rock cycle

What are the three main rock types?

Igneous, sedimentary, and metamorphic.

What is an example of each rock type?

Igneous: Granite (plutonic) or Basalt (volcanic)

Sedimentary: Limestone or Sandstone

Metamorphic: Marble (from limestone) or Quartzite (from sandstone)

What is the difference between intrusive (plutonic) and extrusive (volcanic) igneous rocks?

Intrusive (plutonic): Formed inside Earth's crust, cools slowly, large crystals (e.g., Granite)

Extrusive (volcanic): Formed on Earth's surface, cools quickly, small crystals (e.g., Basalt)

What are the stages of the rock cycle?

1. Magma cools to form igneous rock

2. Weathering and erosion break rocks into sediments

3. Sediments compact into sedimentary rock

4. Heat and pressure turn sedimentary/igneous rocks into metamorphic rock

5. Metamorphic rock can melt into magma, restarting the cycle

What factors cause metamorphism in rocks?

Heat, pressure, and chemical changes.

What is lithification?

The process of compacting and cementing sediments into solid rock.

How does sedimentary rock become metamorphic rock?

Through heat and pressure (e.g., Limestone → Marble, Sandstone → Quartzite).

What is the source material for each rock type?

Igneous: Magma/lava

Sedimentary: Sediments from weathered rock, plants, or animals

Metamorphic: Existing rocks altered by heat/pressure

What is silica depth, and why is it important?

Silica depth refers to the amount of silica in magma. It affects the viscosity of lava and the type of igneous rock formed.

What is the difference between thermal and regional metamorphism?

Thermal metamorphism: Heat from magma changes rock composition

Regional metamorphism: Heat and pressure over a large area, often in mountain building

What is the difference between weathering and erosion?

Weathering: Breakdown of rocks in place

Erosion: Movement of weathered materials by wind, water, or ice

What is the difference between intrusive and extrusive igneous rocks?

Intrusive: Forms inside the Earth, cools slowly, large crystals

Extrusive: Forms on the surface, cools quickly, small crystals

Where are igneous, sedimentary, and metamorphic rocks commonly found?

Igneous: Found in volcanic regions (e.g., Iceland, The Giant’s Causeway in Ireland)

Sedimentary: Common in low-lying areas, riverbeds, and ocean floors (e.g., Limestone in the Burren, Ireland)

Metamorphic: Found in mountain ranges where heat and pressure occur (e.g., Quartzite in the Wicklow Mountains)

At what depth do plutonic (intrusive) rocks form?

Plutonic rocks form deep within the Earth’s crust, typically at depths of 5 km or more.