3 Oct 2025

1. What makes some rocks more “valuable” than others?

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1. Give 2 examples of something that could be considered a MINERAL.

PHYSICAL

RESOURCES

MINERALS

COLOR – Easily observable; not good for mineral identification.

• Weathering changes color
• Minerals have many different colors
• Many minerals have similar colors

LUSTER – the way light is reflected from the surface of a mineral.

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Two main types of luster:

1. metallic
2. non-metallic

STREAK – Color of powdered form of mineral. Rub mineral on an unglazed plate.

CLEAVAGE – describes the way a mineral breaks

Cleavage: Flat, even break (ex. Mica)

Fracture: Jagged, rough break (ex. Sulfur)

HARDNESS – The ability of a mineral to resist being scratched

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Mohs Hardness Scale: from one to ten

• 1 is the softest

(ex. Talc)

• 10 is the hardest

(ex. Diamond)

CRYSTAL SHAPE – minerals will form one of six basic shapes

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Each mineral will always form the same shape because of the way the atoms combine in a geometric pattern.

DENSITY – Ratio of mass to volume (specific gravity) D=M/V

SPECIAL PROPERTIES –

MAGNETISM

magnetic (ex. Magnetite

FLUORESCENCE

glowing under black light

(ex. Fluorite)

PHOSPHORESCENCE

continues to glow once the

black light is turned off

DOUBLE REFRACTION

double images (ex. Calcite)

RADIOACTIVITY

SMELL

(ex. Sulfur)

REACTION WITH ACID

(ex. Calcite)

Create a detailed sketch of the rock cycle that shows:

• 3 main rock types
• Two intermediates

(substances needed BEFORE the rock type forms)

• Names of processes clearly identified on each arrow in your sketch

EASY

Hmmm…

Say WHAT??

6 Oct 2025

ROCKS!!

The Rock Cycle

Hot, molten rock or MAGMA is the parent material for all rocks. Based on the studies of geologists, rocks are classified into 3 major groups.�

1. IGNEOUS:

• means “from fire”
• forms when magma cools and hardens

2. SEDIMENTARY:

• made from sediments (fragments of other rocks)
• sediments harden to form rock

3. METAMORPHIC:

• means “changed form”
• heat and pressure change existing rock into a new type

Any of the three major rocks can be CHANGED into any other type. Various GEOLOGICAL forces and processes cause rock to change. This series of changes is called the ROCK CYCLE.

Cooled and hardened MAGMA forms IGNEOUS rock. Once this rock has formed, earth’s processes begin to break down the rock into smaller pieces called SEDIMENTS.

Sediments are then COMPACTED and hardened together to form SEDIMENTARY rock.

If these sedimentary rocks are subjected to great HEAT and PRESSURE they then become METAMORPHIC rocks.

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If heat and pressure are even more intense, the METAMORPHIC rock melts to become MAGMA.

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***A rock does NOT always pass

through each of the rock cycle**

Igneous Rocks

There are 2 types of igneous rocks. They are classified according to where the molten rock COOLS and HARDENS. 

INTRUSIVE - magma cools below surface

EXTRUSIVE - magma cools above surface

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Igneous Rocks can be Classified Two Ways – by TEXTURE and by COMPOSITION.

EXTRUSIVE IGNEOUS ROCK forms when magma cools above the surface of the earth. It cools quickly so no (or very small) crystals have time to form.

TEXTURE of Igneous Rocks: (crystal size)

INTRUSIVE IGNEOUS ROCK forms when magma cools below the surface of the earth. It cools slowly so very large crystals have time to form

PORPHYRY rocks start out cooling below surface and then cool above surface.

1. How are rocks classified?

(put into the 3 groups based on ….)

2. Igneous rocks are made from ________
3. Sedimentary rocks are made from _____________.
4. Metamorphic rocks are made from ______________________.
5. Name the 2 types of igneous rocks.

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(what do those types MEAN?)

