Quarter 2 Quiz 1 Flashcards
3 ways to melt rock
Adding heat - Increase temperature, add enough heat and you melt rock
Reducing pressure - also called ‘decompression melting’, this occurs when rock is under lots of pressure and that pressure is suddenly released
Adding water - adding water to rock weakens bonds and lowers the melting point by a bit…water acts as a ‘network modifier’
Temperature and viscosity of different types of Magma (mafic and felsic)
Felsic magma is more viscous, felsic magma is less hot because it forms shallower than mafic magma
Mafic magma is less viscous, mafic magma is hotter because it forms deeper than felsic magma, in the upper mantle
Magmatic differentiation
Rocks of varying composition can arise from a uniform parent magma and ice versa
Process is a result of the fact that minerals have different crystallization (melting) temperatures
Once partial melt forms, it can migrate upwards, leaving the solidified minerals behind (precipitate)
Migrating partial melt can pool in magma chamber, and then eventually erupt
As the temperature of the magma changes, it can form different rocks
Intrusive
Rocks that are formed when magma cools slowly into rock below the surface, allowing larger crystals to form (more coarse texture)
Coarse-grained rock is called a phanerite.
Extrusive
Rocks that are formed when lava cools rapidly into rock above the surface, allowing insufficient time for larger crystals to form (finer texture)
Fine-grained igneous rock is called an aphanite
Extrusive - Glassy
Atoms lack time to organize themselves into minerals
A mineraloid forms instead (mineral-like solid that lacks either a crystal structure or a definite composition or both)
less time than normal extrusive rocks
magma vs. lava
magma when below ground, lava when above ground
Vesicular rocks
Rocks with air pockets (holes) are known as ‘vesicular’, occurs when gas is trapped in the magma, always extrusive
Basaltic magma
has low silica content and low viscosity, meaning it flows quickly
Rhyolitic magma
high in potassium and sodium, but low in iron, magnesium, and calcium
What is an igneous rock
Rocks that form when rock is melted and re-hardens
A rock must be melted and recrystallized to produce an igneous rock
Rock cycle (in basic terms)
The rock cycle describes the gradual ongoing process by which rocks are changing
Rocks change between being igneous, metamorphic, and sedimentary
Mineral definition
SINAC
Solid, Inorganic (minerals are not produced by organic processes, not leaves, etc.), Naturally occurring, fixed Atomic Arrangement (crystal lattice), fixed Chemical Composition (formula)
Mineral properties are mostly determined by
The internal arrangement of atoms in the mineral
Chemical composition - ion substitution
Not quite all minerals have a fixed chemical composition, sometimes atoms with similar atomic radii can substitute out for one another, called ion substitution
Internal structure > chemical composition
Crystalline structure
Minerals are the result of atoms joining together through electrical bonds to produce a definite internal structure
It is the nature of the atoms and the strength of the chemical bonds that determine many of the minerals’ physical and chemical properties
Mineral resources (ores, mining, etc.)
A number of minerals are valuable to society, either by themselves or by extracting important metals
Ex. gems and precious metals, metals used in electronics and industry, construction, minerals in soil
Metal sulfide ores(others: tin, nickel, aluminum)
Ore def and info
A naturally occurring solid material from which a metal or valuable material can be profitably extracted
Mined from underground (tunnels and shafts), surface (open pits or mountain top removal), or placer (riverbank gravels) deposits
Major groups of minerals
Silicates, oxides, sulfides, and native elements
Silicates
Any mineral with silica and oxygen, most common minerals, ex. quartz, mica, feldspar
Most common minerals
Oxides
A metal with an oxygen, ex. Hematite, Sapphire
Sulfides
Any metal bonded to a sulfur, ex. pyrite, galena
Native elements
things that exist on their own, ex. Gold, silver, sulfur
Polymorphism
2 minerals with the same composition can be very different due to their structure
describes how two minerals can have the same chemical composition and be considered different minerals
why do we care about minerals?
Everything we use on Earth comes from Earth
Minerals are an extremely important economic and technological resource for humanity
Mineral ID (what traits are the most reliable and the ESRT)
Physical properties - color, luster, streak, hardness, cleavage or fracture, density, magnetic, reaction with HCI
Streak
Streak - the color of the mineral in powdered form
Fracture/cleavage
Cleavage is the tendency of a mineral to split along one or more smooth, flat surfaces. If a mineral does not display cleavage, it is fracture, and breaks unevenly
Luster
Either metallic or nonmetallic
Hardness
The mineral’s resistance to being scratched/ability to scratch
Rocks vs. minerals
Both are solid, both are naturally occurring
Rocks
Solid mixtures of minerals
Might be organic or have organic components
Minerals
Can be expressed by chemical formula
Has definite crystal structure
Hardness of glass
hardness of fingernail
Hardness of glass is 5.5
hardness of fingernail is 2.5
about how many mineral ‘species; have been discovered?
About 6000
Aphanite
extrusive rocks
Phanerite
intrusive rocks
