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 Dating
a. ________________________________________________________
to the ages of other rock or events in the geological sequence
b. 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 -________________________________
_______________________________________________________.
Name: _________________________
b. The Law of Original Horizontality -___________________________
________________________________________________________
____________________________.
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
Name: _________________________
9. ______________________________________________________________
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 layers
a. Igneous Intrusion ________________________________________________________
________________________________________________________
12. Law of Cross Cutting Relations
Name: _________________________
13. Law of Cross Cutting Relations
a. Faulting is another example of cross cutting relation. The fault in younger
than all of the layers it cuts across
14. Law of inclusions
15.
a. The red line is _______________________________________________________
___________________________________________________________________
___________________________________________________________________
Name: _________________________
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.
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
Name: _________________________
b. Faulting – A fault is __________________________________________
___________________________________________________________
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 Columns
a. Geologists take core samples from the Earth’s Crust all over the world
b. 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