Lithosphere Flashcards
What parts of the Earth consist of the lithosphere?
Solid crust and upper mantle
What does the lithosphere include?
Rocks, mineral resources and soils that provide environmental resources
What are the major uses of iron?
Ships, road vehicles, rail track bridges, cookers, fridges and washing machines
What are the major uses of aluminium?
Packaging foil and vehicles window frames
What are the major uses of copper?
Electric cables and water pipes
What are the major uses of zinc?
Galvanising, batteries and alloys (brass)
What are the major uses of titanium?
White pigments in paint, paper and plastics and aircraft/ spacecraft
What are the major uses of tin?
Solder, rust prevention and glass manufacture
What are the major uses of cadmium?
Rechargeable batteries
What are the major uses of platinum?
Vehicle catalytic converters and catalyst in the chemical industry
What are the major uses of aggregates (sand and gravel)?
Concrete, building mortar, glass
What are the major uses of limestone?
Cement, crushed for road surfacing and rail track ballast, building blocks
What are the major uses of salt?
Source of chlorine for manufacture of paper, plastic and water sterilisation, the de-icing of roads and food additives
What are the major uses of sulphur?
Sulphuric acid manufacture to make phosphate fertilisers and pest control
What is the total mass of minerals extracted per year?
55 billion tonnes
What are the three types of rock?
Igneous, sedimentary and metamorphic
How are igneous rocks formed?
From the cooling and hardening of molten lava or magma
What are igneous intrusions?
Rocks formed from magma that cools and solidifies within the Earth’s crust
What conditions do igneous intrusions cause?
Pressurised, superheated water at high temperatures that dissolves many minerals from the surrounding rocks
What happens to mineral rich solutions from igneous intrusions?
They travel along fissures away from the igneous batholith, cooling as they do so, minerals crystallise in order of solubility
What are hydrothermal depositions?
Mineral deposits formed from fractional crystallisation of minerals in water
What ores are deposited by hydrothermal processes?
Tin, copper, lead, silver, gold and arsenic
How are metamorphic rocks formed?
High temperatures and pressures, without melting, caused by tectonic movement of crustal plates
What is sedimentary rock?
Layers of mineral build-up producing deposited sediment
How does limestone change to marble?
High temperatures and extreme pressures
How does mudstone change to slate?
Extreme pressure
What are Proterozoic marine sediments?
Iron ore deposits, such as hematite and magnetites, formed when dissolved iron compounds became oxidised by the oxygen from photosynthesis
What are alluvial deposits?
Materials carried and separated by flowing water (surface runoff)
What’s the order of deposits in alluvial deposition?
Decreasing in density then decreasing in size
What materials are found in alluvial deposits?
Gold, diamonds, tin ore, gravel, sand and clay
What are evaporites?
Evaporated water leaves crystallised minerals such as halite
What are some examples of when evaporites form?
A bay of ancient sea becomes isolated or inland seas in desert areas as the water from inflowing rivers evaporates
What are biological sediments?
Living organisms form mineral deposits e.g. shells of marine organisms make limestone and chalk, terrestrial vegetation makes coal and marine organisms make crude oil and natural gas
What’s Lasky’s principle?
As the purity of a mineral decreases the amount of mineral present increases exponentially
What’s the major problem with future mineral supplies?
Not the quantity that exists, but the ability to exploit low grade ores
What is stock?
All material that exists in the lithosphere
What is a resource?
Includes all material that is theoretically available for exploitation, all available now and that could be realistically in the future
What is a reserve?
The amount of resource that is currently economically available for exploitation
What are inferred reserves?
The presence of the mineral can be predicted from knowledge of the geological structures present but not enough is known to estimate the amount that can be economically viable
What are probable reserves?
Sufficient information about the deposit is known, so the amount of the mineral that can be economically extracted can be estimated with sufficient accuracy that further exploration is justified
What are proven reserves?
Sufficient exploration has been carried out, including trial drilling to accurately estimate the amount of the mineral that can be economically extracted
What factors will limit the viability of exploration?
The absence of the technology to exploit the deposits, the financial cost of exploration my be too great and the environmental impact of exploitation may be unacceptable
What is remote sensing?
Involves any technique that give information without taking direct samples
What are the surveying techniques?
IR spectroscopy, gravimetry, magnetometry, seismic surveys, resistivity, trial drilling and chemical analysis
How does IR spectroscopy work?
Different minerals emit different wavelengths of infrared radiation
How does gravimetry work?
Detect variations in gravity caused by variations in density and mass
How does magnetometry work?
Detect rocks that are more magnetic such as magnetite
How do seismic surveys work?
Involve sound waves produced by controlled explosions, or a seismic vibrator on the surface, the echoes give information about the depth, density and shape of rock strata
How does resistivity work?
Measurement of the difficulty with which electricity passes through a material
How does trial drilling work?
Most expensive technique per sampling site but is the only methods that actually produces samples of the rocks underground
How does chemical analysis work?
Laboratory tests confirm the chemical composition and purity of the minerals in the rock samples
What factors must be considered before mining can begin?
Ore purity, chemical form, overburden and hydrology, depth, cut off ore grade, transport costs and market economics
What is overburden?
