CB- Rocks. Chpt 5. 6th grade Earth Science

Question 0

What are the three major groups of rocks?

Answer 0

Metamorphic, igneous and sedimentary

Question 1

What characteristics are used to identify rocks?

Answer 1

Color, texture and mineral composition

Question 2

What terms describe the texture of a rock?

Answer 2

Grain size
Grain shape
Grain pattern
No visible grain - glassy appearance

Question 3

Describe grain sizes and give examples

Answer 3

Coarse grained - Diorite

Fine grained - need microscope to see. Slate

Question 4

Describe different grain shapes

Answer 4

• tiny sand like particles
• small seeds
• crystal shapes. - Granite
• smooth and rounded fragments- conglomerate
• jagged fragments

Question 5

Describe grain patterns.

Answer 5

Flat layers
Wavy, swirling patterns
Rows of multicolored
Random grains.

Question 6

How is mineral composition determined?

Answer 6

Cutting rock into thin slivers and exami inv under a microscope. Can also do testing with acid and magnets.

Question 7

How are metamorphic rocks formed?

Answer 7

Heat, pressure or chemical reactions change existing rock. Mostly deep underground

Question 8

How is igneous rock formed?

Answer 8

From cooling of molten rock
Magma- below surface
Lava- above ground.

Question 9

How is sedimentary rock formed?

Answer 9

Rock particles and remains of plants/animals are pr

Question 10

What is a rock’s texture?

Answer 10

Look and feel of he rock surface. T

Question 11

What characteristics re used to classify igneous rocks

Answer 11

Origin
Texture
Mineral composition

Question 12

Describe the origins of igneous rocks

Answer 12

Extrusive - formed from erupting lava.
ex- Basalt which forms most of crust
Intrusive - magma hardens below ground. Ex- Granite

Question 13

Describe the textures seen in igneous rocks

Answer 13

Fine grained - rapid cooling of lava
Coarse grained - slow cooling magma. Large crystals
Porphyritic - large crystals scattered in fine grained rock.

Question 14

Describe the mineral composition of igneous rocks

Answer 14

Lava - Less silica- dark colored rock- Basalt

Magma - high silica - light colored - Granite

Question 15

Why are some igneous rocks dark and others light?

Answer 15

Depends on silica content
Lava - Less silica- dark colored rock- Basalt
Magma - high silica - light colored - Granite

Question 16

Explain what causes an igneous rock to have fine grained or coarse grained texture

Answer 16

Depends on cooling time.
Fine grained - rapid cooling of lava
Coarse grained - slow cooling magma. Large crystals
Porphyritic - large crystals scattered in fine grained rock.

Question 17

What is the difference between intrusive and extrusive rocks? Give examples of each

Answer 17

Extrusive - formed from erupting lava.
ex- Basalt which forms most of crust
Intrusive - magma hardens below ground. Ex- Granite

Question 18

Describe uses of igneous rocks

Answer 18

Tools, building materials, and decorations.

Granite counters and floors
Basalt - gravel
Pumice - cleaning and polishing
Perlite - planting

Question 19

How do sedimentary rocks form?

Answer 19

Erosion- by wind or water
Deposits
Compaction
Cementation

Question 20

What are the three major types of sedimentary rock?

Answer 20

Clastic. - shale, sandstone, conglomerate
Organic - coal, limestone
Chemical - gypsum

Question 21

Describe two ways limestone can form?

Answer 21

Chemically - calcite comes out of solution

Organically - shells dissolve

Question 22

Describe a common type of limestone

Answer 22

Chalk.

Question 23

Describe erosion

Answer 23

Water or wind carry away rock fragments

Question 24

Describe deposition

Answer 24

Sediment settles out of water or wind carrying it. Can include remains of living things also.

Question 25

Describe compaction

Answer 25

Process that presses layers of sediments together. Due to weight of layers above.

Question 26

What is sediment?

Answer 26

Small solid pieces of rocks or living things.

Question 27

Define cementation

Answer 27

Minerals dissolve in rock sediment and crystallize to glue sediment particles together

Question 28

Give examples of clastic rock.

Answer 28

Shale- formed from clay particles Sandstone - formed from sand Conglomerate - various size fragments. Rounded edges Breccia - various size fragments. Sharp edges.

Question 29

Describe two common organic rocks

Answer 29

Coal - made from swamp plants | Limestone - made from shells. Chalk is one type

Question 30

Describe some uses of sedimentary rock

Answer 30

Building materials, making cement, chalk for writing.

Question 31

How do metamorphic rocks form?

Answer 31

Heat and pressure beneath earth's surface change the rocks characteristics. Collisions between tectonic plates push rock down towards the heat of the mantle.

Question 32

How do geologists classify metamorphic rocks?

Answer 32

By the arrangement of the grains that make up the rocks. Foliated - parallel bands or layers. Ex - slate Randomly - marble

Question 33

What characteristics are used to classify metamorphic rocks?

Answer 33

By the arrangement of he grains making up the rocks.

Question 34

Which properties of a rock may change as the rock becomes metamorphic?

Answer 34

- Size and shape of the grains or mineral crystals | - pressure squeezes grains into flat parallel layers

Question 35

Describe uses of metamorphic rock

Answer 35

Building materials, sculptures - marbles | Flooring, roofing, walkways - slate