Geologic Time

Question 1

Says when rock is older or younger, but no age in years

Answer 1

Relative dating

Question 2

Gives age of rocks in years

Answer 2

Absolute or Chronometric Dating

Question 3

States that:

In a series of layers of rocks (unless something weird happens),

The oldest layer is at the bottom
And the youngest at the top.

Answer 3

Steno’s Law of SUPERPOSITION

Question 4

When sedimentary layers form, they form as horizontal layers.

If we find layers which are not horizontal,
They formed as horizontal layers first and got tilted

Answer 4

Steno’s Law of

ORIGINAL HORIZONTALITY

Question 5

Sedimentary layers of rock

Answer 5

Strata

Question 6

Study of what order layers go in

Answer 6

Stratigraphy

Question 7

Erosion surfaces between rocks showing that something has eroded away (part of rock record missing)

Answer 7

Unconformities

Question 8

Erosion between 2 PARALLEL layers of sedimentary rock

Answer 8

Disconformity

Question 9

Erosion between 2 sedimentary layers of rock that are NOT PARALLEL to each other

Answer 9

Angular unconformity

Question 10

Erosion between sedimentary layer of rock and either metamorphic or igneous rock

Answer 10

Non-conformity

Question 11

Pros - anyone can do it
- works on sedimentary rocks

Cons - will not tell you the age of rocks

Answer 11

Relative dating

Question 12

Pros: - gives age in years
- works on igneous rocks which make up most of the rocks in the earth

Cons: - need good samples to send to lab for analysis

       - expensive
       - takes time
       - doesn’t work on sedimentary rocks

Answer 12

Chronometric or absolute dating