Igneous rocks like granite are often used for street paving and kerb stones in city centres because:
They are hard and do not wear away easily
What property of granite makes it a good material to use for gravestones?
It is hard and resistant to weathering
An igneous rock that is fine-grained or glassy must have:
Cooled rapidly after erupting from a volcano
When a rock is heated and re crystallised close to an igneous intrusion, the effect is called:
Contact metamorphism
The cliff face in a quarry is made up of layers of limestone at the top and sandstone at the bottom. Both the limestone and the sandstone are cut through by a basalt dyke (igneous intrusion). Which is the youngest rock (the most recently formed)?
Basalt
What property of basalt makes it a good material to use for road surfaces?
It is hard and resistant to weathering
Common on the surface of Mars, what is the name of the extrusive igneous rock formed from the rapid cooling of lava that is rich in magnesium and iron?
Basalt
Calcium carbonate, dissolved in
Sedimentary
Formation:
- Weathering and Erosion: Existing rocks are broken down into smaller pieces through weathering (physical and chemical breakdown) and erosion (transport of the weathered material)
- Transportation:
These sediments (fragments of rock, minerals, or organic matter) are carried away by wind, water, or ice to new locations. - Deposition:
Sediments accumulate in layers, often in bodies of water like lakes and oceans - Compaction and Cementation:
- Over time, the weight of overlying layers compacts the sediments, squeezing out water and air. Minerals precipitate from the water within the sediment and act as a “glue” to cement the particles together, forming solid rock
Types of Sedimentary Rocks:
- Clastic Sedimentary Rocks: These are formed from fragments of other rocks and minerals. Examples include:
- Sandstone: Made of sand-sized grains
- Shale: Made of fine-grained clay particles
- Conglomerate: Contains rounded pebbles and larger rock fragments
- Breccia: Similar to conglomerate, but with angular fragments
- Chemical Sedimentary Rocks: These form from minerals that precipitate out of solution (like saltwater)
- Examples include:
- Organic Sedimentary Rocks:These form from the accumulation of plant or animal remains
- Coal: Formed from the accumulation and compression of plant matter
- Fossiliferous Limestone: Limestone containing fossils
Key Characteristics:
- Layering (Bedding or Stratification): Sedimentary rocks are typically layered due to the way they are deposited
- Fossils:They often contain fossils of plants and animals that lived when the sediments were deposited
- Formation near the Earth’s surface:Unlike metamorphic and igneous rocks, they form at or near the Earth’s surface
- Varied Composition: Sedimentary rocks can be made of various materials, including mineral grains, rock fragments, and organic matter
Calcium carbonate, dissolved in water, may be deposited as limestone by:
Living Organisms
What type of soils would be treated with limestone to improve crop yields?
Acid soils
Many sedimentary rocks are good building stones because:
They can be cut and carved to make large blocks
Sediment deposits are most likely to become deeply buried and compacted if:
The area where they are deposited is slowly subsiding (sinking)
What do we call the material that holds the grains together in sedimentary rocks?
Cement
What happens to the porosity of sediments during compaction?
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