debris is washed into rivers and streams
- visual pollution - quarries ruin the scenery
- heavy lorries - cause traffic congestion and potholes when transporting the limestone
crude oil
formation
formed from the remains of small animals and plants that died and fell to the seafloor millions of years ago. These remains were then compressed and heated within the Earth’s crust to form oil
crude oil
processing
- fractional distillation is used to separate the different fractions of the oil
- each fraction has a different boiling point which allows them to be separated from each other in a distillation collumn
crude oil
uses
- fuels (deisel, petrol, kerosine)
- plastics
- medicines
- cosmetics
crude oil
environmental impacts (extraction, processing, & uses)
- ecosystem loss & terrestrial deforestation - oil drilling disturbs terrestrial and aquatic ecosystems, seismic techniques can impact marine life, drilling on land can require the destruction of vegetation
- water pollution - oil leaks/spills contaminate water effecting drinking supply, irrigation, marine life etc.
- soil pollution - oil spills can contaminate soil and kill vegetation and crops
- air pollution - burning fuels releases particulate matter which contributes to greenhouse effect
iron
formation
- algae-like bacteria photosnthesised releasing oxygen
- oxygen reacts with dissolved iron in the water to form hydroxides and iron oxides
- these insoluble materials settle on the sea bed
- iron rich sediments are moved and changed by crustal plates to form magnetite and haematite deposites
iron
processing
- iron is extracted from its ore in a blast furnace at high temperatures (1800ºC) in a series of reduction reactions
- carbon (coke) is more reactive than the iron, removing the oxygen from the iron oxide
- limestone is used to ‘soak up’ impurities producing a waste product called slag
iron
environmental impacts (extraction & processing)
- air pollution - harmful gases (N2O, CO2, CO, SO2) are released in extraction and processing
- water pollution - during extraction dirt and debris contaminates nearby water
- deforestation, habitat destruction, soil erosion - trees cleared for extraction
