Lesson #6 (Early Earth and the Moon)
Worksheet #4 Relative Dating Activity Worksheet
Relative Time
By knowing the age of the rock that a fossil is found in, geologists can usually tell the age of the fossil. Sometimes they cannot give it an exact date, but they know that it is older or younger than another fossil. Dating a fossil by saying it is older or younger than another fossil is called relative dating. There are 3 laws that are used by scientists to systematically determine the relative age of a rock layer and the fossils found within it. They are the Law of Superposition, The Crosscutting Law, and Law of Inclusion The Law of Superposition “In any undisturbed sequence of rock layers, the oldest is at the bottom of the sequence, and the youngest layer is at the top of the sequence. The Cross­Cutting Law “Any feature that cuts across a layer of rock is younger than the rock it cuts across” (You can cut through something unless it exists first) The Law of Inclusions “If one layer of rock contains fragments of another rock, then it must be younger than the rocks it contains. 1 Lesson #6 (Early Earth and the Moon)
Worksheet #4 Use the Laws of Superposition, Inclusion and Crosscutting relationships to determine the relative ages of the following rock cross­sections. Determine the Oldest Rock first, and then work your way to the youngest. 1) Oldest____________________ _______________________________ Youngest_________________________ 2) Oldest____________________ ______________________________
_______________________________ _______________________________ Youngest_________________________ 3) Oldest____________________ ______________________________
_______________________________ _______________________________ Youngest_________________________ 2 Lesson #6 (Early Earth and the Moon)
Worksheet #4 4) Oldest Youngest 5) Oldest Youngest 6) Oldest Youngest 3 Lesson #6 (Early Earth and the Moon)
Worksheet #4 For the next 3 rock cross sections, You will lable the rock layers in relative order. Then you will be asked to compare 2 different rock layers. For each pair of letters, circle the older of the two, and then name which Law you used to identify the relative age. #7 Oldest Youngest A vs B _________________________ C vs D ________________________ D vs E _________________________ J vs K ________________________ #8 Oldest Youngest M vs A _________________________ J vs N _________________________ H vs C _________________________ D vs M ________________________ 4