Chapter 4

The Earth's geological history is divided into how many eons?

4

You find a fossil, and through careful study you find that only one-sixteenth of the carbon-14 that it once contained is still remaining in it. Carbon-14 has a half-life of approximately 5700 years. You can conclude that the age of the fossil is about __________.

5700 yr = 22,800 years

According to current understanding, outgassing released water and other gases from Earth's interior. How did these gases get trapped in the interior in the first place?

As Earth accreted, planetesimals from colder regions of the solar system brought ices that became trapped gas in the interior.

Without the greenhouse effect, __________.

Earth would be too cold for liquid water

The fact that Earth's interior has denser metals in the core and lower-density rock nearer to the surface tells us that ________.

Earth's interior was once hot enough to have melted

Why are there so many fewer large impact craters on the seafloor than on continents?

Most seafloor craters have been covered up by new crust.

You study two regions of the Moon. Region 1 is densely cratered. Region 2 is mostly smooth, with just a few craters. What can you conclude?

Region 1 is an older portion of the surface than Region 2.

Which of the following is a key piece of evidence favoring the giant impact model for the Moon's formation over other proposed models?

The Moon lacks easily vaporized materials that are common on Earth.

Which of the following is required for plate tectonics to occur on a world?

The world must have a relatively thin and brittle lithosphere.

When heat and pressure are applied to a sedimentary rock it turns into

a metamorphic rock

Differentiation is a process by which

denser materials like iron sank to the center of the Earth while less dense materials like rock rose to the surface

Smaller worlds are more prone to atmospheric loss via impacts than large worlds because they

have weaker gravities

Rocks are found on the surface of another planet which appear to have been formed from the solidification of molten lava. Given this, they are most likely to be classified as

igneous

Basalt is a common type of

igneous rock

Geological processes on the Earth's surface are directly related to

internal heat

What is the most important role that the carbon dioxide cycle plays in the regulation of the Earth's climate?

it regulates the surface temperature by varying the amount of carbon dioxide in the atmosphere

The leading hypothesis for Venus's lack of a global magnetic field is its ________.

slow rotation

How are the "geological record" and the "fossil record" related?

the fossil record is part of the geological record

Without plate tectonics, Earth's climate would not be so stable because ________.

there could be no carbon dioxide cycle

Chemical analysis of a rock can tell us

what the rock is made of