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ROCKS. What is a Rock?. rock - a naturally-occurring mixture of minerals, organic matter and other rocks. What is the difference between a rock and a mineral?. Rocks are made up of one or more minerals. Rock Classification. Rocks are classified by how they were formed. 3 types:
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What is a Rock? rock- a naturally-occurring mixture of minerals, organic matter and other rocks
What is the difference between a rock and a mineral? • Rocks are made up of one or more minerals.
Rock Classification • Rocks are classified by how they were formed. • 3 types: • Igneous- from magma or lava • Sedimentary- from sediment that has been cemented by minerals • Metamorphic- formed from intense heat and pressure
Distribution of Rocks on Earth Which rock type is most abundant (greatest amount) ?
Once a rock is formed, does it stay the same rock forever? • No! • Rocks are continually changed by many processes, such as weathering, erosion, compaction, cementation, melting, and cooling • Rocks can change to and from the three types (igneous, sedimentary, metamorphic)
What is the process through which rocks change? • The Rock Cycle—earth materials change back and forth among the different types of rocks
How are rocks redistributed? • The core, mantle, & crust are one giant rock recycling machine
Igneous Rocks • “Ignis” = Latin for “fire” • formed from the cooling of eithermagma or lava • the most abundanttype of rock • Classified according to their origin and composition
ORIGIN— Where rocks are formed • Below ground= from magma (intrusive igneous rock) • Usually have LARGE crystal grains (they cooled slowly) • Examples are: granite
more intrusive igneous rock • Some have large & small crystals • (called porphyritic)
Above ground = from lava (extrusive igneous rock) • Usually have SMALL or NO crystals (they cooled too quickly) obsidian ↑ ← basalt
more extrusive igneous rock • pumice → ←andesite
Practice Classifying Igneous Rocks as intrusive or extrusive
Basaltic Igneous Rocks —made from lava that is low in silica, rich in iron and magnesium. Rocks are dark-colored.
Granitic Igneous Rocks—made from magma high in silica and oxygen. Rocks are light-colored.
Andesitic Igneous Rocks—have a composition between basaltic and granitic.
Practice Classifying Igneous Rocks according to their composition:
Uses of Igneous Rock • Igneous rock is very hard so it is useful for tools and building materials. As we study uses of rocks, we are using the Human Ingenuity Lens.
Notes What is a rock? What is the difference between a rock and a mineral?
Notes 1. What are the 3 types of rocks? a) b) c)
2. How are rocks classified? 3. Which of the 3 types of rocks is most abundant? _______________
What is the rock cycle? Draw a diagram
4. The word igneous means5. Igneous rocks that form inside Earth from magma are called ___. 6. These rocks have ________ sized crystals.
7. Igneous rocks that form outside Earth from lava are called _________________. 8. These rocks have _____ sized crystals.
9. Give 3 examples of intrusive igneous rock.a)b)c)10. Give 3 examples of extrusive igneous rock.a)b)c)
In conclusion, view this video to review: • Rock_Formation.mov