Earth History Review - BM 2

Which statement best describes the Law of Superposition?

• Each sedimentary layer of rock represents 1,000 years of Earth’s age, much like the rings of a tree.
• In undisturbed layers of sedimentary rock, the upper rock layers are older than the lower rock layers.
• In undisturbed layers of sedimentary rock, the lowest layers contain the older rocks.
• Rocks that form near volcanoes are older than surrounding rock.

A scientist finds the bones of a dinosaur. What could help the scientist determine the approximate age of the dinosaur bones?

• the birds living in the area of the bones
• the weather conditions in the area of the bones
• the kinds of trees living in the area of the bones
• the index fossils in the area of the bones

Which layer in this diagram is the youngest?

• E
• A
• B
• D

Which layer in this diagram is the oldest?

• E
• A
• B
• D

Which is a process that allows scientists to compare rock layers with others in a sequence to determine their age?

• radiometric dating
• absolute dating
• relative dating

If a metamorphic rock contains an intrusion of igneous rock, which rock is the oldest?

• The igneous rock is older.
• The rocks are the same age.
• The metamorphic rock is older.

What can be used to find the exact age of a rock specimen?

• ice cores
• index fossils
• radioactive dating

Radioactive dating is used to study which element in igneous and metamorphic rocks?

• carbon
• krypton
• uranium

Several different fossils were found in rock layers in a geologic column. Above these rock layers, the fossils were almost nonexistent. Which most likely explains these observations?

• A nonconformity occurred.
• All the organisms migrated.
• A period of mass extinction occurred.

Which best describes how ice cores are important to the study of geologic history?

• They show unconformities, which signal changes in deposition.
• They hold index fossils, which are used to date the different ice cores.
• They contain evidence showing changes in the atmospheric composition over time.
• They follow the Law of Superposition, which gives reasons for extinctions of species.