Law of Superposition and Index Fossils

Earth History

Earth Scientists​

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Geologist – a scientist who studies the Earth’s crust as well as the processes and history that shaped it

Paleontologist – a scientist that studies fossil remains found on the Earth’s surface in order to study primitive life forms such as: plants, animals, fungi, and bacteria

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Poll

Would you be intested in being a paleontologist or a geologist?

• Yes!!!!

• Probably not

​Group Time!

1) What do you know about fossils?

2) Have you ever seen a movie or television show that shows fossils?​

3) Why do scientists study fossils? ​

Directions: Discuss the following questions in your group!

​Stratigraphy

• A branch of geology dealing with the arrangement of sedimentary rock layers or strata

• Geologists assume the newest rock layers are on top of the older ones, unless some type of disturbance occurs. 

Called the Law of Superposition

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​Sedimentary Rock Layers

Multiple Choice

What law states that the newest rock layers are at the top?

• Law of conservation of mass

• Law of Superposition

• Natural Selection

Draw

Circle the letter that represents the youngest rock layer.

Draw

Shade in the area with the oldest rock layer.

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Relative Age

• The strata of sedimentary rocks is important in determining their relative age.

• Relative age determines the “relative” order of past events but not the absolute age.

• Like saying you’re relatively younger than your grandfather.

​Relative Age

• Strata is sometimes disturbed.

• Here we see a fault (E) and an igneous intrusion (D)

• See if you can determine the order of the strata in this diagram. 

• Determining relative age in the field is sometimes very difficult because of these disturbances.

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Open Ended

Type in the order of rock layers from oldest to youngest.

Open Ended

Type in the order of rock layers from oldest to youngest.

Open Ended

What are two things you learned from the video?