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85 Cards in this Set
- Front
- Back
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What characteristics do geologist use to identify rocks?
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composition, color, and texture.
- all of them are used. One alone can't be used... (foe ex. color alone can't be used) |
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rock-forming minerals
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20 minerals that make up earths crust.
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granite
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a light-colored rock that has high silica.
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Basalt
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a dark colored rock that is low in silica.
-made up of many minerals |
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Texture
- how is it described? |
the look and feels of a rocks surface.
- described by its size, shape and patterns of the grains |
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grains
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particals that make up a rock.
- they give the rock texture |
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grain size
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-fine grain (grains harder to see)
-Coarse grain (grains easier to see) -No visible grain (used to describe a rock's texture) |
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Grain Shape
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-rounded grain
- jagged grain (used to describe a rock's texture) |
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Grain pattern
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-non banded
-banded (used to describe a rock's texture) |
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What are three main groups of rocks?
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-igneous
-sedimentary -metamorphic (this classifies the rocks according to how they are formed) |
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Igneous rock
2 types |
forms when magma or lava cools and hardens
1) extrusive - on the surface 2) intrusive - beneath the surface |
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Sedimentary rock
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froms when pieces of rock are presses and cemented together.
- can also have bones, leaves, shells and other materials - can happens when 2 continental plates collide and cause erosion |
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Metamorphic rock
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forms from other rocks that are changed by heat and pressure
-Usually UNDERGROUND - can form when there is a collision b/n 2 continental plates and one is forced down toward the hear |
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What characteristics are used to classify igneous rock?
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origin, texture, and mineral composition.
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How are igneous rocks used?
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used with tools and building materials
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Origin - Where do Igneous rock form?
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-Igneous rock may form on or beneath Earth's surface.
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Extrusive rock
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igneous rock formed from lava erupted onto earths surface.
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Intrusive rock
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igneous rock formed when magma hardens benath the earths surface.
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What does the Texture of igneous rocks depend on?
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-depends on size and shape of the mineral crystals.
- Also depends on the rate of cooling of the lava (Rapid cooling lava->fine smooth crystals - no visible grain) (slow cooling lava-> coarse grain with large crystals) |
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Fine grained rocks
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form rapidly cooling lava
-small crystals |
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Coarse graines rocks
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Slowly cooling magma
-large crystals |
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Silica
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a material found from oxygen and silicon.
-in many minerals. |
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How do sedimentary rocks form?
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-formed when sediment (shells, leaves, sand) is deposited by water and sand
-process of series -erosion -deposition -compaction -cementation |
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What are three major types of sedimentary rocks?
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clastic rocks, organic rocks, ad chemical rocks.
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How are sedimentary rocks used?
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building materialsand tools
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Sediment
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small, solid pieces of material that come from rocks or living things.
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Erosion
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in the proccess running water,wind, or ice loosen and carry away fragments of rock
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Deposition
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the process by which sediment settles out of water or wind carrying it.
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compaction
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the process that presses sediments together
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cementation
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the process in which dissolved minerals crystallize and glue particles of sediment together.
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clastic rocks
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a sedimentary rock that forms when rock fragments are squeezed together.
- made up of broken pieces of rocks |
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organic rocks
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forms where the remains of plants and animals are deposited in thick layers.
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chemical rock
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when minerals that are dissolved in a solution crystallize.
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how does coal form?
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when the remains of swamps plants are burried in water.
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what are two important organic rocks?
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limestone and coal
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what are some clastic rocks?
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shale, sandstone, conglomerate, and breccia.
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How do coral reefs form?
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when a coral animal dies it has a skeleton and then when many of them die there skeletons stack on top of each other to make a coral reef.
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WHat evidence do limestone deposits from coral reefs provide about Earths history?`
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limestone deposits began as coral reefs.
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coral reef
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a structure that if formed with skeletons.
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How coral animals live
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they are smaller then your finger nail and they catch microscropic animals that go by to eat
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Under what conditions do metamorphic rocks form?
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heat and pressure deep beneath the surface (in Earth's mantle) can change any rock into a metamorphic rock.
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How do geologists classify metamorphic rocks?
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to the arrangement of the grains that make up the rocks.
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A Rock
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A mixture of minerals, volcanic glass, organic matter, an other materials.
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Granite is a mixture of:
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Feldspar, quartz, mica, hornblende, and other minerals
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What are some rock forming minerals?
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Quartz, Feldspar, Mica, and Calcite
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Rock Cycle
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A model created by scientists to show how rocks change through time.
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What does the rock cycle do?
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It illustrates the processes that create and change rocks.
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What are the three types of rock?
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"Igneous
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Who discovered the rock cycle?
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James Hutton - Scottish physician & naturalist (1788)
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Igneous rocks
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Formed when hot magma cools and hardens.
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Lava
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Magma that has reached Earth's surface. Flows from volcanos.
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What is magma made of?
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Atoms and molecules of melted minerals.
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Intrusive igneous rocks
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Rocks that form by MAGMA below the Earths surface.
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Extrusive igneous rocks
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Rocks that form as LAVA cools above the Earths surface.
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Intrusive rocks - facts
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From magma - cool slowly - very large grains.
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Extrusive rocks - facts
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"From lava - cool rapidly
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Three types of volcanic glass.
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Pumice, obsidian, scoria.
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Volcanic glass properties
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"Made from lava
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Both intrusive and extrusive igneous rock can be also classsifed by:
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The type of magma that forms them.
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What are the 3 types of magma that form igneous rocks?
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"Basaltic
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Metamorphic rocks
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"Rocks that have been changed by temperature and pressure
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Metamorphic rocks is said to be foliated when:
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the mineral grains flatten and line up in parallel layers
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What is an example of foliated metamorphic rock?
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Slate
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Metamorphic rocks are said to be nonfoliated when:
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no layering occurs.
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What is an example of nonfoliated metamorphic rock?
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Marble
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What are the most common rocks on Earth?
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Igneous rocks
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Sedimentary rocks
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Form when sediments are pressed and cemented together.
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Weathering
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The process which breaks rocks down into smaller pieces.
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Erosion
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The movement of weathered material.
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Compaction
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One of the 2 processes which create sedimentary rock. Compaction works by pressure.
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Cementation
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One of the 2 processes which create sedimentary rock. Works by "gluing" the sediment together.
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Detrital sedimentary rock
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Rock created by cementation.
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Chemical sedimentary rocks
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Formed by minerals coming out of solution. (Like salt in the bottom of an empty glass.)
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Organic sedimentary rocks
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From fossils. (Dead organic things)
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List two common organic sedimentary rocks.
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"Chalk and coal
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List a common chemical sedimentary rock.
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Rock salt
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Why does magma tend to rise toward the Earth's surface?
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It is less dense than the surrounding rocks.
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During metamorphism of granite into gneiss, what happens to minerals?
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They align into layers.
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sandstone
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sedimentary
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limestone
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seimentary
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gneiss
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metamorphic
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obsidian
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Igeneous
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granite
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igneous
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slate
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metomorphic
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rock salt
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igneous
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