What is the rock cycle and how are rocks formed?

Contributed by:
kevin
The rock cycle is a concept used to explain how the three basic rock types are related and how Earth processes, over geologic time, change a rock from one type into another. Plate tectonic activity, along with weathering and erosional processes, is responsible for the continued recycling of rocks.
1.
2. The Life of a Rock
Layers of
sediment
join
together.
Igneous Sedimentary Rock
Changes are made
Melted rock cools from pressure and
and hardens
heat.
Metamorphic
3. Rocks become smaller, and smaller,
and smaller, and ...
smaller
• By erosion
• By wind
• By earthquake
• By floods
• By rain
• By slides
• By man
4. Terms to Know
• Weathering: the breaking up of
rocks and soil
• Erosion: the moving of weathered
rock and soil. Weathering allows
erosion to take place.
5. Products of Weathering
• Clay
• Sand
• Rock Fragments (pebbles and stones)
6. Rocks change…………..
• By earthquakes
• By volcanoes
• By heat and pressure
7. Sedimentary Rock is . . .
• Rock formed when
layers of small
particles of shell, rock,
and sand join
together.
8. Sedimentary Rocks
How They are Made
• Wind and water break down the earth
• Bits of earth settle in lakes and rivers
• Layers are formed and build up
• Pressure and time turn the layers to rock
9. Types of Sedimentary Rocks
Sandstone Limestone
Gypsum Conglomerate
Shale
10. Fossils
• Fossils are usually found in sedimentary
rock and are the remains or imprints of
plants and animals that died long ago.
11. Fossils-Life From the Past
• Fossils provide information about life and
conditions of the past.
• Scientific evidence shows that the Earth is
approximately 4.5 billion years old
12. Metamorphic Rock is . . .
• Rock that is formed
when pressure and
heat create changes
to sedimentary or
igneous rock.
13. Metamorphic Rocks
What are They?
• Rocks that have changed
• They were once igneous or sedimentary
• Pressure and heat changed the rocks
14. Types of Metamorphic Rocks
Schist Gneiss
15. Igneous Rock is . . .
• Rock that is formed
when melted rock
cools and hardens.
16. Igneous Rocks
What are They?
• Fire Rocks
• Formed underground by trapped,
cooled magma
• Formed above ground when volcanoes
erupt and magma cools
17. Types of Igneous Rocks
Granite Scoria
Pumice Obsidian
18. Review of the Rock Cycle
• How are sedimentary rocks formed?
• What is a fossil?
• How are metamorphic rocks formed?
• How are igneous rocks formed?
• Give an example of each type of rock.
• What is weathering?
• Explain what erosion is.
19. Credits
• These slides were a compilation of work
by:
• Jefferson County Schools Power Points
on Rocks
• http://jc-schools.net/PPTs-science.html
• Ellen Benegar (Suffolk Public Schools)