EXAM Surface of the earth Flashcards
Name the three types of rocks.
Igneous, sedimentary and metamorphic.
How does igneous rock form?
Magma that cools slowly underground.
Describe the 4 layers of the earth.
CRUST is mainly rock up to 40km and broken into plates.
MANTLE is solid and molten rock up to 2500km
OUTER CORE is liquid iron and nickel
INNER CORE is solid iron and nickel
Describe what topsoil is.
The layer of soil on the surface of the earth. It is often dark in colour and contains the decomposed remains of plants and animals. This makes it rich in nutrients.
What is subsoil?
The layer of soil that lies underneath the topsoil.
How does topsoil form?
Topsoil forms when rocks are broken down into tiny grains over time.
Describe the features of sandy soil.
Sandy soil contains more coarse sand grains and feels gritty between your fingers.
Describe the features of clayey soil.
Clayey soil contains more fine grains of clay and feels smooth between your fingers.
Describe the features of loamy soil.
Loamy soil is a mixture of clay and sand and contains humus. Plants grow best in loamy soil.
Why is it useful to have small animals like earthworms and termites move through the soil?
They open up spaces for air and water in the soil.
Where do nutrients come from in the soil.
Decomposed plants and animals.
What does it mean when soil is eroded?
This is when topsoil is washed away by water or blown away by wind.
Briefly explain what sedimentary rock is.
Sediment is deposited in layers and harden over many years.
Give the 5 main stages in the formation of sedimentary rock.
- Rocks break down into small grains.
- Mud and sand grains are moved by wind and water.
- Mud and sand are deposited in low-lying areas.
- New layers are deposited on top.
- The layers are compacted over time to form sedimentary rock.
Name 3 types of sedimentary rock.
Shale, limestone and sandstone.
