The rock cycle shows how rocks are constantly being created, destroyed, and transformed. It takes millions of years, but rocks change from one type to another in a never-ending cycle!
πΏ Three Types of Rocks
π
Igneous Rocks
Formed from: Cooled magma or lava
Features: Crystals form as rock cools
Examples: Granite, basalt, obsidian, pumice
"Igneous" = fire (Latin)
ποΈ
Sedimentary Rocks
Formed from: Layers of sediments cemented together
Features: Often has layers, may contain fossils
Examples: Sandstone, limestone, mudstone, coal
"Sediment" = settling material
π How the Cycle Works
π IGNEOUS
β weathering & erosion β
ποΈ SEDIMENTARY
β heat & pressure β
π METAMORPHIC
β melting β
π₯ MAGMA β back to igneous!
Key Processes
- Weathering β breaking down rocks (wind, water, ice)
- Erosion β moving rock pieces to new places
- Deposition β sediments settle in layers
- Compaction/Cementation β layers pressed together
- Heat & Pressure β changes rock structure
- Melting β rock becomes magma
- Cooling β magma becomes solid rock
π³πΏ Rocks of Aotearoa
Special NZ Rocks
- π Pounamu (greenstone) β metamorphic, taonga, found in Te Wai Pounamu
- π Basalt β igneous, from Auckland volcanoes
- ποΈ Greywacke β sedimentary, forms much of our mountains
βοΈ Activities
Activity: Draw the Rock Cycle
Create a diagram showing how rocks change from one type to another. Include arrows and labels for each process.
Draw your rock cycle diagram here
π©βπ« Teacher Notes
Curriculum Links
- Science: Planet Earth β geological processes
- Te Ao MΔori: Significance of pounamu