UNIT 2: ROCKS, SOIL & MASS MOVEMENTS. A concept map is a diagram showing the relationships among...

UNIT 2:UNIT 2:

ROCKS, ROCKS, SOIL & MASS SOIL & MASS MOVEMENTSMOVEMENTS

•A concept map is a diagram showing the relationships among concepts. ▫graphical tool for

organizing and representing knowledge

▫Concepts are represented as boxes or circles

▫Connected with labeled arrows in a branching structure.

CONCEPT MAPPING

CONCEPT MAP #1: Forces & Motion

Igneous, sedimentary, and metamorphic rocks are interconnected by a set of processes called the rock cycle. A

common path through the rock cycle is for igneous rock to be weathered,

transported and deposited to eventually become sedimentary rock. Then this sedimentary rock is subjected to high temperatures & pressures that turn it

into metamorphic rock. Eventually the metamorphic rock becomes new igneous

rock.

CONCEPT MAP #2: Matter & Energy

There are many factors that affect the appearance of a rock. For igneous

rocks, these factors include the composition and the rate of cooling. For sedimentary rocks, these include

the types of sediment compacted (clastic, chemical, biological). For

metamorphic rocks, these include the amounts of heat, pressure, and hot

fluids the rocks are exposed to.

What do you already know?•What is a rock?

•What are the three major types of rocks?

•What energy processes destroy and make new rocks?

Mineral Naturally occurring

inorganic solid with a definite

crystalline structure and

specific chemical composition

Rock•Naturally

occurring solid made of one or more minerals

•Rocks are classified based on the way they form.

Three Three Major Major

Types of Types of RocksRocks

1. IGNEOUS = formed when liquid magma cools and hardens

▫From the Latin ignis meaning born of fire

2. SEDIMENATRY = formed from

the sediments of other rocks

already present or very near

earth’s surface

Three Three Major Major

Types of Types of RocksRocks

3. METAMORPHIC = formed under high pressure and heat for long periods of time

The heat and pressure cause the rock to change into new rock.

Metamorphosism = change of form

Three Three Major Major

Types of Types of RocksRocks

SEDIMENTARY SEDIMENTARY ROCKROCK

METAMORPHIC METAMORPHIC ROCKROCK

IGNEOUS IGNEOUS ROCKROCK

HEAT & PRESSURE

SEDIMENTSEDIMENT

MAGMAMAGMA

MELT

MELT

ERODE & WEATHER

COMPACTION & CEMENTATION

ERODE & WEATHER

ERODE & WEATHER

MELT

HEAT & PRESSURE

COOL & HARDEN

THE THE ROCK ROCK CYCLECYCLE

IGNEOUS ROCK•Always begins as magma deep in the

earth. The magma cools and hardens into crystals deep in the earth or nearer to the surface.

•Classified by where they form, texture, and composition

Two Types of Igneous Rock

1. Intrusive = formed deep within the Earth• Examples: batholith, dike, sill, stock, laccolith

2. Extrusive = formed from lava at Earth’s Surface▫Examples: volcanic rock, pumice, obsidian

Two Types of Igneous Rock

Igneous Texture•Depends on the size of the crystals•Slower cooling = larger crystals

▫Intrusive rocks cool more slowly, creating larger crystals.

▫Called “coarse-grained”▫Example: granite

Igneous Texture•Faster cooling = smaller crystals

▫Extrusive rocks cool more quickly, creating smaller or no crystals

▫Called “fine-grained”▫No crystals = glassy or amorphous▫Examples: basalt, obsidian

QUESTION: WHICH IS MORE DENSE- BASALT OR GRANITE?

BASALT IS MORE DENSEthe ocean floor is made of it while the continental crust is made

mostly of Granite which is LESS DENSE! The Land will “float” on the ocean floor at subduction zones!

Igneous Texture•Porphyritic Texture: when magma

cools and harden under Earth’s surface, it can cool at different rates, causing varying crystal sizes. The result is called porphyritic.

