Unit 6 + 7 Flashcards
Definition of a mineral
Naturally occurring combination of specific elements which are arranged in a particular repeating 3-D structure
What is a rock?
Naturally occurring aggregates (mixture) of minerals
What is silicate minerals?
These are minerals made out of oxygen and silicon. It’s majority of the earths crystal elements.
What are carbonate minerals?
Made out of carbonate ions. There are most common as the mineral calcite marine animals also construct their shells from calcite.
How does cooling rate affect growth?
Fast cooling equals small minerals slow cooling equals large minerals
What is mineral precipitation?
Precipitation from an aqueous solution result in the formation of mineral crystals
What is metamorphism?
The alternation of the composition or structure of a rock or mineral by heat and pressure it forms, new minerals from elements existing in old minerals
What is organic formation?
Minerals formed from biological activity, shells, teeth, and bones
Mineral streak
The colour of the mineral when it’s powdered a better diagnostic than colour
Opacity
The ability to transmit light specifically in this situation through minerals
What is luster?
Describes the quality of light reflected from the surface of a mineral
What is Crystal habit?
The natural shape of individual crystals it depends on crystal structure and growth conditions
What is mineral cleavage?
The tendency for minerals to split along definite plan it’s controlled by the presence of planes and weakness with the crystal structure
What is a mineral fracture?
How minerals break when there are no planes of weakness
What are the two main types of fractures?
Irregular fracture, which is uneven breaking, the surface will have lumps and crevices. And conchoidal fracturing which is circular or semicircular ridges and furrows so more of a smooth texture.
What is exosolution?
This is the process, through which an initially homogeneous solid solution, separates into at least two different crystalline minerals, without the addition or removal of any minerals
What is the rock cycle driven by?
Earths, internal heat, engine, and the hydrological cycle
What is magma?
Molten or semi molten rock under the Earth surface, it takes a very long time to form, and it is an intrusive igneous rock (comes from plutons)
What is lava?
Molten or semi molten rock above our surface and it can cool really quickly and it also forms extrusive igneous rocks (comes from volcanoes)
What is partial melting?
When only a portion of solid material is melted, minerals melted different temperatures, so it may not melt at the same time
What are the two ways to form magma or melt rock?
Decompression melting, which is when the body of rock remains at the same temperature, but the pressure is reduced (it’s moving towards earth surface) and flux melting, which is when a body of rock close to its melting point has an injection of water, which reduces the melting temperature
How does magma move towards the surface?
Because it is less dense than the surrounding rock, it will slowly creep up, as well as it breaks and melts the surrounding rock
What is a pluton?
A body of solid rock formed by the complete cooling or crystallization of a magma body below earth surface
What is phaneritic texture
Igneous rocks, with a large visible crystals
What is pegmatitic texture?
Igneous rocks, with exceptionally large, visible mineral crystals
What is aphanitic texture?
Igneous rocks, with small mineral crystals, creating fine grains texture
What is a glassy texture
Igneous rocks, with no mineral crystals, creating a glass like texture
What is tephra?
Rock fragments, dust, and gas produced during explosive volcanic eruptions. It’s also called pyroclastic rock.
What is porphyritic texture?
This is igneous rocks with both large and small crystals
What does the amount of silica and magma dictate?
How far down the reaction of magma can go so all reactions will stop once all the silicone is used up
What is felsic magma?
This is silica rich so over 65%. This is formed by partial melting of the continental crust. It’s very thick magma at a low temperature and it’s dominated by light coloured minerals.
What is intermediate magma?
This is 52 to 65% silica it’s formed by the partial melting of the continental crust. This magma chamber will pass through the continental crust, and it contains dark and light minerals.
Mafik magma
45 to 52% silica it’s formed by the melting of the mantle and the oceanic crust crystallizes that high temperatures and has a low viscosity magma so it’s runny. It contains dark coloured minerals.
What is fractional crystallization?
Early formed minerals removed from the magma by gravity this results in a base of magma that is Matic mineral rich and the upper magma is Felic mineral rich
What is a volcano
And location where Mema comes to the surface or has done so within the past several million years can be on land or the ocean floor
What are shield volcanoes?
They form from mafic magma, and are runny
What are Strato volcanoes?
Formed from felsic and intermediate magma, these are explosive
What are the two types of mafic lava flow?
Pohoehoe which is smooth, undulating hummocky surface “ropy” as well as A’a rough, and Rubbly surface sharp and jaggered
What is pyroclastic flow?
Fast movie currents of Tafra that flows down the sides of the strata volcano
What is weathering?
