2. Rocks, Minerals and the Rock Cycle Flashcards
(39 cards)
Outline the five states of the rock cycle.
- Magma
- Igneous rock
- Sediment
- Sedimentary rock
- Metamorphic rock
What are rocks?
The aggregate of minerals
What are minerals?
Naturally-occurring pure substances of a specific chemical composition.
What are crystals?
An inorganic solid composed from a repeated molecular structure.
What are the three main rocks?
- Igneous
- Sedimentary
- Metamorphic
What are igneous rocks?
Rocks formed from the cooling of magma.
What are the three ways igneous ores can form?
- Solidification.
- Cooling.
- Volcanic emissions.
What are sedimentary rocks?
Rocks which have been formed from the compaction of sediment. Sedimentary rocks cannot be dated as they are formed from multiple different rocks.
Can sedimentary rocks be dated?
Yes, but the results are not trustworthy.
What are the three types of sedimentary rock?
- Clastic - Made from rock fragments.
- Chemical - Formed from precipitation of solutions.
- Organic - Deposited by living organisms.
What are metamorphic rocks?
The bridging gap between solid and liquid state
What is Mafic lava?
Thin layers of lightly-coloured lava commonly found in mid-ocean ranges. Because Mafic rocks are lighter in texture, they result in weaker eruptions which is most commonly traced to their lacking silica content. Mafic lava creates basalt.
What is Felsic lava?
Thick, darkly-coloured lava commonly recovered in convergent zones. Mafic lava eruptions are chaotic, as their high silica content results in great explosions. Felsic eruptions are dark in colour and create rholite.
What are the silicates?
A compound of silicon and oxygen found in many igneous rocks. Silicates are the most common minerals on the earth.
What is the principle for crystal formation?
The faster a crystal forms, the smaller the crystals formation size is.
What are the five characteristics of rock classification?
- Colour
- Hardness (strength)
- Lustre (shine)
- Streak (strength)
- Cleavage/fracture (how the rock breaks)
What are ore bodies?
The sum total of multiple ore minerals. Ore bodies are used, but only to extract materials such as metal.
What is the ore grading system?
The ore grading system determines the quality of an ore based on remaining oil deposits.
What are the four main ore deposits?
- Magmatic ore deposits.
- Sedimentary ore deposits.
- Metamorphic ore deposits.
- Hydrotherminal mineral resources.
What are magmatic ore deposits?
Ore formed through igneous processes such as;
- Exhalative ore deposits (When volcanic material is extruded onto the earths surface through hydrothermal vents)
- Intrusive ore deposits (magma cools within the oceaning or continental crust, below the earths surface)
What are sedimentary ore deposits?
Ores deposited inn a sedimentary environment. Sedimentary ore deposits are formed through :
- Chemical precipitation.
- Placer deposits.
Why are zircon crystals important in rock dating?
Zircon crystals are able to survive natural processes such as erosion and weathering, which has resulted in different levels of damaging symbolic of different time periods. Additionally, zircons contain trace amounts of thorium and uranium which can be used for uranium 238 dating.
How can meteorites be used to understand the structure of the earth?
Meteorites were formed from the same geological process as earth thus meaning that meteorites were formed from similar materials. Being significantly smaller than earth, materials can be extracted from meteorites to determine what elements are in the deep layers of the earth.
Furthermore, seismic activity can be used to determine a broad understanding of the materials P and S waves travel through.
What are the three main classifications of rocks in Aboriginal culture (give an example for each).c
- Food gathering (quartz)
- Artistic pursuits (Ochre)
- Food grinding (pebbles)
