Formation of Rocks (Copy)
1.1 Formation of Rocks – Cheat Sheet
| Rock Type | Formation | Characteristics | Examples |
|---|---|---|---|
| Igneous | Cooling & solidification of molten magma or lava | – Hard, crystalline- Non-porous- No layers | Granite (slow cooling, large crystals)Basalt (fast cooling, small crystals) |
| Sedimentary | Compaction & cementation of sediments (sand, mud, shells) | – Layered (strata)- Often contain fossils- Softer, more porous | Limestone (calcium carbonate, marine origin)Sandstone (compacted sand grains)Shale (compacted mud/clay, fine-grained) |
| Metamorphic | Alteration of existing rocks by heat & pressure | – Harder, more compact- Crystalline- May show foliation (banding) | Marble (from limestone)Slate (from shale) |
The Rock Cycle (Quick Summary)
- Magma → Igneous rock (cooling, solidification)
- Igneous rock → Sediments (weathering, erosion, deposition)
- Sediments → Sedimentary rock (compaction, cementation)
- Sedimentary/Igneous → Metamorphic rock (heat & pressure)
- Metamorphic → Magma (melting) → cycle repeats
Written and Compiled By Sir Hunain Zia, World Record Holder With 154 Total A Grades, 7 Distinctions and 11 World Records For Educate A Change O Level And IGCSE Environmental Management Full Scale Course