Name: _________________________

Geologic Principles and Relative Dating

1. How old is the Earth?a. ________________________________________________________b. Much of its history is recorded in the rock.c. Observations of fossils, rock types, evidence of faulting, uplifts and

folding as well as __________________________________________________________________________________________________

2. Relative Datinga. ________________________________________________________

to the ages of other rock or events in the geological sequenceb. Saying “ ________________________________________________”

shows its age relative to a known.c. This means that geologists can say which layers are older than which

and thus ________________________________________________3. Principle of Uniformitarianism

a. This geologic Principle states that all geological processes ( _______________________________________________________________) that occur today also occurred in the past in the same way.

b. ________________________________________________________4. Time is the rate at which things change. The history of the Earth is explained

as on order of events. There are 2 ways of dating these events in geology.a. The first manner of depicting the order of geologic events is called

_______________________________. In this technique events are simply younger or older than some other event. _____________________________________________________________. For example:

The rocks in Bryce Canyon were deposited before the canyon formed.

5. The basic Principles are:a. The Law of Superposition -________________________________

_______________________________________________________. b. The Law of Original Horizontality -___________________________

____________________________________________________________________________________.

Name: _________________________

c. The Law of Cross Cutting Relationships -___________________________________________________________________________.

d. The Law of Inclusions -__________________________________________________________________________________________.

e. These are the fundamental principles geologists use in determining the sequence of events and relative ages of layers that are found in the rock record. Following are examples of each.

6. Law of Superposition

7. __________________________________________________________________________________________________________________________

8. Law of Original Horizontality

9. ______________________________________________________________

Name: _________________________

10. Law of Cross Butting Relations

a. This red area represents an igneous intrusion. It is younger than the sedimentary rock that it cuts across

11. Features within the rock layersa. Igneous Intrusion -

________________________________________________________________________________________________________________

12. Law of Cross Cutting Relations

13. Law of Cross Cutting Relationsa. Faulting is another example of cross cutting relation. The fault in younger

than all of the layers it cuts across

Name: _________________________

14. Law of inclusions

15.

a. The red line is _____________________________________________________________________________________________________________________________________________________________________________________________

16. There are 3 main types of Unconformities:a. Disconformity – The layers above and below the erosional surface are parallel.

They could be horizontal or tilted.

Name: _________________________

b. Angular Unconformity – tilted rocks are eroded and a new set of sediment are laid down on top of them.

c. Nonconformities – Sediment layers set on top of and around an intrusion of igneous rock that has been eroded.

17. Disturbed Rock Layers a. Folding – Occurs when ________________________________________

___________________________________________________________i. Often causes Mountains

b. Faulting – A fault is _____________________________________________________________________________________________________

Name: _________________________

c. Tilting – Occurs when ____________________________________________________________________________________________________

18. Index Fossils – Used to determine the age of the rock the fossil is found in if the fossil meets the two conditions

a. __________________________________________________________b. __________________________________________________________

19. Geologic Columnsa. Geologists take core samples from the Earth’s Crust all over the worldb. They take __________________________________________________

__________________________________________________________c. They match up layers based on _________________________________

___________________________________________________________d. Sometimes layers are missing from one column because of an

unconformity, so geologists __________________________________________________________________________________________________________________________________________________________

20. Core Samples

21. Core Samples Put together