1. Use answer key to make correction to p. 2 in binder
DO NOW (Period 2 & 7 only)
Use answer key to make correction to p. 2 in binder
DO NOW QUESTION
What kind of unconformity is shown below? Explain.
Choices:
Disconformity
Nonconformity
Angular

2. Relative Dating: Which came first?
Chapter 6.2

3. What is relative dating?
Used to determine which events happened in Earth’s past
Used to determine if an object/event is older or younger than other objects/events

4. What is relative dating?

5. Put in order from oldest to youngest… A B C D
OLDEST C  A  B  D YOUNGEST

6. What is the principle of superposition?
Younger rocks lie above older rocks in undisturbed sequences
Sequence = order

7. In what order (sequence) was this cake was created?
Purple
(oldest – laid down first)
Blue
Green
Yellow
Orange
Red
(youngest – laid down last)

8. Grand Canyon – Arizona, USA

9. How do geologists Use the geologic column?
Undisturbed sequence of rock layers containing fossils and rock formations
Arranged from oldest to youngest
Geologists use to interpret information in rock sequences
Created by combining data from all known rock sequences in an area

11. How can a rock layer can be disturbed?
Fault
break in Earth’s crust where plates slide past one another
Intrusion
molten rock inside Earth pushes into rock and cools
Folding
rock layers bend and buckle from forces in Earth
Tilting
forces in Earth slant rock layers

12. FAULT
break in Earth’s crust where plates slide past one another

13. Intrusion
molten rock inside Earth pushes into rock and cools

14. Folding
rock layers bend and buckle from forces in Earth

15. Tilting
forces in Earth slant rock layers

16. What is an unconformity?
Surface that represents a missing part of the geologic column (missing rock layer)
Caused by nondeposition (sediment is no longer being despoited) or erosion (transport of sediment elsewhere)

17. How does a disconformity occur?
Rock layers are uplifted and eroded away
In the future, sediment is deposited on top of the old erosion surface
Most common type of unconformity
Part of a horizontal sedimentary rock sequence is missing

19. How does a nonconformity occur?
Intrusive igneous or metamorphic rock is uplifted and eroded away
In the future, sediment is deposited on top of this igneous or metamorphic rock
Horizontal sedimentary rock layers on top of eroded surface of older igneous or metamorphic rock

21. How does a angular nonconformity occur?
Forces in Earth tilt of fold layers of rock
Tilted or folded rock is uplifted and eroded away
In the future, horizontal layers of sediment is deposited
Occurs between horizontal layers of sedimentary rock and tilted or folded layers of sedimentary rock