Chapter 9 - The Lithosphere Flashcards
Define: Crust
The solid surface layer of the Earth, made up of plates of the crust that form the continents or the ocean floor.
Define: Resource
The name of a material or the total amount of a material that could theoretically be exploited.
Define: Mantle
The molten and semi-molten layer of the Earth between the core and crust.
Define: Ore
A body of rock that contains minerals that can be exploited.
Define: In Situ
In the place where it is found.
Define: Igneous
Rocks or processes involving molten rock.
Define: Batholith
A large underground mass of solidified molten magma.
Define: Hydrothermal
Processes or deposits associated with hot water.
Define: Regolith
The solid rock particles left after weathering.
Define: Solute
A dissolved substance.
Define: Alluvial
Materials such as soil or weathered rock particles deposited by a river or other flowing water.
Define: Placer Deposits
Deposits of dense minerals carried by water e.g. Tin and gold.
Define: Metamorphic
Rocks changed by intense heat and pressure, but without fully melting.
Define: Sedimentary
Materials or processes that involve material being carried by air or water then deposited.
Define: Reserve
The proportion of a resource that can be economically exploited with existing technology.
Define: Overburden
The unwanted material on top of the mineral deposit that is to be exploited.
Define: Cut-off Ore Grade
The lowest purity of ore that can be exploited economically.
Define: Turbidity
A measure of the cloudiness of water caused by suspended solid particles.
Define: Leachate
Liquids and dissolved materials such as fertilisers washed through the ground, usually downwards.
Define: Core
The solid and molten inner layers of the Earth.
Define: Eutrophication
The natural nutrient enrichment of water body. it can be accelerated by human actions such as the release of sewage effluent or the use of fertilisers that are leached into water bodies.
Define: Homeostasis
The combined processes that maintain balance in a living organism or the environment
Define: Gaia Hypothesis
A theory that considers the Earth to be a single, self-regulating system.
Define: Absorption
The attachment of a material onto a surface.
Define: Detritivores
Organisms that feed on dead organic matter, often in or on the soil, e.g. Earthworms, millipedes and woodlice. They break down dead organic matter that can be further digested by decomposers.
Define: Decomposers
Micro-organisms, including many bacteria and fungi, which break down and digest dead organic matter.
Define: Soil Structure
The characteristics of a soil based on the aggregation of soil particles into peds.
Define: Ped
The basic unit of soil structure where particles of sand, silt, clay and human form aggregates.
Define: Soil Texture
The characteristics of a soil based on proportions of the mineral particles that are sand, silt and clay.
What services and resources does the Lithosphere provide?
- Human exploitable physical resources (fossil fuels, metal ores)
- Biogeochemical cycles (recycle carbon, nitrogen and phosphorous)
- Soil (plant growth medium, habitat for organisms)
What are the environmental impacts of mineral exploitation?
- Exploration (marine seismic surveys cause loud vibrations)
- Land Take (associated buildings, access routes, dumping)
- Habitat Loss (destruction, restoration must be carried out)
> Loss of Amenity (aesthetic problems for local communities) - Pollution
> Dust (blasting/vehicle movements)
> Noise (Mine vehicles/rock blasting)
> Turbid Drainage Water (blocks sunlight, chokes filter-feeding animals)
> Toxic Leachate (kill aquatic life)
> Spoil Disposal (landslides/erosion) - Flooding (collapse of poorly constructed dams)
- Subsidence (poor spoil compaction)
- Traffic Congestion (road traffic and car accidents)
How can the pollution impacts of mineral exploitation be reduced?
- Dust (water sprays)
- Noise (‘baffle mounds’ deflect noise, set blasting times)
- Turbid Drainage Water (holding lagoon where solid settle out)
- Toxic Leachate (filter bed immobilises metal)
- Spoil Disposal (spoil compaction reduce instability)
What are the methods that may be used to extend the lifespan of mineral reserves?
- Mining unexploited reserves
- Increased Exploration
- Better Exploratory Techniques
> Remote Sensing (collecting information without direct contact)
> Gravimetry (strength of gravity, igneous rocks)
> Magnetometry (strength of magnetism, iron ore)
> Seismic Surveys (echoes of surface vibrations)
> Core Sampling (drilling into ground) - Mechanised Mining Techniques (rapid extraction)
- Low Grade Ore Exploitation
- Recycling
- Substitution (abundant material swapped with a rarer material)
What are the major processes in the carbon cycle?
- Photosynthesis (converts low-energy substances into high-energy carbohydrates)
- Respiration (releases energy to drive metabolic processes)
> Aerobic (break down organic compounds)
> Anaerobic (organisms survive in oxygen-deficient environments) - Food Chains (pass organic compounds)
- Fossilisation (incomplete decomposition of organisms)
- Combustion (releases carbon dioxide)
- Volcanoes release carbon dioxide
What are the human impacts on the carbon cycle?
- Combustion of fossil fuels (carbon dioxide increase)
- Coal mines (release methane)
- Combustion of wood (reduces carbon store)
- Anaerobic gut bacteria (release methane)
- Anaerobic bacteria in rice padi fields (release methane)
- Soil disturbance by ploughing (decomposition rates increase)
- Global climate change (decomposition rates increase)
What are the major processes in the nitrogen cycle?
- Ionising phenomena (provide energy for nitrogen and oxygen to react)
- Chemical reduction to ammonia (carried out by micro-organism during nitrogen fixation)
- Food chains (pass nitrogen between organisms)
- Nitrification (oxidation of ammonium ions to nitrites then to nitrates)
- Denitrification (chemical reduction of nitrates)
- Leaching (loss of soluble substances when carried away by water)
- Plant roots absorb nitrogen
What are the effects of human activities on the nitrogen cycle?
- Haber process (industrial fixation of atmospheric nitrogen)
- Nitrate fertilisers use (increase leaching problems)
- Drainage (increases aerobic nitrifying bacteria and reduces aerobic denitrifying bacteria)
- Soil disturbance by ploughing (increases decomposition rates)
- Legumes (increase nitrogen compounds in soil)
- Combustion processes release NOx (increase nitrates washed into soil by rain)
What are the components of soil?
- Mineral skeleton of soil (produced by weathering of rocks, Regolith)
- Air in soil (provides gases for aerobic organisms)
- Soil water (used for physiological functions)
- Living organisms (decomposition, nutrient recycling and aiding drainage)
- Dead organic matter (source of food for soil organisms)
What type of living organisms are found in soil?
- Plants (roots hold soil together)
- Detritivores (break up dead organic matter)
- Decomposers (digest dead organic matter)
- Nitrogen cycle bacteria (nitrogen fixation, nitrification, denitrification)
- Mycorrhizal fungi (provides plant roots with nutrients)
What are the effects of soil properties on soil fertility and productivity?
- Aeration (enables rapid aerobic processes)
- Water drainage/retention (enable nutrient absorption)
- Thermal capacity (retain heat)
- Soil structure (particles aggregate together to form peds)
- pH (ideal soil acidity 5.5 - 6.5)
- Soil texture (affects drainage, nutrient retention and root penetration)