How they are made

magma

sediments

Other rocks that undergo extreme heat & pressure

Intrusive & extrusive

Intrusive – formed INSIDE Earth

Extrusive – formed ON SURFACE of Earth

7 Oct 2025

Sedimentary Rock

Sedimentary rock is made up of accumulations of various types of SEDIMENTS. COMPACTION and CEMENTATION are the processes that from sedimentary rock.

Geologists classify sedimentary rocks according to the KIND AND SIZE OF SEDIMENTS THAT FORM THEM.

Clastic Sedimentary Rock:

Classified by size of sediments they contain.

FORMATION OF SEDIMENTARY ROCK

• CONGLOMERATE: Gravel-sized fragments

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• SANDSTONE: Sand-sized particles
• SHALE: Clay-sized particles

Chemical Sedimentary Rock:

EVAPORITES: Water evaporates and leaves behind minerals that were dissolved in the water.

Organic Sedimentary Rock:

COAL: Forms from decayed remains of plants

CHALK: Animal shells build up and form a hardened calcium deposit.

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STRATIFICATION

RIPPLE MARKS

MUD CRACKS

FOSSILS

GEODE

`

Metamorphic Rock

The changing of one type of rock to another by heat, pressure, and chemical processes is called METAMORPHISM.

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FORMATION OF METAMORPHIC ROCK:

During metamorphism HEAT, PRESSURE, and HOT FLUIDScan cause certain minerals to change into other chemicals.

2 types of metamorphism occur in the earth’s crust.

CONTACT Metamorphism: rock are near or actually touching the hot magma

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REGIONAL Metamorphism: rocks changed over an area of 1000s of km due to periods of tectonic activity

Metamorphic rocks are classified according to their STRUCTURE. Metamorphic rocks have either a FOLIATED or UNFOLIATED texture.

CLASSIFICATION OF METAMORPHIC ROCK:

FOLIATED: Visible parallel bands of minerals

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Common foliated rocks are: SLATE, SCHIST, and GNEISS.

Shale 🡪 SLATE 🡪 SCHIST 🡪GNEISS

SHALE

SLATE

SCHIST

GNEISS

UNFOLIATED: Do not have bands of crystals.

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Common unfoliated rocks are: MARBLE and QUARTZITE.

 Sandstone 🡪 QUARTZITE

Limestone 🡪 MARBLE

🡪

🡪

1. Glue the Rock Type Organizational Chart into your Warm-Up Book.

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• Use the word banks at the bottom to fill in the missing information.

8 Oct 2025

IGNEOUS

METAMORPHIC

Intrusive

Extrusive

Lg Crystals

Granite

Sm Crystals

Obsidian

Intrusive & Extrusive

Porphyry

Clastic

Shale

Sandstone

Conglomerate

Evaporites

Rock Salt

Rock Gypsum

Organic

Coal

Limestone

Foliated

Striped

Slate

Schist

Gneiss

Unfoliated

No Stripes

Marble

Quartzite

Contact

Contact with magma

Regional

in area of large pressure

Weathering, Soil, & Erosion

Weathering Processes:� �The change in PHYSICAL or chemical COMPOSITION of rock materials exposed at the Earth’s surface is called WEATHERING.

FOUR TYPES OF MECHANICAL WEATHERING:

EXFOLIATION:

rocks peeling away

from underlying

rocks in sheets

ICE WEDGING:

• Water seeps into cracks & joints
• Water freezes 🡪 expanding 10 times
• Water thaws & process repeats

ORGANIC ACTIVITY:

• roots of plants breaking apart rocks

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• digging into rocks by burrowing

ABRASION:

• collision of one rock with another
• caused by gravity, water, and wind

Chemical Weathering: (5 types)

Chemical weathering or DECOMPOSITION, occurs when chemical reactions take place between the MINERALS in the rock and WATER, CARBON DIOXIDE, OXYGEN, and ACIDS.

