Rocks Flashcards
What is geology?
The study of the Earth, the materials of which it is made. The structure of those materials and the processes acting upon them (How things have changed over time)
What is a rock?
A rock is a mixture of minerals. Minerals usually exist in rock as crystals of various kinds, shapes and sizes.
What is a mineral?
A mineral is a natural compound. It has a chemical name and a formula, like the compounds in science - but we use its geological name.
What are the most common atoms in rock?
Silicon and oxygen
What are some examples of rock in the world?
Soil, jewellery, tiles/worktops, mountains, bricks, milk, cereal or computers.
What are three ways to describe sedimentary rock?
Colourful, rough, has layers and reacts to erosion and weathering.
What are three ways to describe metamorphic rock?
Hardwearing, resistant to weathering and erosion and a ‘squished’ texture
What are three ways to describe igneous rock?
Shines when polished, resistant to erosion and hard.
How is sedimentary rock made?
It is formed by rocks and sea creatures over time. Rock particles are deposited in lakes and seas. They build up and compact the particles together. The particles travel by river/stream.
How is metamorphic rock made?
It is made when rocks are exposed to extreme pressure or heat.
How is igneous rock made?
It is made when magma cools and crystallises
What are some examples of sedimentary rock?
Limestone, sandstone and shale
What are some examples of metamorphic rock?
Marble and slate
What are some examples of igneous rock?
Granite, Pumice and basalt
What is the geological time scale?
The geological time scale is a record of the life forms and geological events in Earth’s history. Scientists developed the time scale by studying rock layers and fossils worldwide. Radioactive dating helped determine the divisions in the time scale.
During the carboniferous period in the UK, what were the weather conditions and what rocks were formed?
The weather was tropical, and coal and limestone were formed.
In which period did the Ice Age form?
The Ice Age formed in the Quaternary Period.
In which period was chalk formed?
Chalk was formed in the Cretaceous Period.
What are all the periods of the geological timescale? (Newest to oldest)
Neogene Paleogene Cretaceous Jurassic Triassic Permian Carboniferous Devonian Silurian Ordovician Cambrian Precambrian
What is an extrusive igneous rock?
A rock that is formed when magma cools and crystallises on the Earth’s surface. Pressure forces the magma out of the ground for a volcano, or it is slowly pushed upwards (called uplift) when it cools.
What is an intrusive igneous rock?
A rock that is formed when magma cools and crystallises below the surface (usually relatively deep into the Earth)
What can sedimentary rock turn into?
Metamorphic rock
What can metamorphic rock turn into?
Sedimentary rock and magma
What can magma turn into?
Igneous rock
What can igneous rock turn into?
Metamorphic rock and sedimentary rock
What is weathering?
Weathering is the breaking down of a rock by the action of things in its environment e.g. heat, cold, rain, plants, chemicals etc.
What is erosion?
Erosion is the wearing away and removal of rock, stone and soil by rivers, waves or glaciers.
What are the three types of weathering?
Physical, chemical weathering (acid rain) and biological.
How are fossils formed?
It’s the preserved remains of an animals. It’s rare for living things to become fossilised, as most just rot away. Under special conditions they form. The soft parts of the body decompose, leaving hard parts like the skeleton. This gets buried and more layers of sediment get built up on top.
What is the rock cycle showing?
The Earth’s rocks do not stay the same forever. They are continually changing, because of the processes such as weathering, erosion and large Earth movements. The rocks are gradually recycled over millions of years. This is called the Earth cycle.
What is physical weathering?
It is caused by the effects of changing temperatures on rocks, causing the rock to break apart. The process is sometimes assisted by water.
What are the types of physical weathering?
Freeze thaw and exfoliation
What is freeze thaw physical weathering?
It occurs when water continually seeps into cracks of rocks, freezes and expands, eventually breaking the rock apart.
What is exfoliation physical weathering?
It occurs as cracks develop parallel to the land surface - a consequence of the reduction in pressure during uplift and erosion. The breakdown of rocks by expansion and contraction as a result of daily temperature changes (onion skin weathering)
What are the types of chemical weathering?
Solution, Hydrolysis and Oxidation
What is solution chemical weathering?
The removal of rock in solution acidic rainwater. In particular limestone is weathered by rainwater containing dissolved CO2. This process is sometimes called carbonation.
What is hydrolysis chemical weathering?
The breakdown of frock by acidic water to produce clay and soluble salts.
What is oxidation chemical weathering?
The breakdown of rock by oxygen and water, often giving iron-rich rocks a rusty-coloured, weathered surface.
What is biological weathering?
Living organisms contribute to the weathering process in many ways.
Describe the first type of biological weathering (when trees…)
When trees put down their roots through joints or cracks in the rock in order to find moisture. As the tree grows, the roots gradually prise the rock apart.
Describe the second type of biological weathering (burrowing animals…)
Burrowing animals (moles, badgers and rabbits) can also make cracks bigger.
Describe the third type of biological weathering (lichens, algae…)
Lichens, algae and mosses can produce weak acids which open cracks in rock and exposes them to chemical and mechanical erosion.
Why does the UK have such a wide range of rocks?
The UK has a wide range of rock types formed in different environments. This is because the land has been on a long journey, and the events along the way explain our mountains. As it moved around, the land that is now the UK gathered sediment in many different environments over millions of years, so now the UK has a range of sedimentary rocks with different ages.
What are the main five different methods of forming rocks?
Compacting and cementing, heat and pressure, melting, weathering and erosion and cooling.
What is sand blasting?
The effect on rocks of being hit by small particles of sand carried by the wind.
What type of rock is found most commonly in England and Wales?
Sedimentary
In general, how do the ages of the rocks change as you go from the north to the south of Britain?
They get younger
What kinds of landscapes does mudstone form?
Low, flat land
What kind of soil does mudstone produce?
Thick soil
Where can mudstone be found??
Wales/England (down south)
What can mudstone be used for?
To create ceramic creations and to grow crops.
What happens to mudstone when it gets wet?
It forms clay.
What kind of soil does limestone produce?
The soil that limestone produces is thin and poor.
Where can limestone be found?
England
What can limestone be used for?
As the soil that limestone produces is thin and poor, it is used for sheep farming.
What structures does limestone naturally create?
Potholes and underground caves.
What landscapes does granite form?
Land that’s higher than the surrounding areas
What is granite’s soil like?
Thin and poor
What can granite be used for?
As granite’s soil is thin and poor and cannot be used for crops, it is used for sheep farming.
