5.1 Unconformities

What is the principle of superposition?

• The oldest rocks are on the top layer.

• The oldest rocks are on the bottom layer.

• Rocks are deposited in random order.

Tags

NGSS.MS-ESS1-4

Which principle states that rock layers are originally deposited horizontally?

• Lateral Continuity

• Original Horizontality

• Cross-Cutting Relationships

What is an unconformity?

• A type of fossil

• A gap in the rock record

• A rock layer that is older than another

Tags

NGSS.MS-ESS1-4

What do index fossils help geologists determine?

• The exact age of rocks

• The relative ages of rock layers

• The types of rocks present

Tags

NGSS.MS-ESS1-4

Why are hard parts of organisms more likely to become fossils?

• They decay faster.

• They do not decay easily.

• They are found in water.

What is an unconformity in geology?

• A continuous sequence of rock layers

• A gap in the geological record

• A type of fossil

• A mineral deposit

The diagram shows a geologic cross-section from a region.

What are the relative ages of the rocks from oldest to youngest ?

• W, V, X, Z, and Y

• W, Y, V, X, and Z

• W, V, X, Y, and Z

• W, V, Y, X, and Z

Tags

NGSS.MS-ESS1-4

The diagram shows three sedimentary rock layers and an igneous intrusion.

What is the relative age of igneous intrusion W?

• Igneous intrusion W is younger than sedimentary rock layers Z and X, but its relative age to layer Y cannot be determined.

• Igneous intrusion W is younger than sedimentary rock layers Y and Z but older than layer X.

• Igneous intrusion W is older than sedimentary rock layers Z and X, but its relative age to layer Y cannot be determined.

• Igneous intrusion W is older than sedimentary rock layers Y and X but younger than layer Z.

Tags

NGSS.MS-ESS1-4

What is the principle of cross-cutting relationships?

• Rocks are deposited in horizontal layers.

• Older rocks are cut by younger features.

• Fossils are found in specific rock layers.

Tags

NGSS.MS-ESS1-4

What does the principle of lateral continuity state?

• Older rock layers are always found above younger layers.

• Rock layers are deposited in vertical sequences.

• Rock layers extend horizontally in all directions until they thin out or encounter a barrier.