HYDROLYSIS:

• change in composition of minerals when they react with water
• LEACHING- water carrying dissolved minerals to lower layers of rock

CARBONATION:

When CO₂ from the air dissolves in WATER, a weak ACID solution called CARBONIC ACID forms.

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• H₂O + CO₂ 🡪 H₂CO₃
• minerals combining with H₂CO₃.
• combines with calcite and dissolves limestone.

OXIDATION:

• metallic elements combine with oxygen
• Ex.) 4Fe + 3O₂ 🡪 2Fe₂O₃

ACID PRECIPITATION:

• in some areas Nitrogen and Sulfur combine with water.
• this greatly accelerates weathering

PLANT ACIDS:

acids produced by lichens and moss can dissolve some rocks.

Rates of Weathering

Rocks do not weather at the same rate. Different rates of WEATHERING produce different FORMATION. This rate depends on a number of FACTORS.

Rock Composition:

The COMPOSITIONof rocks is a major factor in the rate of WEATHERING. Often IGNEOUS and METAMORPHIC rock remain unchanged after the sedimentary rock has WEATHERED away.

• Most resistant to weathering: QUARTZ (weathers the most slowly)
• Least resistant to weathering: LIMESTONE (weathers the fastest)

Climate:

• In general RAINFALL and the FREEZE/THAW process produced by the alternating HOT and COLD weather have the GREATEST effect on the rate of weathering.
• HOT/DRY CLIMATES: no water, therefore weathering is slow because NO chemical weathering
• COLD CLIMATES: also very slow because most water is frozen
• WARM/HUMID CLIMATES: rapid weathering due to moisture, which allows for chemical weathering

Topography:

The topography of the land, or the ELEVATION and SLOPE of the surface, influences the rate of WEATHERING.

• Because it’s colder at HIGHER elevations, ICE WEDGING increases.

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• On STEEP SLOPES, such as mountainsides, weathered rock fragments are pulled downhill by GRAVITY.

Name at least TWO commonly seen examples of weathering and DESCRIBE them.

1. Plant roots crack sidewalk
2. Holes in street (potholes) because water seeps into ground and freezes. Ice gets bigger when it freezes & cracks the ground.
3. Water running downhill carves a gully (ex. Grand canyon)
4. Gravity can break rocks as they fall downhill

9 Oct 2025

WEATHERING AND SOIL

Soil Composition:

The rock material consists of 3 main types: (classified by SIZE)

• CLAY: too small to be seen (rich in feldspar)
• SAND: large enough to be felt/seen (quartz and granite)
• SILT: gritty feel, too small to see (carried along rivers)

SOIL TEXTURE TRIANGLE shows the percent composition of

each of the three component parts of soil.

What type of soil is 30% sand,

40% silt, and 30 % clay?

Soil Profile:

CLIMATE is one of the most important factors in formation of SOIL.

Soil varies in composition, texture, structure, and color at different depths.

These differences help divide the soil into zones known as HORIZONS.

A side view of these horizons create a soil PROFILE.

O Horizon: organic matter that has fallen on the ground

A Horizon: topsoil (aka humus). This is the zone where surface water leaches into the layers below.

B Horizon: subsoil (aka regolith). Layer immediately below the topsoil.

This layer gets nutrients through the process known as LEACHING, when water flows through the topsoil and pulls nutrients down with it.

C Horizon: partially weathered rock. This is the bottom layer of soil. Below it is solid bedrock.

Soil and Topography:

Because rainwater runs DOWNSLOPE, much of the TOPSOIL is washed away.

Soil at the TOP and BOTTOM of the hill tends to be THICKER than soil on the slope itself.  

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A fairly FLAT area with good DRAINAGE provides the best surface for formation of thick, FERTILE soil.

Erosion:

The process by which the products of weathering are MOVED is called EROSION.

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• Soil erosion occurs SLOWLY worldwide.
• climatic conditions and HUMANS can cause this to happen faster.

