Name _______________________________________ Date _____________________ Period ___________
8.1 Determining relative Age
Definitions: Define the following terms IN COMPLETE SENTENCES.
1. uniformitarianism:
2. relative age:
3. law of superposition:
4. unconformity:
5. Law of crosscutting relationships:
Answer the following questions IN COMPLETE SENTENCES, where appropriate.
6. Who was James Hutton and for what is he most famous?
7. How have geologists refined Hutton’s ideas?
8. What evidence did Hutton propose to show that the Earth is very old?
9. What is strata and what might it show?
10. Name two types of rock that can form strata. Circle the one most commonly used for study.
11. Sedimentary rock layers are called ______________ and the boundary between two beds is called a
____________________________?
12. Determining the relative age of rock then, is based on the Law of _____________________________?
13. Using the Law of Superposition, one can assume the undeformed sedimentary rock layer is ____________
than the layers above it and __________________than the layers below it.
14. What can scientists assume about sedimentary rock layers that are not horizontal?
15. Tectonic forces may upset the original layers of sedimentary rock. Clues then are used to determine the
original position. _______________________ says that coarse and heavy layers should be found in the
bottom layers. The shape of a bedding plane, called a _______________________ occurs when sand
slides down the slope of a large sand dune. The tops of the layers ______________ before new layers are
deposited forming a curve at the bottom of the layer. _______________________________ are small
waves that form on the surface of sand due to action of water or wind. Crests of ripple marks point
____________________.
16. What does an unconformity show?
17. A _______________________ is an unconformity in which stratified rock rests upon unstratified rock. The
boundary between a set of tilited layers and a set of horizontal layers is an _____________________
conformity. A _______________________ results when the boundary between horizontal layers of old
sedimentary rock and younger, overlying layers that are deposited on an eroded surface.
18. How does the law of cross cutting relationships help scientists determine the relative ages of rock?