Geology

Question 1

Law of superposition

Answer 1

The Law of Superposition states that beds of rock on top are usually younger than those deposited below.

Question 2

Absolute dating def

Answer 2

Absolute dating: Absolute dating is a method used to determine the specific age of a rock or fossil in years, qualitative

Question 3

How is absolute dating usually carried out

Answer 3

through the use of radiometric techniques that measure the decay of radioactive isotopes.

Question 4

Relative dating def

Answer 4

relative dating is a method used to determine the age of rocks or fossils by comparing their positions in relation to other rocks or fossils, quantitative

Question 5

The law of uniformitarianism

Answer 5

the earth has always changed in uniform ways and that the present is key to the past

Question 6

Weathering of rocks must take place

Answer 6

On the surface

Question 7

Sedimentary rocks were likely formed

Answer 7

in water

Question 8

Law of original horizontality

Answer 8

Layers of sedimentary rock are originally deposited flat

Question 9

Law of crosscutting relationships

Answer 9

The cut rock layers are older than the rock that cuts across them.

Question 10

Law of lateral continuity

Answer 10

Rock layers extend laterally until they encounter other solid bodies that block their deposition or acted upon after deposition

Question 11

unconformity

Answer 11

a break in time in an otherwise continuous rock record

Question 12

Fold

Answer 12

undulation or waves in stratified rock, caused by pressure that uplifts

Question 13

Fault

Answer 13

a fracture or discontinuity in the Earth’s crust where rocks on either side have moved relative to each other,

Question 14

Index fossil

Answer 14

a fossil that is useful for dating and correlating the strata in which it is found.

Question 15

A useful index fossil

Answer 15

easily recognizable, abundant, and have a wide geographic distribution and a short range through time.

Question 16

Radioactive isotopes are

Answer 16

isotopes that are unstable and break down into other isotopes by a process called radioactive decay.

Question 17

The radioactive isotope is called

Answer 17

the parent isotope,

Question 18

and the stable isotope formed by its breakdown is called

Answer 18

the daughter isotope.

Question 19

Half-life is

Answer 19

time needed for half of a sample of a radioactive element to undergo radioactive decay and form daughter isotopes.

Question 20

Once a plant or animal dies

Answer 20

No carbon 14 can enter

Question 21

Who proposed the theory of Pangaea

Answer 21

Alfred Wegener

Question 22

Continental drift

Answer 22

Over millions of years, the continents slowly drift into their present-day positions.

Question 23

tectonic plates def

Answer 23

gigantic pieces of the Earth’s crust and uppermost mantle

Question 24

Contiental drift theory how

Answer 24

The Jigsaw Fit
Fossil correlation
Rock and Mountain correlation
Paleo climate correlation

Question 25

What is missing from his theory

Answer 25

There is no mechanism for how the continents could shift

Question 26

How was contiental drift mechanism found

Answer 26

Hess’ theory of seafloor spreading, lava from the earth’s mantle pushes the oceanic crust apart

Question 27

Mid Ocean Ridges

Answer 27

Underground mountains formed by the solidification of underwater lava

Question 28

Ocean trenches

Answer 28

when one plate goes under the other

Question 29

Age of seafloor

Answer 29

Further rocks are from ridges the older they are

Question 30

Convection Current (in the mantle)

Answer 30

Circulation patterns that occur as dense rocks sink and less dense rocks rise

Question 31

Tectonic plates move

Answer 31

relative to each other

Question 32

Oceanic crust

Answer 32

Crust that forms the Oceanic basin
More dense than continental crust
Gets recycled through subduction, younger

Question 33

Continental crust

Answer 33

Crust that forms the contients
Less dense than oceanic crust
Doesn’t get recyled, older

Question 34

The rocks formed from the mid ocean ridge (magnetic)

Answer 34

preserve the magnetic polarity, creating a rock record of it

Question 35

Plate Boundaries are

Answer 35

The places where tectonic plates meet

Question 36

Transformative/conservative boundaries are characterised by

Answer 36

the parralell sliding of plates, they move slowly and then ‘slip’ (san andreas)

Question 37

Divergent boundaries are characterised by

Answer 37

The Spreading of plates moving away from each other, creates mid ocean ridges (iceland)

Question 38

Convergent boundaries are characterised by

Answer 38

the collision of plates, one will slip beneath the other, creating a trench or subduction zone, or a mountain (himalaya mountains)

Question 39

In convergent boundaries, which is more likely to subduct

Answer 39

The older, as it is most likely more dense

Question 40

Why do tectonic plates move

Answer 40

1. Friction between the convection cell and the tectonic plates is strong enough to move it
   2

Question 41

Why is oceanic crust thinner

Answer 41

it is recycled more and doesn’t have chance for a lot of sediment to deposit on it.