Lecture 17

Question 1

Mineral

Answer 1

Naturally occurring inorganic compound with a characteristic crystal structure.
EX: quartz, SiO2; crystal structure is a hexagon.

Question 2

Intrusive igneous

Answer 2

Solidified below surface. Slow cooling - bigger crystals.

Question 3

Extrusive igneous

Answer 3

Solidified at surface. Fast cooling - small crystals.

Question 4

Clastic sedimentary rocks

Answer 4

Made of particles (clasts), mostly of other rocks.
Shale - siltstone - mudstone - sandstone - conglomerate.
Exception; clastic limestone (made of skeletons/shells of living things).

Question 5

Chemical sedimentary rocks

Answer 5

Material dissolved in water become solid (precipitates), accumulates and forms rock.

Question 6

Evaporites

Answer 6

Becomes solid when water evaporates (rock salt, gypsum).

Question 7

Organic sedimentary rocks

Answer 7

Formerly living tissue.

EX: coal; plant remains buried in swamp and modified over time.

Question 8

Metamorphic rocks

Answer 8

One rock changed into another by heat and/or pressure.

New minerals.

Question 9

Regional metamorphism

Answer 9

Deeply buried rock under high pressure and heat.

Question 10

Contact metamorphism

Answer 10

Contact with magma

Question 11

Rock cycle

Answer 11

Rock material changes from one form to another.

SEE CHART.

Question 12

Chemical weathering

Answer 12

Alteration of minerals.
Water is important in some kinds of chemical weathering; wetter environments typically have more than dry ones.
Temperature also important; warmer = faster chemical reactions.

Question 13

Chemical stability

Answer 13

How easily a mineral is altered.

EX: quartz; very stable. Olivine; relatively unstable.

Question 14

Solution

Answer 14

Minerals dissolved in acidic water.

EX: limestone is most common.

Question 15

Hydrolysis

Answer 15

Water broken up, hydrogen ions replace metals in minerals. Created clay minerals (new mineral, very stable).

Question 16

Oxidation

Answer 16

Modifies iron and aluminum to produce oxides (like rust). Red soils to do oxidation.
Oxides are new mineral and are stable.

Question 17

End products of chemical weathering

Answer 17

Stable minerals (like quartz), oxides, clay minerals, soluble ions (soluble ions leave, others remain as parent matter of soils).

Question 18

Physical weathering

Answer 18

Breaking down of rocks into peaces.

Based on internal or external forces.

Question 19

Internal expansion

Answer 19

Intrusive igneous rocks formed at higher pressure than at the surface, so expand when they get to surface.

Question 20

Exfoliation

Answer 20

Example of internal expansion.

When outer layer of granite/rock flakes off.

Question 21

Frost action

Answer 21

Water freezes in cracks, exerts force on rock.

Number of freeze/thaw cycles are important.

Question 22

Salt crystal growth

Answer 22

Salt crystals form when salty water evaporates.

Question 23

Igneous rocks

Answer 23

Formed by cooling of magma.

Classified by mineral content and texture (crystal size).

Question 24

Sedimentary rocks

Answer 24

Material accumulates and solidifies.