Topic 9 - Rocks, The Rock Cycle, and Geologic Time

Question 1

Summarize what these rock types are:

Igneous
Sedimentary
Metamorphic

Answer 1

->Igneous rocks are molten rocks that cool to become solid
-> Sedimentary rocks are formed by sedimentation of material at the Earth’s surface or within bodies of water
->Metamorphic rocks are from the transformation of a protolith (existing rock) because of a change in temp and pressure

Question 2

Define

Relative age dating

Answer 2

compare relationships to determine which rock is older and which rock is younger

Question 3

Define

Numerical Age Dating

Answer 3

measure radioactive decay to determine when mineral was formed

Question 4

Sed. Rocks

What is the PRINCIPLE OF SUPERPOSITION?

Answer 4

The youngest rocks are on top and the oldest rocks are at the bottom

Question 5

Sed. Rocks

What is the PRINCIPLE OF ORIGINAL HORIZONTALITY?

Answer 5

Sediment layers are originally deposited in a horizontal position

Question 6

Sed. Rocks

What is the PRINCIPLE OF LATERAL CONTINUITY?

Answer 6

Sediments are deposited over a large area in a continuous sheet

Question 7

Sed.Rocks

What is the PRINCIPLE OF CROSSCUTTING RELATIONSHIPS?

Answer 7

Geological features that cut across rocks must’ve formed after those rocks

Question 8

Sed. Rocks

What is the PRINCIPLE OF INCLUSIONS?

Answer 8

Rock mass adjacent to the one with inclusions had to be there first to provide the inclusions

Question 9

Sed.Rocks

What are UNCONFORMITIES?

Answer 9

Missing parts from rock records.

Question 10

What are FOSSILS? What do they do?

Answer 10

Remains or traces of prehistoric life preserved in sed. rocks.
Tell what environment they were in and time interval where they lived.

Question 11

What are BODY FOSSILS?

Answer 11

Preserved remains of body tissues

Question 12

What are TRACE FOSSILS?

Answer 12

Fossils that record the activities of past organisms

Question 13

What is the PRINCIPLE OF FOSSIL SUCCESSION?

Answer 13

Fossil organisms succeed one another in a definite and determinable order. Any time period can be recognized by its fossil content.

Question 14

What are INDEX FOSSILS?

Answer 14

Geographically wide-spread fossils that existed for a geologically short period of time

Question 15

How does RADIOMETRIC dating work?

Answer 15

Comparing the presence of a radioactive isotope within a sample to its known abundance on Earth and its known half life,