Why is this statement false: The caveman had dinosaur for breakfast.? Why is this statement false: The caveman had dinosaur for breakfast.? man and.

Why is this statement false: “The caveman had dinosaur for breakfast.”?

Why is this statement false: “The caveman had dinosaur for breakfast.”?

man and dinosaursnever lived at the same time

man and dinosaursnever lived at the same time

Laws of geologic historyLaws of geologic history

Superposition—Oldest rocks on the bottom of an undisturbed sequence of rockLaw of original horizontality—All rocks are initially deposited in flat (horizontal) rowsCross-cutting relationships—Objects which cross-cut rocks are younger than the rocks themselves (ex: fault or intrusion)

Superposition—Oldest rocks on the bottom of an undisturbed sequence of rockLaw of original horizontality—All rocks are initially deposited in flat (horizontal) rowsCross-cutting relationships—Objects which cross-cut rocks are younger than the rocks themselves (ex: fault or intrusion)

Using superposition, label the strata below

from oldest to youngest.

Using superposition, label the strata below

from oldest to youngest.

All rock layers are originally deposited in flat (horizontal) layers

Faults are always (older, younger)

than the rocks they cut through.

Faults are always (older, younger)

than the rocks they cut through.

Which is older:

F or S

How do you know?

These laws are based on the assumption that the forces at work today are the same

forces at work in history = uniformitarianism.uniformitarianism.

If a geologist finds an igneous sill, how can she

determine if the sill is an intrusion or an extrusion?

If a geologist finds an igneous sill, how can she

determine if the sill is an intrusion or an extrusion?

Is “H” an intrusion or extrusion?

How can you tell?

Is “H” an intrusion or extrusion?

How can you tell?

H is an intrusion.Contact

metamorphism on top

H is an intrusion.Contact

metamorphism on top

What is an unconformity? How does it complicate the relative dating of rock layers?

What is an unconformity? How does it complicate the relative dating of rock layers?

a buried erosional surface a buried erosional surface

a part of the rock record

is missing

a part of the rock record

is missing

Using the diagram to the left, identify where the unconformity is located by drawing an arrow and writing the word “unconformity” next to it.

What are

What characteristics must fossils have in order to be

good index fossils?

What characteristics must fossils have in order to be

good index fossils?

lived over a large geographic area (large horizontal distribution)

lived for a short period of time (small vertical distribution)

lived over a large geographic area (large horizontal distribution)

lived for a short period of time (small vertical distribution)

In the diagram below, a geologist has matched up

rock layers based on index fossils. In the diagram below, a geologist has matched up

rock layers based on index fossils. In geology, this is referred

to as CORRELATION In geology, this is referred

to as CORRELATION

Why are radioactive isotopes useful in determining the absolute age of a rock?

their half-lives are constanttheir half-lives are constant

What can be done to change the half-life of a radioactive isotope?

Why is this important?

NOTHING!it is reliable to calculate age

What radioactive isotope could be used to determine the absolute

age of material that was recently living?

carbon-14

What radioactive isotope could be used to determine the absolute

age of material that was recently living?

carbon-14

What is the half life of uranium-238?

4.5 x 109

4,500,000,000

4.5 billion years

choice (c)

If there is a 100g sample of C14, how many grams of C14 would remain after three half-lives?

How long would this take? Show all work.

100g 50g 25g 12.5g

3 half-lives x (5.7 x 103) =1.71 x 104 = 17,100 years