Exploring the Rock Cycle

Which of the following is an example of an igneous rock?

• Limestone

• Granite

• Sandstone

• Shale

Answer explanation

Granite is an igneous rock formed from the cooling and solidification of magma. In contrast, limestone, sandstone, and shale are sedimentary rocks, which are formed from the accumulation of sediments.

What process forms sedimentary rocks?

• Melting

• Cooling

• Compaction and cementation

• Metamorphism

Answer explanation

Sedimentary rocks are formed through the processes of compaction and cementation, where sediments are pressed together and minerals precipitate, binding them into solid rock. This distinguishes them from igneous and metamorphic rocks.

Which stage of the rock cycle involves the transformation of rocks due to heat and pressure?

• Weathering

• Erosion

• Metamorphism

• Deposition

Answer explanation

The correct answer is Metamorphism, as this stage of the rock cycle involves the transformation of existing rocks into metamorphic rocks through the application of heat and pressure.

Identify the rock type that is formed from cooled magma or lava.

• Sedimentary

• Metamorphic

• Igneous

• Fossiliferous

Answer explanation

Igneous rocks are formed from the cooling and solidification of magma or lava. Sedimentary rocks form from sediment, and metamorphic rocks arise from existing rocks under heat and pressure. Fossiliferous is a type of sedimentary rock.

Which of the following best describes the formation of metamorphic rocks?

• Formed by the cooling of magma

• Formed by the accumulation of sediments

• Formed by heat and pressure altering existing rocks

• Formed by the evaporation of water

Answer explanation

Metamorphic rocks are formed when existing rocks undergo changes due to high heat and pressure, altering their mineral composition and structure. This distinguishes them from igneous and sedimentary rocks.

Explain why sedimentary rocks often contain fossils.

• They form from cooled lava.

• They form in layers where organisms can be trapped.

• They are formed under high pressure and temperature.

• They are formed from molten rock.

Answer explanation

Sedimentary rocks form in layers, allowing for the accumulation and preservation of organic materials. This process can trap organisms, leading to the formation of fossils, which is why they are commonly found in these rocks.

What is the main difference between intrusive and extrusive igneous rocks?

• Intrusive rocks form on the Earth's surface, extrusive rocks form below.

• Intrusive rocks form below the Earth's surface, extrusive rocks form on the surface.

• Intrusive rocks are sedimentary, extrusive rocks are metamorphic.

• Intrusive rocks are metamorphic, extrusive rocks are sedimentary.

Answer explanation

The main difference is that intrusive rocks form below the Earth's surface, allowing slow crystallization, while extrusive rocks form on the surface from lava that cools quickly.

Describe the process of weathering in the rock cycle.

• The breaking down of rocks into smaller pieces by natural forces.

• The melting of rocks into magma.

• The cooling and solidification of magma.

• The compaction of sediments into rock.

Answer explanation

Weathering is the process of breaking down rocks into smaller pieces through natural forces like wind, water, and temperature changes. This is essential in the rock cycle, as it prepares materials for erosion and sedimentation.

How does the rock cycle illustrate the concept of recycling in nature?

• Rocks are used once and then discarded.

• Rocks change from one type to another in a continuous cycle.

• Rocks are created and destroyed without any change.

• Rocks remain the same throughout time.

Answer explanation

The rock cycle demonstrates recycling in nature as rocks continuously change from one type to another—igneous, sedimentary, and metamorphic—through processes like melting, erosion, and pressure, illustrating a natural cycle of transformation.

Differentiate between clastic and chemical sedimentary rocks.

• Clastic rocks form from organic material, chemical rocks form from minerals.

• Clastic rocks form from fragments of other rocks, chemical rocks form from mineral precipitation.

• Clastic rocks form from cooled magma, chemical rocks form from heat and pressure.

• Clastic rocks form from heat and pressure, chemical rocks form from cooled magma.

Answer explanation

Clastic sedimentary rocks are formed from the accumulation of fragments of other rocks, while chemical sedimentary rocks result from the precipitation of minerals from solution. This distinction highlights the processes involved in their formation.