•Larger crystals can even form on smaller crystals

Igneous Textures COARSE-GRAINED FINE-GRAINED

GLASSY PORPHYRITIC

Composition•What is it made of? What color is it?•Six mineral combinations: Quartz Feldspar Pyroxene Amphibole Olivine

Mica

• The combinations of the minerals determine the color of the rock.

Types of Marble

Examples of Igneous Rocks

1. Granite2. Rhyolite3. Gabbro4. Basalt5. Obsidian6. Pumice

Metamorphic Rock•Metamorphosis means change

▫So, metamorphic rock is changed ingenous or sedimentary rock

Agents of Metamorphism•Heat: changed occur between 100oC and

2000C•Pressure: Extreme pressures 12-16km

below Earth’s surface can change the crystalline structure, altering the type of rock

•Reaction to solutions (ex: hydrothermal vents)

Types of Metamorphism1. Contact Metamorphism=rocks are heated

through direct contact with magma or lava.2. Regional Metamorphism=occurs over a

large area.a. Is the most common type of metamorphismb. Widespread and intense heat and pressure deep in the earth cause

changes in the rock.

WHAT TYPE OF METAMORPHISM IS THIS EXAMPLE?

Classification of Metamorphic Rock

1. Foliated: Crystals are arranged in bands or layersa.Cleavage occurs along

these bands

2. Unfoliated: do not have bands of crystalsa.Do not cleave in layersb.Most contain 1 mineral

(ex: marble is nonfoliated rock made of calcite)

Examples of Metamorphic RockParent rock-

original rock before metamorphism

takes place

1.Slate (Shale)2.Gneiss (Schist, granite)3.Marble (Limestone)4.Quartzite (Sandstone)5.Schist (Phyllite)6.Anthracite

(Bituminous coal)

Sedimentary Rock•Sediments: form from

the breakdown of igneous, sedimentary, or metamorphic rocks at Earth’s surface▫ Deposited in layers, and

are compacted & cemented forming new rock.

▫ Can be reformed into igneous rock by subduction at deeps-sea trenches (returned to the interior of the earth)

Examples of Sedimentary Rocks

CLASTIC ROCKS

CONGLOMERATE

BRECCIA SANDSTONE SHALE SILTSTONE

Gravel size particles

Angular particles

Sand sized particles

Very fine Very very fine

Examples of Sedimentary Rocks

CHEMICAL BIOCHEMICAL

Limestone & Gypsum Coquina & Chalk

Precipitate from solution Shells and skeletons of marine organisms cemented

together

Sedimentary Rock•75% of all rocks on Earth’s surface

are sedimentary•Mainly made of mud, sand, and gravel•Moved by wind and water. Faster

wind or water can carry larger particles.

Sedimentary Rocks•Over millions of years mud, sand, grave,

bones, and shells settle to the sea floor as sediments.

•They pile up in layers of meters thick.

White Cliffs of Dover, England

Sedimentary Rocks•As sediments pile up,

the pressure becomes greater.▫What happens to the

sediments? The pressure squeezes

the sediment together, hardening it into rock.

•Results in rock layers or strata. This is the major characteristic of sedimentary rocks!

Features of Sedimentary Rock

1.Strata= layering of the rock when there is a change in the type of sediments deposited

2.Ripple Marks3.Mud Cracks4.Fossils= remains

of animals and plants preserved in the rock.

Examples of Sedimentary Rock

•Conglomerate•Breccia•Sandstone•Limestone•Rock salt

IGNEOUS METAMORPHIC SEDIMENTARY

How it’s formed:

Examples:

How does it change into other rock types? Explain thoroughly!!

Becoming Metamorphic:

Becoming Sedimentary:

Becoming Igneous:

Becoming Sedimentary:

Becoming Igneous:

Becoming Metamorphic:

At least 2 other facts: