Exam 1

Question 1

What are the characteristics that fulfill the definition of a mineral?

Answer 1

Naturally occurring
Inorganic
Solid
Forms a crystalline structure
Chemically homogeneous

Question 2

What are the definitions of the common physical properties used for identifying minerals?

Answer 2

extrusive - cooled above the surface (volcanic)
intrusive - cooled below the surface (plutonic)

Question 3

What are the relative abundance of major elements in Earth’s crust?

Answer 3

Silicon and oxygen

Question 4

What is meant by the rock cycle?

Answer 4

The rock cycle is the how material in the earth goes through the process of forming into different types of rocks
The life cycle of rock and minerals

Question 5

What is magma?

Answer 5

molten rock below the surface

Question 6

What is lava?

Answer 6

molten rock above the surface

Question 7

What is the source for magma?

Answer 7

water within oceanic crust is brought into the mantle in a subduction zone. water is released into the surrounding hot mantle rock at a depth of about 100km and promotes melting

Question 8

What are the mechanisms that trigger rock to melt at depth?

Answer 8

a decrease in pressure will allow rocks to melt
magma with more water will remain a liquid at a lower temp
heat transfer

Question 9

What are the different magma types?

Answer 9

Mafic
Intermediate
Felsic

Question 10

How do the different magma types compare in composition?

Answer 10

Mafic - dark colored minerals
Intermediate - mix of light and dark minerals
Felsic - light colored minerals

Question 11

What are the different processes that can affect a magma’s final composition?

Answer 11

Assimilation - new minerals are added to the magma from surrounding country rock
Magma Mixing - magma chambers combine together
Partial Melting - induce melting of solid rock
- minerals with higher silica content melt first
Fractional Crystallization - crystals form from magma cooling and settle to floor of chamber

Question 12

Know major points of Bowen’s Reaction Series

Answer 12

dark colored minerals are the first minerals to crystallize
light colored minerals are the last minerals to crystallize

Question 13

How are igneous rocks classified?

Answer 13

Magma types: Mafic, Intermediate, Felsic
Texture: extrusive and intrusive

Question 14

What are the forms chemical weathering?

Answer 14

Dissolution
- minerals dissolve in water
- salts and carbonates are susceptible
- H2O acidity can be important
Hydrolysis
- the replacement of cations in mineral structures using H+ ions
- affects silicates
Oxidation
- minerals react with oxygen to form an oxide

Question 15

What are the forms of physical weathering?

Answer 15

Decrease in pressure - results in expansion
Frost - expansion with water and ice
Roots - can work into the fractures and make them bigger
Salt - mechanical weathering of granite from salt on coastline

Question 16

What are the major clastic sedimentary rocks?

Answer 16

Shale
Siltstone
Sandstone
Conglomerate

Question 17

How are clastic sedimentary rocks classified?

Answer 17

grain size
sorting
roundness

Question 18

What are the major chemical sedimentary rocks?

Answer 18

Evaporites - halite, gypsum
Chemical Limestone (travertine)
Biochemical Limestone
Chert - microcrystalline silica
Coal

Question 19

How do chemical sedimentary rocks form?

Answer 19

Evaporites - precipitate when water evaporates
Chemical Limestone - precipitation of calcium carbonate from ground and surface water
Biochemical Limestone - calcium carbonate becomes incorporated into marine organism shells and skeletons
Chert -
Coal - a sedimentary rock derived from plant remains

Question 20

What are the sedimentary environments where particular sedimentary rocks are found?

Answer 20

Alluvial Fans - poorly sorted
Fluvial (river) Environment
Desert
Delta
Clastic coastlines
Lakes
Glacial Environments
Shallow marine environment

Question 21

What causes rocks to metamorphose?

Answer 21

heat and/or pressure of an existing rock(protolith)

Question 22

What are the different things that can happen to a rock when it undergoes metamorphism?

Answer 22

Neocrystallization - growth of new minerals that are different from the starting rock; atoms migrate or diffuse through solid crystals and/or dissolve and re-precipitate at grain boundaries
Recrystallization - change the shape and size of grains, but not the mineral identity
Phase changes - mineral changes into another mineral with same composition but different crystal structure
Pressure solution - minerals prefentially dissolve at grain boundaries where stress occurs
Mineral migration/remobilization
Physical changes - deformation, rotation, shearing

Question 23

How are metamorphic rocks classified?

Answer 23

Foliated
Non-foliated

Question 24

What is foliation?

Answer 24

directed pressure/differential stress
directional/parrallel alignment or banding

Question 25

What is metamorphic grade?

Answer 25

is the difference in the amount of heat and pressure occur on a rock

Question 26

What are the different types of metamorphism?

Answer 26

Contact - application of just heat Regional - application of heat and pressure

Question 27

Qualities of the core

Answer 27

Outer core - liquid Fe and Ni - density 10-12 g/cm^3 Inner core - solid Fe and Ni - density 13 g/cm^3

Question 28

Qualities of the mantle

Answer 28

- peridotite composition (~40% SiO2) - ~2800 km thick - density 3.3-6 g/cm^3 - ~80% of Earth's mass and volume

Question 29

Qualities of the crust

Answer 29

made up of the continental and oceanic crust oceanic crust is thinner and more dense than continental crust

Question 30

Qualities of the lithosphere

Answer 30

solid (rigid) crust + upper mantle

Question 31

Qualities of the asthenosphere

Answer 31

solid (but deformable) 1-2% molten

Question 32

Qualities of the continental crust

Answer 32

- granitic composition (60-70% SiO2) - density ~2.7 g/cm^3 - 20-70 km thick

Question 33

Qualities of the oceanic crust

Answer 33

- basaltic composition (~50% SiO2) - density ~2.9 g/cm^3 - 4-7km thick

Question 34

What are the concepts of the continental drift hypothesis?

Answer 34

Continental fit Glacial Deposits and evidence of ice sheets on multiple continents Matching geology (only certain geology can be found in certain areas where the continents are not now) Matching fossils Magnetic declination and inclination (with the direction of rocks going towards the magnetic pole and changing)

Question 35

What are the concepts involved in seafloor spreading

Answer 35

is the mechanism to move the continents was discovered through the mid-oceanic ridge 2 oceanic plates moving apart and the space being filled with magma and cooled which forms a ridge Also the age of the ocean crust

Question 36

What are the characteristics of convergent plate boundaries?

Answer 36

Ocean crust subducts beneath continental crust and melts Forms volcanic chains and produces earthquakes Continental crust will not subduct When 2 continental crusts collide, they for a mountain chain

Question 37

What are the characteristics of divergent plate boundaries?

Answer 37

Also called spreading boundary, mid-ocean ridge, or ridge Plates move apart from one another New ocean crust forms Forms a mid-oceanic ridge Results in the formation of ocean basins

Question 38

What are the characteristics of transform plate boundaries?

Answer 38

Also, called Transform fault Plates slide past one another No ocean crust is consumed or generated Produce just earthquakes

Question 39

What are the characteristics of hot spots?

Answer 39

a stationary mantle plume that has burned a hole in the crust and produces volcanism as the plate drifts over it Ex) Yellowstone

Question 40

What are the characteristics of continental rift systems?

Answer 40

a divergent boundary initiated on a continent if they are successful, they eventually produce an ocean basin

Question 41

How has paleomagnetism and polar wander curves contributed to the theory of plate tectonics?

Answer 41

When igneous rock cool, they align with the Earth's magnetic field. Scientist saw how the diploes of rocks where facing and used magnetic declination and inclination to see how the magnetic pole has changed and showing how the plates would have moved.