Rocks

Question 0

3 groups of rocks

Answer 0

• igneous (hot rocks/fire)
• sedimentary
• metamorphic

Question 1

Rocks

Answer 1

-Made up of minerals
-Makes up the geosphere
Most rocks are made of several minerals but some are monomineralic (one mineral)

Question 2

Igneous

Answer 2

Rocks formed by crystallization of magma/lava during cooling

Question 3

Sedimentary

Answer 3

Formed at or near earth’s surface from sediment that may include mineral or rock fragments, organic fragments (sandstone), by precipitation from water (limestone)

Question 4

Metamorphic

Answer 4

Formed from igneous, sedimentary or previously metamorphosed rocks by heating and/or increase in pressure during collision of tectonic plates or magma intrusion

Question 5

Major environment issues associated with igneous activity

Answer 5

• volcanic hazards
• sources of many ore deposits
• driving energy and nutrients for some important ecologic systems
• driving energy for geothermal systems
• building materials

Question 6

Igneous rocks
(intrusive vs extrusive)
(plutonic vs volcanic)

Answer 6

-lava flow (volcanic/extrusive)
-magma chamber (plutonic/intrusive)
Plutonic vs volcanic:
-plutonic (slowly cooled)
-volcanic (rapidly cooled)

Question 7

Igneous rock

Ferromagnesian (dark color)

Answer 7

• olivine
• pyroxene
• amphibole
• biotite

Question 8

Igneous rock

Felsic (light color)

Answer 8

• plagioclase feldspar
• orthoclase feldspar
• Quartz
• muscovite

Question 9

Things that control igneous rock composition

Answer 9

• composition of the source

- magnetic differentiation

Question 10

Provenance of igneous rock composition

Answer 10

• mantle is made of peridotite
• mantle source -> basalt, andesite, dacite (and their plutonic equivalents: gabbro, diorite, granddiorite)
• continental crust source -> rhyolite (and it’s plutonic equivalent: granite)

Question 11

Magmatic differentiation

Answer 11

-process by which a homogenous magma segregates into different rock types

Question 12

Magmatic differentiation: sequential crystallization of minerals permits their separation

Answer 12

High density minerals will sink inside a magma chamber, low density minerals will float inside a magma chamber

Question 13

Fractional crystallization

Answer 13

The separation of minerals, it is the most common type if magmatic differentiation

Question 14

Making of sedimentary rocks

Answer 14

1) weathering
- mechanical (erosion, breaking rocks apart)
- chemical (chemical reactions)
2) sedimentation (transport and deposition)
3) Lithification

Question 15

Weathering

Answer 15

Is the response of rocks to new conditions at or near Earth’s surface
-for example, minerals in lava that crystallized at 1000 degrees Celsius are not very stable at surface conditions

Question 16

Agents of mechanical weathering (erosion)

Answer 16

• running water
• wind
• glaciers and ice
• ocean currents and waves
• gravity

Question 17

Chemical weathering

Answer 17

Dissolution or transformation of original minerals to secondary minerals by interaction with various solutions

• dissolution by water
• dissolution by acid
• oxidation
• hydrolysis (diagenesis)

Question 18

Properties of clay

Answer 18

Good properties:
-filtering of toxic metals
-material for pottery and construction 
Bad properties:
-swelling of soils
-soil failures (slumps, landslide)

Question 19

Factors that control the extent of chemical weathering

Answer 19

1) composition of minerals
2) temperature
3) presence of water (humidity)

Question 20

Weathering-composition of minerals

Answer 20

• ferromagnesian silicates weather the fastest
• K - Al silicate are more resistant to weathering
• Halides and Sulfates dissolve easily in solutions
• carbonates dissolve easily in acidic solutions

Question 21

Weathering-temperature

Answer 21

High temp increases rate of weathering

Question 22

Role of climate

Answer 22

Climate combined the previously noted factors

• in warm, humid climates, chemical weathering predominates
• in arid, cold climates, mechanical weather predominates

Question 23

Transporting sediment

Answer 23

• water (fluvial transport)
• glaciers
• wind (Aeolian transport)
• gravity (Mass wasting)

Question 24

Types of sedimentary rocks

Answer 24

-detrital -chemical -biochemical A sedimentary rock may contain all 3 components

Question 25

Detrital (clastic)

Answer 25

Pieces of pre-existing rocks and minerals litho fief together as solutions pass through and precipitate quarts or carbonate minerals

Question 26

Chemical

Answer 26

Minerals are precipitated from seawater or lakes

Question 27

Biochemical

Answer 27

Components that have biological origin

Question 28

Common detrital sedimentary rocks

Answer 28

1) conglomerate: dominated by rounded granules or larger rock or mineral fragments 2) sandstone: dominated by sand-size grains 3) shale: silt or mud-sized grains

Question 29

Chemical sedimentary rocks

Answer 29

1) limestone- mostly calcite 2) dolostone- 50% dolomite, forms by additions of Mg to calcite 3) evaporites- consist if precipitated halides, Sulfates, borates ect. 4) chert- finely crystalline silica deposited on ocean floor

Question 30

sedimentary rocks with biochemical components

Answer 30

- Coal: converted organic matter, usually from swamps - black shale: shale with carbonized algae - fossil-bearing limestone

Question 31

Metamorphic rocks

Answer 31

Metamorphism: is the response of rocks by solid state reactions and deformation to changes in temperature, pressure and chemical environment

Question 32

Agents of metamorphism

Answer 32

- heat (200-900•c): causes mineral reactions and coarsening, ex: muscovite -> orthoclase + corundum + water - pressure: causes mineral reactions and deformation of rocks - hydrothermal solutions: carry dissolved elements that cause formation of new minerals (metasomatism)

Question 33

Causes of metamorphism

Answer 33

- plate tectonics and mountain building | - intrusion of Magnus into the upper crust

Question 34

Some societal issues of metamorphic rocks

Answer 34

- metamorphism results in the formation of some mineral ores (graphite, talc, ect.) - many gens are metamorphic mineral (ruby, garnet, jade, ect.) - slate and marble are important building stones - metamorphic foliation influences groundwater flow and slope stability

Question 35

Metamorphic foliation

Answer 35

Foliation is alignment of Micas (and other minerals) because of compression. It is common is schist, which contain high proportions of Micas