Historical Geology

Question 1

Uniformitarianism

Answer 1

everything that can be observed as happening in the world now, has always been happening throughout history

Question 2

Superposition

Answer 2

Newer rock is laid on older rock, so you can determine how old rocks are relative to one another

Question 3

Original Horizontality

Answer 3

rock was originally laid down horizontally, and any deviations depict tectonic activity

Question 4

Original Lateral Continuity

Answer 4

If there is a rift, rock that lies in a horizontal plane were laid down at the same time

Question 5

Crosscutting Relationships

Answer 5

Intrusions in rock determine relative age, meaning the intrusions are younger

Question 6

Difference between a rock and mineral

Answer 6

Mineral: naturally occurring with a definite chemical composition and crystal structure Rock: aggregate of different minerals without a definitely composition

Question 7

Difference between a clastic rock and carbonate rock

Answer 7

clastic rocks are combinations of pieces of other rocks, while carbonate rocks are usually biogenic

Question 8

physical weathering

Answer 8

changing of a surface through erosion or general change of physical properties

Question 9

chemical weathering

Answer 9

change to a substance via actual chemical change; something that is usually irreversible

Question 10

permineralization

Answer 10

water flows through dead organic matter and precipitates fill the voids of cells, retaining internal structure

Question 11

replacement

Answer 11

original mineral has been dissolved away and replaced by a different mineral.

Question 12

recrystallization

Answer 12

original mineral recrystallizes. such as aragonite to calcite

Question 13

carbonization

Answer 13

all volatiles in a substance are driven off by compression and heat, leaving behind a carbon film on a rock, etc. Usually under right conditions

Answer 14

less than 10% fossils in rock, mostly composed of mud. Not organically bound

Answer 15

more than 10% fossils in rock, composed of mud. not organically bound

Answer 16

contains mud, reefs, large amounts of fossil

Answer 17

does not contain mud, completely bound by grains, large grains, mostly fossils

Question 18

Framestone

Answer 18

coral reefs, organically bound by organisms while they are alive, high energy environment

Question 19

bindstone

Answer 19

sponges, organically bound, high energy environment. organisms that bind

Question 20

bafflestone

Answer 20

organically bound by organisms, high energy environment

Answer 21

• Calcite
• CaCO3
• definite crystal structure

Answer 22

• Aragonite
• unstable, breaks down easily to form Calcite
• CaCO3, yet different crystal structure

Answer 23

• Dolomite
• CaMg(CO3)2
• doesn’t effervesce

Answer 24

• Siderite
• Shiny, or oxidized iron
• angular, small grains

Answer 25

• Halite
• NaCl
• Evaporated, salty environment, warmer waters

Answer 26

• Gypsum
• Colder evaporative environment

Answer 27

• Anhydrite
• Coarse, extreme and angular grains

Answer 28

• Chert
• SiO2
• higher latitude, colder waters
• varying colors

Answer 29

• Quartz
• random cleavage plane
• takes up other colors
• extremely fine grained
• light

Answer 30

• Hematite
• red
• medium grained
• red = oxidized iron

Answer 31

• K-Feldspar
• Pink because of K
• three-plane cleavage

Answer 32

• Conglomerate
• Rounded, large grains
• found at river heads

Answer 33

• Arkosic Arenite
• Feldspar present (hand lens)
• three-place cleavage in feldspar