Rock Texture and Composition

The diagram show layers of sedimentary rocks and examples of their fossils. Which layer contains the youngest fossils?

• Layer 1

• Layer 2

• Layer 3

• Layer 4

Volcanic activity on Earth’s surface most likely results in the formation of which of the following types of rock?

• Mineral composition
• Extrusive igneous rock
• Clastic sedimentary rock
• Chemical sedimentary rock

Ricardo has an igneous rock in his rock collection. Where did this rock most likely form?

• in a volcano
• on a forest floor
•  on a coral reef
• at the bottom of a river

Metamorphic rock forms when

• magma cools and hardens.
• minerals crystallize out of sea water.
• heat and pressure change the composition and texture of a rock.
• natural cement binds rock fragments together.

In order to create a metamorphic rock, what must be present?

• magma
•  lava
• existing rock
• sediment

Most rocks are composed of

• minerals and organic matter
• cement and rock fragments
• sand and mud
•  man-made solids with crystals

When limestone is exposed to enough heat and pressure, it goes through physical changes. These changes can turn limestone into a different kind of rock called marble. Marble can be described as

• an igneous rock

• a synthetic rock

• a sedimentary rock

• a metamorphic rock

Which of the following set of characteristics best describes sedimentary rocks?

• crystal structure, definite chemical composition, inorganic, naturally occurring, solid

• glassy, lava flow, vesicular

• layers, fossils, rock pieces

• foliation, index minerals

What must happen to sediment in order for it to become a rock?

• weathering, erosion, and deposition
• compaction and cementation
• melting, cooling, and solidifying
•  heat and pressure

What kind of sedimentary rock is made of pieces of other rocks cemented together?

• organic
• stratified
• chemical
•  clastic