Topic 2 - The Lithosphere Flashcards
(30 cards)
What are the layers of the Earth?
-The crust (8-40km)
-The mantle (2,900km)
-The outer core (2,250km)
-The inner core (1,300km)
State a few examples of metals/metal ores and their uses.
Iron ore - used to produce steel, essential in construction
Copper ore - used in electrical wiring and plumbing.
Lithium ore - used in rechargable batteries
State examples or industrial minerals and their uses.
Limestone - used in the production of cement, glass and steel
Gypsum - used in the production of plaster, wallboard, and cement
State examples of construction materials and their uses.
Sand, gravel, and crushed stone - used in concrete production and road construction
Clay - used in the production of bricks, tiles and cement
Give the definition of a non-renewable resource.
A natural resource that cannot be replenished or regenerated on a human timescale. Once these resources are extracted and used, they are not readily replaced. Because they may take millions of years to form, their supply is finite, and they are considered exhaustible.
What is hydrothermal deposition?
An igneous process (a process involving magma/molten lava):
-Magma can intrude into the crust, where it cools and solidifies.
-The intrusions superheat water to high temps and pressures
-This dissolves minerals dispersed within the rock
-When cooling, the dissolved minerals crystallise
-This causes minerals that were present as a mixture to separate, and form concentrated deposits.
What is metamorphism?
The process by which rocks are transformed due to changes in temp, pressure, and chemical environment without the rock melting. Metamorphism can lead to the recrystallisation of minerals and the formation of new minerals.
What is contact metamorphism?
Rocks are heated by nearby magma or lava. This can lead to the formation of skarn deposits, rich in minerals such as garnet, magnetite, and tungsten.
What is regional metamorphism?
Large-scale deformation and recrystallisation of rocks due to tectonic forces. Results in the formation of minerals like graphite, talc, and asbestos.
What is proterozoic marine sedimentation?
-During the proterozoic eon (2.4 billion to 540 MYA), extensive marine environments existed where sedimentation processes were active.
-The evolution of organisms (cyanobacteria, etc) led to increasing concs of oxygen
-The O2 reacted with dissolved metal ions in the seawater to form insoluble metal oxides, which precipitated out of solution and settled as sediments.
What is alluvial sedimentation?
-Alluvial mineral deposits form through the processes of erosion, transportation, and deposition by flowing water.
-Rocks are broken down into smaller particles through weathering/erosion
-The eroded particles are transported with flowing water.
-As water slows down, sediments are deposited. The sediments settle in layers, with heavier particles like gravel/sand depositing first, followed by finer particles like silt and clay.
What is chemical sedimentation?
Chemical sediments occur when minerals dissolved in water are precipitated as solids for a variety of reasons.
-As water evaporates, the concentration of dissolved minerals increases
-Changes in temp/pressure can cause minerals to crystallise out of solution.
-Chemical changes, such as a change in pH of water can cause the metal’s oxidation rate (charge) to change, turning it from being soluble to being insoluble.
What is biological sedimentation?
This refers to sediments that are formed from the remains of living organisms, such as plants and animals. These can include materials such as shells, bones, and plant fibers. It can occur through the accumulation of organic material, compaction and cementation (buried by additional layers of sediment)
Define mineral stock.
The total amount of a mineral in the lithosphere.
Define a mineral deposit.
A natural concentration of a mineral in the lithosphere, often with a high enough concentration of the mineral to be economically viable for extraction.
Define an ore.
A natural rock or sediment containing valuable materials that can be extracted profitably.
What is an ore grade?
The concentration of valuable minerals within an ore. It is typically expressed as a percentage or grams per ton, indicating the quality and economic viability of the ore for extraction. This can be quite low.
What is the cut off ore grade (COOG)?
The minimum concentration of valuable minerals in an ore that makes it economically viable to process and extract.
What is a mineral resource?
All the material that is theoretically available for exploitation, including deposits that can be exploited currently plus those that cannot be exploited now but may be extracted in the future if the market value or available technology make this feasible. The size of the resource will change over time as exploration work etc gives more data.
What are mineral reserves?
The smaller subset of a mineral resources deemed currently economically viable for extraction at the current market value using existing technology. While mineral resources have potential economic value, the viability of extracting those minerals depends on factors such as market prices, extraction costs etc. They are the portion of resources that a business could realistically and economically mine now.
State Lasky’s principle.
As the purity of available mineral deposits declines in a linear fashion, there is a logarithmic increase in the amount of material present.
What is satellite imagery?
Data collection by remote sensing. The imaging techniques include visible (high definition maps of the earths surface), near infrared (identifying vegetation health and soil moisture), thermal infrared (mapping surface temp variations to identify mineral deposits) etc.
State example satellites for satellite imagery.
Landsat 8 and 9 - provide multispectral and thermal infrared imagery.
Sentinel-1 - uses radar for structural mapping
What are seismic surveys?
Data collection by in-situ sensing. There can be generation of seismic waves (shockwaves in the ground are generated at specific locations using controlled sources), detection of seismic waves (geophones are used to detect reflected seismic waves) and data interruption (recorded data is processed to create cross-sectional images of the subsurface structures)
