Name ____________________________________________________________________________ Date______________________

Geologic History

Fossils can only be found in ___________________________________________________ rocks.

Relative dating- Determining the age of rocks or events in ________________ to the age of other rocks and rock forming events.

Principle of Original Horizontality

o Rock form in _________________________ ___________________ parallel to earth’s surface

o These layers are known as ____________________________________

Deformed or distorted layers- rocks that are no longer in horizontal layerso _________________________ stratao _________________________ stratao _________________________ or uplifted strata

Principle of Superposition- o ____________________________________________________________

____________________o Rocks get _________________________ as you move up towards the

earth’s surface

Using the Principle of Superposition, label the strata from oldest to youngest

____________youngest

____________

____________

____________oldest

Law of Cross Cutting Relationshipso Rocks are

_____________________ than any _______________________________, ___________________________________ or other feature that cuts across them

o Faults are always (older, younger) than the rocks they cut through.

Igneous intrusions & extrusions- When ___________________ enters into pre-existing rock and crystallizesWhat happens when magma touches pre-existing rocks?________________________________

Which is older?F or S? __________________How do you know? ______________________ ___________________________________________________________________________________________________

Youngest___________

___________

___________

___________

___________

Oldest ___________

____________________________________________________________________________________________

Youngest ________

________

________

________

Oldest ________

______________________________________________________________

o If a geologist finds an igneous sill, how can he/she determine if the sill is an intrusion or an extrusion?

INTRUSIONS EXTRUSIONS

Is “H” an intrusion or an extrusion?

UNCONFORMITIES

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

layers?

What processes lead to an unconformity?

Find and outline the Unconformity

_______Youngest____________________________

Is “H” an intrusion or an extrusion?

On the diagram to the right, locate the unconformity by

drawing an arrow and writing the word

“unconformity” next to it.

X

_______Oldest

FOSSILSo What characteristics must fossils have in order to be good index fossils?

________________________________________________________________________________________________________________________________

_______________________________________________________________________________________________________________________________

o In geology this is referred to as

________________________________________________________

o Explain the theory of evolution ( in your own words)

o How does the fossil record support this theory?

Using page 8 &9 in the ESRT’s, answer the following questions

1) Approximately how many million years ago did the earliest amphibians appear?

2) Approximately how many million years ago was the initial opening of the Atlantic Ocean?

3) During which era did the earliest fish appear?

4) During which epoch did large carnivorous mammals appear?

5) Of the following rocks which would be most likely to contain fossils?a. rhyolite b. basalt c. metaconglomerate d. limestone

6) What is age of the bedrock at Binghamton, NY?

7) How does the age of the bedrock at Old Forge compare with that at Jamestown?

8) Name a location in NY State where you may be able to find bedrock which was formed at the peak of the eurypterid’s development.

9) Why would fossils be unlikely to be found in quartzite?

10) For each of the following locations in NY State below, identify whether fossils would be likely or unlikely:

Old Forge- Binghamton- Albany-

ABSOLUTE AGE- The __________________ age of a fossil or rock layero Why are radioactive isotopes useful in determining the absolute age of a

rock?

o What can be done to change the half-life of a radio-active isotope?

o What is a half-life?

o How long does it take to get to 0% of an isotope?

o Draw the generic graph of the half-life of a radio-active isotope

o What radioactive isotope could be used for determining the absolute age of a material that was recently living? _________________________________________________

o If the Half-life of Carbon 14 is 5.7 x 103, how much time has passed after 2 half-lives? _______________________________ After 3 Half-lives? ________________________________

o What is Potassium-40 used to date? ____________________________________________

How long in years is the half-life?_______________________________

How much time has passed after 2 half-lives? _______________________________

3 half-lives? ________________________________

o What is Uranium-238 used to date? __________________________________

o What is the half-life of U-238? (circle below)1.)4500 yrs 2.) 45,000 yrs 3). 4,500,000,000 yrs 4). 45,000,000,000 yrs.

How much time does it take U-238 to undergo 2 half-lives? _________________

Can we find a rock that has undergone 2 half-lives? Why or why not? __________________________________________________________________________________________________________________________________________________________________________________________________

o If there is a 100gram sample of C14, how many grams of the parent material would be left after 3 half-lives?_______________

o How many years would this take? (show your work below)