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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: