Minerals and Rocks. Rocks Aggregates (mixture—can be separated) of minerals.
MINERALS AND ROCKS THE TREASURES OF OUR EARTH! REVIEW THIS POWERPOINT OFTEN— IT IS EVERYTHING YOU...
-
Upload
sofia-caudle -
Category
Documents
-
view
215 -
download
1
Transcript of MINERALS AND ROCKS THE TREASURES OF OUR EARTH! REVIEW THIS POWERPOINT OFTEN— IT IS EVERYTHING YOU...
MINERALS AND ROCKS
THE TREASURES OF OUR EARTH!
REVIEW THIS POWERPOINT OFTEN—IT IS EVERYTHING
YOU NEED TO KNOW!
MINERAL:A. Naturally occurring
B. Inorganic, Solid
C. Crystalline structure
D. Definite chemical and
physical properties
E. Definite molecular structure
(internal arrangement of atoms)
Minerals are identified based on their physical properties 1. Color
• Most visible property, but least reliable.
• Many minerals have the same color and some have more than one color.
3. Luster• The way in which light is
reflected from the surface
a. Metallic - shines like polished metals, rust, heavy
b. Nonmetallic - no metallic luster
1) glassy, clear
2) pearly, white
3) greasy
4) dull
5) earthy
nonmetallic
metallic
4. Hardness
a. the resistance of a mineral is compared to glass by scratching it against a glass plate (5.5)
b. hardness of a mineral is determined by Moh's Scale of Hardness (1 – 10)
Other Properties:a. Magnetic
b. React with dilute
hydrochloric acid by
effervescing bubbles
c. Taste (salty)
d. Fluorescence
e. Double refraction
f. Radioactive
Minerals Relationship to Rocks:
• Minerals form rocks.
• Most rocks are composed of one or more minerals
• Monominerallic - composed of one mineral
• Polyminerallic - composed of more than one mineral
• 10 - 15 minerals form most all of the rocks on Earth, they are called rock-forming minerals.
Silicates minerals (SiO4)– two
minerals combine to form a compound.
• When they combine they create a structure called the Silicon-Oxygen Tetrahedron
3 Rock Types:Igneous Sedimentary Metamorphic
Rocks are classified based on their: Rocks are classified based on their: OriginOriginIn other words, what environment did they form in??? In other words, what environment did they form in???
CrystalsSediments
Recrystallizedcrystals
Igneous Rocks
Formed by cooling and solidification of
lava or magma.
Lava: extrusive
Magma: intrusive
C ourseG ra ined
FineG ra ined
G lassy
Fe lsic(L igh t co lored)
C ourseG ra ined
FineG ra ined
G lassy
M afic(D ark co lored)
Igneous rocks
A. Igneous RocksIgneous Rocks Intrusive- cools and solidifies from magma
(beneath Earth’s surface), making larger crystals due to slow cooling.
Granite (coarse crystal texture)
Extrusive – cools and solidifies from lava (at or near Earth’s surface), making smaller crystals due to faster cooling.
Obsidian (glassy texture) Pumice (glassy texture with vesicles)
Igneous Rock Characteristics
Felsic- forms light-colored rocks that are high in Al, low density.
Mafic- forms dark-colored rocks that are high in Mg and Fe, high density.
Vesicular- gas bubbles or air pockets.
Cooling Time Graph(the longer it takes to cool, the bigger the crystals!)
As time increases, crystal size increases.
What Minerals Are in the Rocks?First, identify the rock, then go straight down the column for the minerals.
Metamorphic Rocks
• Form from metamorphism (change) that is caused by heat and pressure.
• Usually form deep in the Earth's crust
• Causes a change in the rocks 1. makes the rock more dense2. separates the rock into layers (banding)
• Metamorphic rocks have been changed from a pre-existing rock.
• Caused by extreme heat and/or pressure. (regional)
• Happens over wide “regions.”• Caused by contact with extreme heat
from a nearby volcano (contact).• Occurs when the rock is in close
contact with volcanic heat.
Types of Metamorphic Rocks:
1. Contact Metamorphic - Rocks that form from being close to a heat source (magma)
2. Regional Metamorphic
a. caused mainly by pressure
b. usually cover large areas
c. form during tectonic activity
d. most metamorphic rocks are
formed from regional metamorphism
Metamorphism happens where lava or magma touches other rocks. What will this limestone rock metamorphose into?
Foliated Metamorphic Rock – mineral alignment
a. visible layers in the rock
b. form from extreme pressure which flattens the minerals into layers
c. different mineral densities may produce alternating light and dark bands of minerals (banding)
A “GNEISS” ROCK
Sedimentary Rocks form from sediments that go through cementation & compaction
EXAMPLES OF SEDIMENT SIZE FROM LARGEST TO
SMALLEST
Three main types
1. Clastic - made from other existing rock fragments. Clastic rocks are identified by the size of the fragments.
2. Chemical - form from minerals once dissolved in water.3. Organic - formed from once living organisms.
Features of Sedimentary Rocks:Stratification - layering of rocks caused by
different types of sediments being deposited
1. Made from sediments or rock material that has been broken down in some way.
2. Sedimentary rocks are usually formed under water.
3. Often layered.4. Are the only rocks that contain
fossils!
Key Features of Sedimentary Rock
5.Clastic (fragmental) –made by compaction and cementation of sediments.
• See Earth Science References Tables
Conglomerate Rock has rounded fragments
Rocks become rounded when they are exposed to water over longperiods of time, such as rocks formed at the bottom of a river bed.
Chemically formed rocks: Evaporites
1. Formed when water carrying minerals evaporates and leaves the minerals behind.
2. Are identified by the minerals present (such as halite forms Rock Salt)
• See Earth Science Reference Tables
• Bioclastic- •bio= life •clastic= fragments
• Made from accumulated shells (limestone) or plants (coal)
• See Earth Science Reference Tables