Johanna Kovarik USDA Forest Service Minerals and Geology Management.
ES 9A.STUDENTS KNOW THE RESOURCES OF MAJOR ECONOMIC IMPORTANCE IN CALIFORNIA AND THEIR RELATION TO...
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Transcript of ES 9A.STUDENTS KNOW THE RESOURCES OF MAJOR ECONOMIC IMPORTANCE IN CALIFORNIA AND THEIR RELATION TO...
ES 9A.STUDENTS KNOW THE RESOURCES OF MAJOR ECONOMIC IMPORTANCE IN CALIFORNIA
AND THEIR RELATION TO CALIFORNIA’S GEOLOGY.
Ch 5. Minerals
Characteristics of Minerals
To be a mineral, a substance must have four characteristics:
must be inorganic—it cannot be made of or by living things;
must occur naturally—it cannot be man-made;
must be a crystalline solid; must have a consistent chemical
composition.
Kinds of Minerals
All minerals can be classified into two main groups — based on their chemical compositions.
silicate mineral contains a combination of silicon and oxygen, may also contain one or more metals
Silicate minerals make up 96% of Earth’s crust.
nonsilicate mineral does not contain compounds of silicon and oxygen
Make up about 4% of Earth’s crust.
Physical Properties of Minerals
Coloris unreliable for the identification of minerals.can be affected by impurities or by weathering
processes.
Streakthe color of a mineral in powdered formdetermined by rubbing some of the mineral
against an unglazed ceramic tile called a streak plate.
Lusterthe way in which a mineral reflects light
metallic luster if it reflects light
All other minerals have nonmetallic luster.
Ex. glassy, waxy, pearly, brilliant, and earthy.
Cleavagethe tendency of a mineral to split along
specific planes of weakness to form smooth, flat surfaces
Fracturethe manner in which a mineral breaks along
either curved or irregular surfaces
Physical Properties of Minerals
Hardnessthe ability of a mineral to resist scratching
is called hardness.
Mohs hardness scale the standard scale against which the hardness of minerals is rated.
The strength of the bonds between the atoms that make up a mineral’s structure determines the hardness of a mineral.
STUDENTS KNOW HOW TO EXPLAIN THE PROPERTIES OF ROCKS BASED ON THE PHYSICAL
AND CHEMICAL CONDITIONS IN WHICH THEY FORMED, INCLUDING PLATE TECTONIC PROCESSES
Ch 6 ROCKS
Three Major Types of Rock
Rock: The material that makes up the solid parts of Earth.
Rocks are classified based on the processes that form.
3 Types of Rocks
1. Igneous rock forms when magma, or molten rock, cools and hardens.
2. Sedimentary rock forms when sediment deposits that form when rocks, mineral crystals, and organic matter have been broken into fragments are compressed or cemented together.
3. Metamorphic rock forms when existing rock is altered by changes in temperature, pressure, or by chemical processes.
Chapter 6The Rock Cycle
Geologic forces and processes cause rock to change from one type to another.
rock cycle the series of processes in which rock forms, changes from one form to another, is destroyed, and forms again by geological processes
Chapter 6The Formation of Magma
igneous rock rock that forms when magma cools and solidifies
The three factors that affect whether rock melts include
1) temperature, 2) pressure,3) the presence of fluids in the rock.
Chapter 6The Formation of Magma, continued
Partial MeltingDifferent minerals have different melting points
As the temperature increases and as other minerals melt, the magma’s composition changes.
Chapter 6The Formation of Magma, continued
Fractional Crystallization
The crystallization and removal of different minerals from the cooling magma.
Minerals that have the highest freezing points crystallize first.
Chapter 6Textures of Igneous Rocks
intrusive igneous rock rock formed beneath Earth’s surface
extrusive igneous rock rock formed at Earth’s surface
Chapter 6Textures of Igneous Rocks, continued
Coarse-Grained Igneous RockBecause intrusive igneous rocks cool slowly, they
commonly have large mineral crystals.
Fine-Grained Igneous RockBecause extrusive igneous rocks cool rapidly, they
are commonly composed of small mineral grains.
Sedimentary Rock
1. Rocks, mineral crystals, and organic matter that have been broken into fragments .
2. Sediment is carried away and deposited by water, ice, and wind.
3. Sediment deposits are compressed or cemented together and harden they form sedimentary rock.
Section 3 Sedimentary RockChapter 6Chemical Sedimentary Rock
chemical sedimentary rock sedimentary rock that forms when minerals precipitate from a solution or settle from a suspension
Section 3 Sedimentary RockChapter 6Organic Sedimentary Rocks
organic sedimentary rock sedimentary rock that forms from the remains of plants or animals
Section 3 Sedimentary RockChapter 6Organic Sedimentary Rocks,
continuedThe diagram below shows the formation of organic limestone.
Section 3 Sedimentary RockChapter 6Clastic Sedimentary Rock
clastic sedimentary rock sedimentary rock that forms when fragments of preexisting rocks are compacted or cemented together
Chapter 6Formation of Metamorphic Rocks
One type of rock changes into metamorphic rock because of chemical processes or changes in temperature and pressure
Heat, pressure, and hot fluids cause some minerals to change into other minerals.
Chapter 6Formation of Metamorphic Rocks, continued
Contact MetamorphismA change in the texture, structure, or
chemical composition of a rock due to contact with magma
Regional Metamorphism
A change in the texture, structure, or chemical composition of a rock due to changes in temperature and pressure over a large area, generally are a result of tectonic forces
Chapter 6Classification of Metamorphic Rocks
Foliated RocksMinerals grains are arranged in planes or
bands
Extreme pressure may cause the mineral crystals in the rock to realign or regrow to form parallel bands.
Chapter 6Classification of Metamorphic Rocks, continued
Nonfoliated RocksMinerals grains are not arranged in
planes or bands