Breaking down of of minerals, rocks and soil through contact with water atmosphere gases and biological organisms. There is no movement of material (chemical)
What is erosion
The transportation of minerals rocks, and other material by water, ice, snow, wind, waves, and gravity. There is a removal of material so it occurs offsite
What is mechanical weathering?
The physical breakdown of minerals and rocks into smaller fragments, greatly facilitated by erosion and it is a positive feedback loop
What is exfoliation?
A decrease on confiding pressure on a rock, causing it to expand promotes cracking of the rock which peels almost think of shale
What is frost wedging?
A process by which water and cracks within a rock expands on freezing, thus enlarging the crack
What is salt, crystal growth?
Growth of salt, crystals, exert pressure on the surrounding rocks and push the rocks.
What is biogenic weathering?
Mechanical breakdown of rocks and minerals by plants and animals such as borrowing organisms or roots
What is chemical weathering?
Results from chemical changes to minerals that become unstable when exposed to earth surface it happens in warm, wet climates, and the most important agents are water, oxygen and carbon dioxide
What is dissolution?
A process in which a mineral dissolves completely without producing a new solid substance. It essentially dissolves the rock.
What is hydrolysis?
A chemical reaction where water breaks down chemical bonds only part of a mineral is taken into solution if you don’t shut the fuck up
What is oxidation?
Chemical oxidation of metals so essentially rust
What are the two types of wind erosion
Deflation where the wind picks up small loose particles, and carries them away and abrasion where earth surfaces are worn down as wind blown particles hit the surface
What is regolith?
Loose unconsolidated, rock and debris that sits above a layer of bedrock the in place products of weathering
What are plastic sediments?
They are a product of mechanical and chemical weathering. They are made from fragments of pre-existing rocks.
What is chemical sediment?
The product of chemical weathering, and it’s made from ions precipitated out of solution
M why do you sediments very so much?
Because of the composition and the process of transportation
What is clast
An individual fragment of rock or mineral
What is grain size?
How geologist classify clast
What is sorting?
The distribution or variance of grain size within a sediment
How can you tell if the sediment is mature or not?
They should have very well sorted sediments
What is chemical sediments?
Materials formed by the precipitation of minerals in a solution, such as carbonate shells or salt
What is diagenesis?
The changes that happened to unconsolidated sediments after they are deposited. It is a physical and chemical process and occurs at low temperature and pressure.
What is lithification
The conversion of unconsolidated sediments to sedimentary rocks by diagenetic process
What is compaction?
The burial of loose sediments by subsequently deposited sediments. It drives water out of the poor space and reduces the poor space.
What is cementation?
The crystallization or growth of new minerals within the poor space
What are plastic sedimentary rocks?
These are composed of plastic sedimentary grains, which are made from pre-existing rocks
What are chemical sedimentary rocks
These are composed of minerals, precipitated out of a solution. There are product of chemical weathering.
What are inorganic sedimentary rocks?
This is composed of organic matter, and they’re made from accumulations of plant and animal debris
What is metamorphism?
The alternation of the composition or structure of a rock or mineral by heat and pressure, so it forms a new mineral from elements existing in minerals
What are the main factors that control the metamorphic process?
The mineral composition, the temperature, amount of pressure, the type of fluids, and the amount of time
What is a parent rock?
The rock that exists before metamorphism starts subjected to pressure and temperature previously previously metamorphic rocks cannot be parent rocks
What is metamorphic temperature?
This controls the metamorphosis that occurs temperature increases with increased burial
What is metamorphic pressure
A function of the depth of burial pressure increases with that, however, pressure is not equal in all directions
What can pressure affect?
The type of mineral that will grow as well as the texture
What are polymorph minerals?
Minerals with the same chemical composition, but different internal structures
Rocks under high, confining, pressure are what
More dense the minerals and grains, squeeze together and have a greater density
What can direct pressure and sheer stress result in?
Foliation, which is uneven pressure that elongates minerals in a particular orientation they become aligned to take up less space
What are metamorphic fluids?
These facilitate the transfer of ions between and within minerals, it brings in dissolved ions, and moving elements around the crust and water is the main fluid in metamorphic rock
Are metamorphic reactions, slow or fast
They are extremely extremely slow
What are foliated metamorphic rocks?
These are classified by the grade, and grade, describes the relative temperature and pressure which the rock forms
What are non-foliated metamorphic rocks
They are classified by the composition of the rock, with no elongate minerals to align with pressure, there are only two types, quartzite and marble
What is regional metamorphosis?
Rock minerals are subjected to increase heat and pressure due to burial within the crust high temp and high-pressure
What is contact metamorphosis?
These are rocks altered by the heat of a body of magma that intrudes into the upper crust so it essentially cooks the rock they have no foliation and it’s high-temperature
