1. The contribution of minerals to rock composition. 2. Classify rocks by their process of formation. 3. Describe processes that change rocks and the.

1. The contribution of minerals to rock composition.

2. Classify rocks by their process of formation.

3. Describe processes that change rocks and the surface of the earth.

More specifically:

1. Characteristics used to identify rocks2. Identify and describe the 3 major rock

groups.

A rock is a naturally occurring solid mixture of one or more minerals, or organic matter

Earth’s crust is made of rocks.

Rocks are classified by how they are formed, their mineral composition, and their texture

Rocks change over time through the rock cycle

1. Rocks are made of mixtures of minerals and other materials.

2. Ex: granite is made of the minerals quartz, feldspar, hornblende, and mica.

3. What is the difference between a rock and a mineral?

4. Mineral- is naturally occurring and cannot be made of once living things.

5. A rock can have minerals in it, but minerals will NEVER have rocks in them.

6. Scientists classify rocks by color, mineral composition, and texture.

1. A rock’s color provides clues to the rock’s mineral composition

2. Ex: granite is light-colored rock that has high silica content.

3. Ex: basalt is a dark colored rock that is low in silica.

1. Particles of minerals and other rocks that make up a rock are called grains.

2. Grains give the rock its texture- the look and feel of the rock’s surface.

3. Ex: smooth or rough, glassy or chalky.

4. Page 56

1. Grain sizea. Large and easy

to see- course-grained-ex: diorite

b. Small- fine grained- ex: slate

c. No visible grain- ex: flint

1. Grain shape results from the fragments of several rocks or the shapes of the crystals that form the rock.

2. Rounded grain- ex: conglomerate

3. Jagged grain- ex: Breccia

Conglomerate is determined by the shape of the fragments of other rock.

Granite is determined by the shape of the rock’s crystals.

1. Nonbanded- (nonfoliated) ex: quartzite- no grains b/c it cooled very quickly.

2. Banded- ( foliated) ex: gneiss- different colors in the bands.

1. What are the three ways geologists classify rocks?

2. What does banded and nonbanded mean?

3. What does course grained and fine grained mean?

4. Name an example of a rounded grain rock and a jagged grained rock?

1. Geologists classify rocks according to their origin (how they formed). Three groups are:a. Igneous Rocks- forms from cooling of magma/lava. Ex: granite and basaltb. sedimentary rock- forms when particles of other rocks are pressed and cemented together. Ex: conglomerate and limestonec. metamorphic rock- forms when a rock is changed by heat and pressure. Forms deep underground. Ex: gneiss and shale

Igneous rock begins as magma or molten rock.

Magma can form:▪ When rock is heated▪ When pressure is released▪ When rock changes composition

http://www.fi.edu/fellows/payton/rocks/create/igneous.htm

Intrusive Igneous Rocks: magma cools below (INSIDE) the Earth’s surface

Extrusive Rocks: forms when magma erupts OUTSIDE (EXIT) the Earth’s surface (lava), cools quickly with very small or no crystals formed

http://www.windows.ucar.edu/tour/link=/earth/geology/ig_intrusive.html&edu=high&fr=t

BASALT dark colored (mafic) forms from lava forms the ocean’s

crust (floor), shield volcanoes, and lava plateaus

It is the most common extrusive igneous rock.

GRANITE light colored (felsic) forms from magma forms the core of mtn

ranges It is the most

abundant intrusive rock in the crust.

Felsic: light colored rocks that are rich or high in silica(silicon and oxygen).

Mafic: dark colored rocks that are poor or low in silica.

Coarse-grained: takes longer to cool, giving mineral crystals more time to grow (bigger crystals)

Fine-grained: cools quickly with small or no crystals

Felsic

Mafic

Coarse-Grained

Fine-Grained

Granite

Gabbro Basalt

Rhyolite

Large crystals surrounded by small crystals.

Cools in two stage, quick then slow.Looks like Jello filled with fruit

Obsidian

What is Obsidian?

Obsidian is a dark-colored volcanic glass that forms from the very rapid cooling of molten rock material. It cools so rapidly that crystals do not form.

Obsidian is a dark-colored , smooth and shiny volcanic glass that forms from the very rapid cooling of molten rock material. It cools so rapidly that crystals do not form.

Is this rock Felsic or Mafic?

Is it fine-grained or coarse-grained?

Is this rock Intrusive or Extrusive?

Mafic, fine grained, extrusive

Minerals determine the color of rocks. Ex: Reddish granite is rich in feldspar

and is speckled pink. Hornblende and dark mica cause granite to be light gray with dark specks. Quartz makes with light gray or smoky specks.

Geologists take thin slices of granite and study them under the microscope to determine its mineral composition.

Igneous rocks are hard, dense, and durable. Thus the reason they were used in building materials.

Several ways igneous rocks have been used are: Egyptians used them to build statues Incas used them to build a fortress near their

capital city United States used them to build bridges and

buildings and to pave streets with cobblestones in the 1800’s and early 1900’s.