The rock that lies above the mineral deposit
What are the risks with overburden?
Hard overburden may have to be blasted, which increases cost and loose overburden may increase the risk of landslides
How does hydrology affect mining?
Higher precipitation or impermeable rocks below may increase drainage costs
How does depth effect mining?
As depth doubles, cost increases exponentially as the sides of the mine cannot be vertical due to risk of collapse
What is the cut-off ore grade?
The lowest ore purity that can be mined economically, using existing technology
How does market value effect COOG?
As market value increases the COOG decreases
How does energy costs effect COOG?
As energy costs increase the COOG increases
How much of the Earth’s land surface has been mined?
About 1%
What are the environmental impacts of mineral exploitation?
Land take, habitat loss, loss of amenity, dust, noise, turbid drainage water, spoil disposal and mine site restoration
Which type of mining causes more habitat loss?
Open cast mine
How does turbid drainage water of mines effect the environment?
Suspended solid particles reduce light penetration into rivers and lakes, sediments can also cover and kill plants and animals
How is turbid drainage water of mines effect reduced?
Using sedimentation lagoons in which the water stands still long enough for the solids to sink
What problems can be caused by spoil disposal?
Aesthetics, stability and leachate
What stability risks does spoil disposal provide?
Lack of compaction reduces stability and leads to erosion, water-logging from rainfall can cause landslides
What are leachate risks with spoil disposal?
Rainwater can percolate and dissolve toxic metals and sulphides to produce acidic leachate solutions becoming more mobile
What methods can be used to prevent acidic leachate?
Placing crushed limestone filter beds as many toxic metals are only soluble in acidic conditions, it clears the water before feeding it into a river
What are some improvements in exploratory techniques?
Better remote sensing image resolution and portable field equipment
How has field equipment become more portable?
Electronics have become lighter, more powerful batteries have been developed and energy consumption has been reduced
What are some mechanisation improvements?
Deep mining and open-cast mining
What are newly developed methods of low grade ore extraction?
Bioleaching, phytomining, iron displacement, leachate collection and polymer adsorption
What are the normal methods for extracting metals form their ores?
Smelting, which involves chemical reductions at high temperatures
What is bioleaching?
The use of living organisms to extract metals from their ores
What is an example of bioleaching?
Acidophilic bacteria can be used to extract metals such as copper, zinc, lead and gold from low-grade sources, the bacteria oxidises sulphide ores, which produces sulphuric acid that dissolves the metals
What is phytomining?
Harvesting and incinerating vegetation, to dissolve concentrated metals in the ash in acid, as plants uptake metals
How does iron displacement work?
Displaces copper ions within a solution as iron is more reactive
How does collection of leachate work?
Leachate from spoil heaps is recirculated to increase the concentration of metals before removing by electrolysis
Where have rare earth metals been found in high concentrations?
Deep sea sediments, but the technology to exploit these deposits has not yet been developed
How does polymer adsorption work?
Metal ions dissolved in sea water adsorb onto some polymers to be collected later
What polymers can be used for polymer adsorption?
Synthetic polymers can be used, as can natural polymers such as lignin and chitin
What are polymetallic (or manganese) nodules?
5 to 10cm diameter at depths of 4000 or 5000m containing manganese, iron, nickel, copper, cobalt and titanium
What are the environmental impacts of polymetallic nodule exploitation?
Recovering nodules disturb the seabed and kill benthic organisms that live there, increases the turbidity of water with unknown consequences
What are the two types of waste?
Pre-consumer and post-consumer
What waste material can be collected roadside for recycling?
Paper, cardboard, garden waste, metals, plastic bottles and glass
What waste should be taken to local recycling centres?
Batteries, vehicle engine oil, building rubble, soil, clothing and textiles, books and electrical items
What are the problems with recycling schemes?
Transport, labour costs, separation of alloys, identification, energy costs, public cooperation and waste losses
How do labour costs effect recycling schemes?
Processing smaller quantities of materials increases labour costs, however recycling doesn’t require the same skills as extraction
How does identification of materials effect recycling schemes?
Labour intensive and slow work
How do waste losses effect recycling schemes?
Lost in litter and placed in general waste for landfill
What is Cradle to Cradle design?
The design of products so that the materials used are able to be reused at the end of their useful lives
What is an example of polymer adsorption?
It provides low-energy extraction of uranium for nuclear power fuel
What are fossil fuels?
Hydrocarbons from organisms remains
What is a batholith?
Large igneous intrusion
What is a placer deposit?
Accumulation of valuable minerals
What is subsidence?
Gradual caving in or sinking of an area of land
Why is land with heavy metal contamination regarded as unsuitable for recreational activities?
Ingestion of soil, skin problems
Why is land contaminated with heavy metals regarded as unsuitable for food production?
Uptake by plants
What are some non-metallic minerals?
Sand, limestone, clay, slate, sandstone, granite and gravel
How can the pH of soils be increased?
Addition of CaCO3 or other alkali substances
What is toxic leachate?
Dissolved metals that move through soil within a solution that causes harm to biota
What are two rocks that can be used in road surfacing and what qualities are needed?
Basalt and sandstone, must be impermeable and low solubility