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SOIL

WEATHERING

3 Particles

Chemical

1. H

2. Acid rain

3. Acid from

plant roots

1. A

2. wedging

3. O

activity

1. C

2. S

3. S

1. C

2. T

3. T

small

large

Mechanical

2 Types

Soil Profile

Partially weathered rock

subsoil

topsoil

organic

ydrolysis

brasion

Ice

rganic

lay

ilt

and

limate

ime

opography

10 Oct 2025

Soil Formation

Depends on

THIS IS THE MISSING SLIDE!!!

Accelerated Soil Erosion:

Unwise FARMING and RANCHING methods increase soil erosion. For example, clearing TREES and allowing animals to OVER-GRAZE destroy the soil protection of plants.

Three Examples of Accelerated Soil Erosion:

FURROWING: land where water can run over in channels

GULLYING: deeper furrows

SHEET EROSION: stripping away of topsoil

GULLYING

SHEET EROSION

Soil Conservation:

• STRIP CROPPING: crops planted in alternating bands

CONTOUR PLOWING: soil plowed in circular motion with the lay of the land

TERRACING: step-like ridges in sides of hills

CROP ROTATION: planting one crop one year and a different one next year

Gravity and Erosion:

The movement of fragments DOWNHILL is MASS MOVEMENT.

TALUS: rock fragments that gather at the bottom of the slope.

Rapid Mass Movement:

ROCKFALLS: rocks falling from a steep cliff

LANDSLIDE: loose rock and soil moving down a slope

Example of Landslide in China 10/5/2025

MUDFLOW: rapid movement of mud

SLUMP: large block of soil moving downhill in one piece

Slow Mass Movements:

SOLIFLUCTION: “soil flow”. Surface layer becomes saturated when snow thaws

CREEP: extremely slow downhill movement of weathered rock material

THE END

EROSION

Accelerated Erosion

Mass Movements

Soil Conservation

Fast

Slow

1.

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2.

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3.

1.

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2.

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3.

1.

​

2.

​

3.

4.

1.

4 Agents of Erosion

1.

​

2.

​

3.

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4.

rockfall

landslide

mudflow

slump

creep

gully

clearing out all trees

sheet erosion

contour plowing

crop rotation

cover plants

wind

water

gravity

glaciers

14 Oct 2025

Copy and complete:

1. Gravestones weather over time due to _______________________________.

2. What are some of the human activities that increase the rate of erosion?

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3. A soil’s texture is determined by its ______________ using the ________________.

chemical weathering

clearcutting of forests

overgrazing of animals

% sand, silt, clay

soil texture triangle

15 Oct 2025

1. The transport of weathered materials by a moving natural agent is called _______________.

2. The 4 agents of erosion are glaciers, gravity, wind and ______________.
3. Creep, rockfalls, and landslides are examples of _____________________________.
4. Farmers plow up and down a hill in a form of accelerated erosion known as ______________.

Copy and complete:

erosion

water

mass movement

furrowing

16 Oct 2025

1. What are the five things that determine if a substance is a mineral?

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1. Is a pearl a mineral? WHY or WHY NOT?

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3. Is a diamond a mineral ? WHY or WHY NOT?

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4. What is the difference between cleavage and fracture?

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5. What determines the hardness & crystal structure of a mineral?

Solid, Naturally Occuring, Inorganic, Fixed Crystal Pattern, Element /Compound (SNIFE)

No – it’s not Inorganic (it’s made from a living thing)

Yes – it’s solid, natural, inorganic, fixed pattern & element

Cleavage = flat, even break Fracture = uneven, jagged

It’s chemical formula. That determines how it’s formed and those bonds set the hardness.

16 Oct 2025

You find yourself in charge of the new construction project at the corner of Carpenter Upchurch & Morrisville Parkway (across from Carpenter Elementary).

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What PREVENTIVE measures should you put in place to minimize soil erosion and sediment pollution to the nearby creeks and water systems?

1. Pack the soil (steamroller)
2. Silt fences (short plastic fence)
3. Wet the soil (water spraying trucks)
4. Plant vegetation as quickly as possible

BONUS