Geologic time

Which method for measuring the age of an object relies on radioactive isotopes present inside an object?

• rate of sedimentation

• law of superposition

• radioactive dating

• fossil comparison

Which method determines the relative age of Earth's sedimentary layers based on their position?

• rate of sedimentation

• law of superposition

• radioactive dating

• fossil comparison

Which of these choices is an example of the way a geologist would use relative dating?

• determining the minerals that make up rocks

• placing rock layers in order of oldest to youngest

• classifying rocks as igneous, sedimentary, or metamorphic

• using radioactive isotopes to determine the exact age of rock samples

Which of these choices is the best definition of absolute dating?

• determining the age of a rock layer by studying the fossils present

• finding the age of an object compared to other objects

• measuring the age of an object in years using any method

• determining the amount of a radioactive isotope in an object

What is the approximate age of Earth?

• 4.6 billion years

• 4.6 million years

• 46,000 years

• 4,6000 years

At one time, several kinds of camels lived in Florida. The evidence comes from fossils found in Florida. Which of these objects would be a fossil that shows that camels once lived in Florida?

• Sinkhole formed by a retreating glacier

• sedimentary rock that formed a long time ago

• crystal formation suspended from the ceiling of a cave

• remains of an organism preserved by geologic processes

Early in Earth's history, the atmosphere was mainly composed of ammonia, methane, nitrogen, carbon dioxide, and helium. Today, it is mostly composed of nitrogen and oxygen. What idea does this support about Earth?

• Earth has lost most of its atmospheric gases to radioactive decay

• Earth loses some of its atmospheric gases to space.

• Earth has always been able to support life.

• Earth is ever evolving and changing.

Limestone can be found at the top of the Himalayas, the highest mountain range in the world. Limestone is a rock that usually forms at the bottom of shallow, warm waters. What does this information show about Earth?

• It shows that Earth has evolved over time as areas of land that have once been covered in water, but no longer are.

• It shows that Earth has mostly convergent plate boundaries that push limestone from the ocean floor to the top of mountains.

• It shows that Earth circulates it minerals so often that limestone always ends up on the peaks of mountains.

• It shows that Earth has not changed much over the years as limestone has adapted to forming on mountain peaks