Chapter 14 Test

The crystals of a given mineral, given enough time and space to grow, develop a characteristic shape because

• of the temperature of the magma from which the mineral crystallized.
• each mineral has an orderly internal structure.
• of pressure from other minerals with higher crystallization temperatures that grow first.
• crystals are shaped so they will be worth a lot of money.

You observe a bedrock exposure next to a highway and identify it as a sedimentary rock called sandstone. At some point in this rock’s past, the following must have happened.

• A volcanic eruption must have occurred.
• Sediments must have once been buried beneath other rocks and sediments.
• The sandstone must have been subjected to enough heat and pressure to melt it.
• There must have been a desert that froze into sandstone.

A river carries sand and mud to its delta, where it is deposited. Over time, the sand and mud are buried deeply and cemented together. The sand and mud have become

• an extrusive igneous rock.
• an intrusive igneous rock.
• a sedimentary rock.
• a metamorphic rock.

The observed difference in density between continental crust and oceanic crust is most likely due to differences in their

• chemical composition.
• thickness.
• porosity.
• rate of cooling.

Which feature would be evidence that a rock formed directly from lava cooling quickly?

• large quartz, feldspar, and mica crystals
• fossils
• gas pockets
• cemented sand particles

Rocks are classified as igneous, sedimentary, or metamorphic based primarily on their

• texture.
• crystal or grain size.
• method of formation.
• mineral composition.

The internal atomic structure of a mineral most likely determines the mineral’s

• color, streak, and age.
• origin, exposure, and fracture.
• size, location, and luster.
• hardness, cleavage, and crystal shape.

Scientists use index fossils to determine the

• time period during which sedimentary rocks formed.
• chemical composition of rocks.
• temperature of igneous rocks.
• time period during which Earth’s atmosphere formed.

Uranium-235 decays into lead-207 and has a half-life of about 700 million years. This means that it takes ____ million years for half of an original sample of uranium-235 to turn into lead-207.

• 1/2
• 350
• 700
• 1,400

The major rock types are

• igneous, sedimentary, and metamorphic
• volcanic, sedimentary, and mineral
• continental, oceanic, and metamorphic
• big, medium, and small