Lecture 3- Minerals And Rocks Flashcards
What are the three classifications of rocks
Igneous, Sedimentary and Metamorphic
What are igneous rocks? What are a few of their properties?
Rocks formed when molten material/magma or lava cools and solidifies. They appear to have crystals and are NEVER layered.
What are the two types of igneous rocks?
Intrusive and extrusive igneous rocks
What are sedimentary rocks?
Rocks formed from sediments, bits of preexisting rocks and pieces of once-living organisms (ex: mollusks and other invertebrates
What are 3 properties of sedimentary rocks
-Have layers
-Feel gritty (fought texture/feels like it is coated in sand
-Often break easily
give 3 examples of sedimentary rocks
- chalk
- coal
- sandstone
(see ppt slide 3 for more)
What are metamorphic rocks?
Igneous or sedimentary rocks that have been transformed by high pressure, high heat, and/or contact with hot magma
Where are metamorphic rocks found?
-Deep in the earth
-Where tectonic plates meet
give 3 examples of metamorphic rocks
- marble
- slate
- soapstone
True or False: Metamorphism melts rocks
FALSE. It just turns them into denser rocks (more compact)
Where does molten rock/magma (that will later form igneous rocks) originate within the earth?
-Tectonic Plate Boundaries
-Hot spots
How are intrusive igneous rocks formed
Magma trapped below the surface cools slowly, solidifying over thousands or millions of years
What is another way of naming intrusive igneous rocks?
Plutonic igneous Rocks since Pluto= Ancient Roman god of the underworld
Why does mineral crystal in intrusive igneous rocks have time to grow to larger sizes?
It cools slowly
What is the texture of intrusive igneous rocks
Coarse Grained Texture (crystals are visible)
give 4 examples of intrusive igneous rock
- diorite
- granite
- gabbro
- pegmatite
Why do the first crystals have more regular shapes?
Because they can grow more freely into surrounding molten rocks
Why do later forming crystals have weirder shapes?
Because they are forced to fill irregular spaces remaining between previously solidified/neighbouring minerals.
What happens with extrusive rocks?
They form when Magma/lava exits a volcano or rises up to surface through a fissure.
give 4 examples of extrusive igneous rocks
- basalt
- andesite
- scoria
- rhyolite
What is a fissure
À crack/fracture in the rock
Where does magma cool when it exits the volcano
Right above or very near to the earth’s surface
Why does the magma/lava begin to cool/solidify instantaneously when it leaves the volcano?
Because of the cooler temperatures at the surface (than when they were underground) They are shocked
What is an extrusive rock with a glassy texture
Obsidian
What is the texture of extrusive igneous rocks
Fine grain texture (crystals are too small to see with naked eye)
What does it mean when extrusive igneous rocks have a glassy texture
They do not contain mineral crystals
What is an example of a rock with gas bubbles trapped within
Scoria
Pyroplastics/scoria rocks are released by what kind of volcanoes?
???
What is a rock?
A naturally occurring solid mass/object made of one or more geological materials
Geological materials inclue what? (4)
- Mineral crystals
- non mineral solids
- bits of other rocks
- fossils
What is the difference between organic and inorganic geological materials?
Organic= have carbon and carbon-hydrogen bonds
Inorganic= Generally no carbon and definitely NO carbon-hydrogen bonds
What is a crystal
Solids whose atoms/molecules/ions are arranged in a “highly ordered” repeating pattern. They have a highly ordered MICROSCOPIC arrangement of atoms
True or false: All solids are crystalline solids
False, not all solids are crystalline solids
What is a non-crystalline rock called and what does it mean
It is called amorphous, a substance whose atoms are NOT arranged in a “highly ordered pattern”
What is an example of a solid igneous rock that is non-crystalline
Obsidian
What is the name of solids that have atoms with highly ordered repeating pattern
Crystalline solids
What is crystallization
Process by which crystals form and grow
True or False: Macroscopically, crystals have specific geometric shapes with flat surfaces
True
What are three crystals
SiO2 (quartz) NaCl (Halite) and H2O (water)
What is a mineral (6 things)
1) Inorganic
2) Naturally occurring
3) Homogenous solid
4) with definite chemical composition
5) and ordered/crystalline atomic structure
What does inorganic mean?
-Not made up of living matter
-Not derived/originating from living matter
Not made up of organic materials (organic materials= carbon or carbon-hydrogen bonds)
What are two conditions for something to be naturally occurring:
-must be formed/occur naturally
-cannot be human-made or manufactured from a lab
What is MICA (4 things)
-a silicate mineral
-individual mica crystals can be split into thin elastic sheets
-MICA common in igneous and metamorphic rocks
-Silicates are combination of silicon and oxygen
what is silicate
combination of silicon and oxygen
What is a homogenous solid? (5)
-Solid
-Chemically uniform (same substance throughout)
-physically uniform (same appearance throughout)
-same crystals/organication of atoms/molecules/ions throughout
-Observe same things microscopically and macroscopically throughout the sample
TALC: (4 things)
-A silicate mineral
-TALC is the “softest” mineral
-Used to make baby powder in powdered form
What is pyrite (fool’s gold) (4 things)
- FeS2
-Most abundant sulfide mineral
-sulfide minerals are minerals containing S2- ion
-Pyr = Greek for fire. Pyrite emits sparks when struck with metal