Basalt is used for gravel for construction and also for soil mixes.

Pumice is used for cleaning and polishing.

1. How are igneous rocks made?2. If a rock is course grained, did it

cool fast or slow? What about fine grained?

3. What are the two types of igneous rocks and where did they form?

Sediment includes small, solid pieces of rock, minerals, and organic matter such as shells, bones, leaves, and stems.

Water and wind deposit particles that form sedimentary rocks.

Running water, wind, and ice carry sediment from one place to another.

When sediments are pressed and squeezed together, compaction takes place.

When dissolved minerals naturally glue sediments together, cementation takes place.

Rock fragments that are carried by water eventually sink to the bottom of a lake or ocean.

http://www.fi.edu/fellows/payton/rocks/create/sediment.htm

Sedimentary rock is formed by erosion

Sediments are moved from one place to another

Sediments are deposited in layers, with the older ones on the bottom

The layers become compacted and cemented together which

then turn in to sedimentary rock.• This takes millions of years.

Sedimentary Rocks are formed at or near the Earth’s surface

No heat and pressure involved

Strata – layers of rock

Stratification – the process in which sedimentary rocks are arranged in layers

Geologists classify sedimentary rocks according to the type of sediments that make up a rock.

Three Types C – O- C 1. Clastic 2. Organic 3. Chemical Different processes form each type of

sedimentary rock.

Clastic – made of fragments of rock squeezed and cemented together with calcite or quartz.Breccia is a term most

often used for clastic sedimentary rocks that are composed of large angular fragments (over two millimeters in diameter).

The spaces between the large angular fragments can be filled with a matrix of smaller particles or a mineral cement that binds the rock together.

They are classified by the SIZE of the rock fragments.

EX: Tiny particles of clay is shale

Sandstone is small particles of sand

Conglomerate is different sized rock fragments.

Organic sedimentary – remains of plants and animals Ex: coal and limestone

Coal is an organic sedimentary rock that forms from the accumulation and preservation of plant materials, usually in a swamp environment. 

Coal is a combustible rock and along with oil and natural gas it is one of the three most important fossil fuels. 

Shells from living things pile up on the ocean floor in layers. Compaction and cementation change sediments to limestone.

Chemical sedimentary – minerals crystallize out of solution to become rock. Mineral deposits forms when seas or lakes evaporate.Limestone is also a

chemical sedimentary rock composed primarily of calcium carbonate (CaCO3) in the form of the mineral calcite. It most commonly forms in clear, warm, shallow marine waters.

It is usually an organic sedimentary rock that forms from the accumulation of shell, coral, algal and fecal debris.

Rock Salt crystallizes from the mineral halite.

Sandstone and limestone are soft enough to be cut easily into blocks or slabs. That’s why they have been used as building materials for thousands of years.

The White House in Washington D.C. is made of sandstone.

People use sandstone and limestone today to decorate or cover the outside of walls of buildings. Cement is made out of limestone.

1. How do sedimentary rocks form?2. Name the category for each rock:

clastic, organic, or chemical1. Coal2. Conglomerate3. Limestone

http://www.fi.edu/fellows/payton/rocks/create/metamorph.htm

Meaning to change shape

Changes with temperature and pressure, but remains solid

Usually takes place deep in the Earth

Contact Metamorphism – heated by nearby magma Increased temperature changes the composition of

the rock, minerals are changed into new minerals

Hornfeld is a fine-grained non-foliated metamorphic rock produced by contact metamorphism http://www.windows.ucar.edu/tour/link=/earth/geology/

meta_contact.html&edu=h igh&fr=t

Regional Metamorphism – pressure builds up in rocks that is deep within the Earth

Large pieces of the Earth’s crust collide and the rock is deformed and chemically changed by heat and pressurehttp://www.windows.ucar.edu/tour/link=/earth/geology/

meta_regional.html&edu=high&fr=t

Two Types 1. Foliated (banded) 2. Nonfoliated (nonbanded)

Foliated (banded) - contain aligned grains of flat minerals (it forms layers).

Gneiss is foliated metamorphic rock that has a banded appearance and is made up of granular mineral grains.

It typically contains abundant quartz or feldspar minerals.

Non-Foliated (nonbanded)– mineral grains are not arranged in plains or bands

Marble is a non-foliated metamorphic rock that is produced from the metamorphism of limestone.

It is composed primarily of calcium carbonate.

Determine if the following rock samples are foliated or non-foliated:

Amphibolite Quartzite Phyllite

Foliated

1. How do metamorphic rocks form?2. What does foliated and nonfoliated

mean?3. Give an example of a foliated rock

and a nonfoliated rock in that order.

www.brainpop.com Types of Rock Rock Cycle

http://www.youtube.com/watch?v=rkGVE6wNAzo - Mr. Lee

http://www.youtube.com/watch?v=lE3jR_RhxO4 – Mr. Parr