Earth Materials

1. Environmental Geology Chapter 3 Earth Materials

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2. Basic Building Blocks

Atoms
Nucleus contains protons and neutrons
Electrons orbit the nucleus
Elements
Atoms with the same number of protons
Hydrogen has one proton, Helium has two
Periodic Table of Elements
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3. Basic Building Blocks

Isotope – an atom with varying number of
neutrons, some are unstable = radioactive decay
Ion – atom has gained or loss and electron and
is positively or negatively charged
Sodium Na+
Iron Fe 3+
Chlorine ClOxygen 02
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4. Basic Building Blocks

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5.

http://chemistry.about.com/library/pdfs/PeriodicTableMuted.pdf
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6. Basic Building Blocks

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7. Minerals

Naturally
occurring
Inorganic
1 or more element
Solid, crystalline
structure, atoms
in a fixed pattern
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8. Minerals

4,000+ minerals
Each has unique chemical and physical
properties (for ex. - graphite vs diamonds
are both almost all C but different
crystalline structures)
Physical properties controlled by structure
and composition
Building blocks of rocks
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9. Rock Forming Minerals

Approximately 12 common minerals make
up crust
Pyroxene and Amphibole are
ferromagnesian silicates
Feldspars – aluminum rich silicates
Clay minerals – result from weathering of
silicates, broken down by rainwater
Quartz – almost pure silicon and oxygen
Calcite - limestone
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10. Rock Forming Minerals

Minerals classified on type of negatively
charged ion within crystalline structure
Sulfides contain sulfur bonded to positive Pb,
Zn or Fe
Carbonates bonded to C and O
Oxides – negative charged O
Sulfates – negative charged SO4
Silicates – largest class, negatively charged Si
and O4
Si and O make up 75% of crust by weight
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11. Rocks

Aggregate or assemblage of one or more types of
minerals; many are composed of several different
minerals and some are one type of mineral
Texture is studied, way mineral grains are arranged.
Coarse, fine or mixed grains and shape of grain.
Formed when magma cools, minerals precipitate out
of solution; grains can grow. Or exposure to
heat/pressure.
Three types
1.
Igneous
2.
Sedimentary
3.
Metamorphic
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12. Igneous Rocks

Form via cooling magma
Intrusive cooled
Coarse grained
Extrusive cooled
Fine grained
When magma breaches Earth’s surface it is called lava.
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13. Weathering

Breaking down of rocks
Physical weathering
Frost wedging
Plant roots
Crystal growth – minerals precipitate out of solution
Fluctuations in daily temperature
Chemical
Dissolution
Hydrolysis
Oxidation / reduction
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14. Physical Weathering

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15. Chemical Weathering

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16. Sedimentary Rocks

Weathering results in sediment
Compacted and cemented sediment =
sedimentary rocks
Erosion – sediment and ions removed
from given area.
Rock or sediment dissolved, picked up by
wind or water, or abraded
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17. Two Types of Sedimentary Rocks

1.
Detrital – made of preexisting rock & mineral
fragments that have cemented together
Material was deposited in low lying areas
Shale, sandstone
Table 3.2, page 80
2.
Chemical – dissolved ions precipitate out of
solution
Limestone, rock salt (halite)
Table 3.3, page 81
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18. Sedimentary Rocks

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19. Metamorphic Rocks

Changes through heat and pressure, not
enough to melt rock.
Contact metamorphism
Heat, low pressure
Nonfoliated texture, marble and quartzite
Regional metamorphism
heat, high pressure
Foliated texture due to pressure. Minerals reorient
into parallel structure. Slate and gneiss.
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20. Contact Metamorphism

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21. Regional Metamorphism

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22. Foliation

Figure 3.27, page 84
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23. Rock Cycle

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24. Rocks as Indicators of the Past

Figure 3.30, page 87
Figure 3.31, page 88
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25.

Minerals
1A sulfur
2A native copper
3A graphite
4A galena (lead sulfide)
6A pyrite (fool’s gold)
7A hematite
9A magnetite
11A halite
13A calcite
18A feldspar
20A quartz
21 A quartz
23 A mica, muscovite
Rocks
1B granite
2B granite, pegmatite
5B gabbro (oceanic crust)
8B basalt
12B obsidian
13B volcanic breccia
15B sandstone, siliceous
16B sandstone, arkose
17B shale
20B limestone, chalk
22B limestone, travertine
24B coal, bituminous
25B slate
30B quartzite
31B marble
32B anthracite coal
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