Chapter 2 Rocks: Minerals & Mixtures
Guided Notes
Name: ________________________________ Date:___________ Class: STEM Gr. 6 Hour:_______
Section 1: The Rock Cycle
Objectives
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Describe two ways rocks have been used by humans.
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Describe four processes that shape Earth’s features.
•
Describe how each type of rock changes into another type as it moves through the rock
cycle.
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List two characteristics of rock that are used to help classify it.
The Value of Rock
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What Is Rock? Scientists define rock as a naturally occurring solid mixture of crystals of
one or more minerals.
Why Is Rock Important? Rock has been an important natural resource for as long as
humans have existed. Early humans used rock to make tools. Ancient and modern
civilizations have used rock as a construction material.
Processes That Shape the Earth
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Weathering, Erosion, and Deposition Weathering, erosion, and deposition are all
processes that shape the surface of the Earth.
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Heat and Pressure Sedimentary rock can form when buried sediment is squeezed by
the weight of overlying layers of sediment. If the temperature and pressure are high
enough, the rock can change into metamorphic rock.
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How the Cycle Continues Buried rock is exposed at the Earth’s surface by a
combination of uplift and erosion. This continues the rock cycle.
Illustrating the Rock Cycle
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The Flow of Rock The rock cycle is the continual process by which new rock forms from
old rock material.
Round and Round It Goes
Chapter 2 Rocks: Minerals & Mixtures
Guided Notes
•
Rolling Stones The sequence of events in the rock cycle depends on processes, such as
weathering, erosion, deposition, pressure, and heat, that change the rock material. Look
at the illustrated rock cycle on the next slide and identify what processes are taking
place at each stage.
Rock Classification
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Composition The composition of a rock is determined by the minerals that make up the
rock.
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Texture The texture of a rock is determined by the size, shape, and positions of the
grains that make up the rock.
Chapter 2 Rocks: Minerals & Mixtures
Guided Notes
Name: ________________________________ Date:___________ Class: STEM Gr. 6 Hour:_______
Section 2: Igneous Rock
Bellringer
Do you think rocks that cooled and solidified from lava on Earth’s surface would look different
from those that cooled and solidified from magma inside the Earth? Would you be more likely
to find igneous rock in the Rocky Mountains or in the Hawaiian Islands?
Explain your answer in your science journal.
Objectives
•
Describe three ways that igneous rock forms.
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Explain how the cooling rate of magma affects the texture of igneous rock.
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Distinguish between igneous rock that cools within Earth’s crust and igneous rock that
cools at Earth’s surface.
Origins of Igneous Rock
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Formation Igneous rock forms when magma cools and hardens.
Composition and Texture of Igneous Rock
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Appearance Determined by Cooling Rate Igneous rocks can be composed of a wide
variety of minerals. The texture of igneous rock is determined by the rate at which the
rock cools.
Igneous Rock Formations
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Intrusive Igneous Rock When magma intrudes, or pushes, into surrounding rock below
the Earth’s surface and cools, the rock that forms is called intrusive igneous rock.
Intrusive igneous rock usually has a coarse-grained texture because it is well insulated
by surrounding rock and cools very slowly. Some intrusive igneous formations are
illustrated on the next slide.
•
Extrusive Igneous Rock Igneous rock that forms from magma that erupts, or extrudes,
onto the Earth’s surface is called extrusive igneous rock. Extrusive rock is common
around volcanoes.
Chapter 2 Rocks: Minerals & Mixtures
Guided Notes
Chapter 2 Rocks: Minerals & Mixtures
Guided Notes
Name: ________________________________ Date:___________ Class: STEM Gr. 6 Hour:_______
Section 3: Sedimentary Rock
Bellringer
Tree rings are formed each year of a trees life cycle. Tree rings exist because the weather
changes of the seasons are reflected in the trees bark as the tree grows. Sedimentary rock is
formed in layers over time much the same way. Events like forest fires and droughts will be
visible in tree rings just as they are visible in sedimentary rock layers. How are layers in
sedimentary rock alike or different from rings in a tree? What can geologists infer from
examining sedimentary rock layers?
Record your answers in your science journal.
Objectives
•
Describe the origin of sedimentary rock.
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Describe the three main categories of sedimentary rock.
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Describe three types of sedimentary structures.
Origins of Sedimentary Rock
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How Sedimentary Rock Is Formed Through the process of erosion, rock and mineral
fragments, called sediment, are moved from one place to another. Eventually, the
sediment is deposited in layers. The layers develop into a natural cement that binds the
rock and mineral fragments together into sedimentary rock.
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Where Sedimentary Rock Is Formed Sedimentary rock forms at or near the Earth’s
surface.
Composition of Sedimentary Rock
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Clastic Sedimentary Rock Clastic sedimentary rock forms when rock or mineral
fragments are cemented together.
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Chemical Sedimentary Rock Chemical sedimentary rock forms from solutions of
dissolved minerals and water.
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Organic Sedimentary Rock Organic limestone forms from the remains of plants and
animals.
Sedimentary Rock Structures
Chapter 2 Rocks: Minerals & Mixtures
Guided Notes
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Common Structures Sedimentary structures include ripple marks, mud cracks, and raindrop impressions.
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Stratification The most important feature of sedimentary rock is stratification.
Stratification is the process in which sedimentary rocks are arranged in layers.
Chapter 2 Rocks: Minerals & Mixtures
Guided Notes
Name: ________________________________ Date:___________ Class: STEM Gr. 6 Hour:_______
Section 4: Metamorphic Rock
Bellringer
Write a brief description of how cookies are made. How is the mixture of raw ingredients
like sedimentary rock? Do the raw ingredients of a cookie look the same after they are
done baking? Describe how cookie dough metamorphoses when it is baked in an oven.
Record your responses in your science journal.
Objectives
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Describe two ways a rock can undergo metamorphism.
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Explain how the mineral composition of rocks changes as the rocks undergo
metamorphism.
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Describe the difference between foliated and nonfoliated metamorphic rock.
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Explain how metamorphic rock structures are related to deformation.
Origins of Metamorphic Rock
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Contact Metamorphism One way rock can undergo metamorphism is by being heated
by nearby magma. When magma moves through the crust, the magma heats the
surrounding rock and changes it, causing contact metamorphism.
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Regional Metamorphism When pressure builds up in rock that is buried deep below
other rock formations or when large pieces of the Earth’s crust collide with each other,
regional metamorphism occurs.
Chapter 2 Rocks: Minerals & Mixtures
Guided Notes
Composition of Metamorphic Rock
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Changes in Composition As rocks undergo metamorphism, the original minerals in a
rock change into new minerals that are more stable in new pressure and temperature
conditions.
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Index Minerals Many of these new minerals form only in metamorphic rock. These
minerals are known as index minerals, and are used to estimate the temperature, depth,
and pressure at which a rock undergoes metamorphism.
Textures of Metamorphic Rock
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Foliated Metamorphic Rock Foliated metamorphic rock has mineral crystals aligned in
planes or bands.
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Nonfoliated Metamorphic Rock Nonfoliated rocks have unaligned mineral crystals.
Metamorphic Rock Structures
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Deformation Metamorphic rock structures are caused by deformation.
Concept Map
Use the following terms to complete the concept map: clastic, exclusive, igneous,
intrusive, metamorphic, regional, rocks, sedimentary.
Chapter 2 Rocks: Minerals & Mixtures
Guided Notes
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