Download Chapter 15 Part 1 Power Point File

Earth
Chapter 15
1
Overview
•
Earth science
Can be broadly defined as the
investigation of interactions among the
four components of the earth:
1. Atmosphere (Air, Weather)
2. Hydrosphere (Water, Ice)
3. Biosphere (Plants, Animals)
4. Geosphere (Land, Rocks)
2
Solid Earth materials
• Thin surface crust
– Mostly lighter
elements
– 8 elements
make up 98.6%
of crust
– Rocks and
minerals make
up solid crust
materials
3
Solid Earth
Materials
• Non-uniform
distribution of matter
• Molten core
– Contains most heavy
elements
– Iron, nickel
4
Minerals
• Mineral
– a naturally occurring solid
element or compound with a
constant chemical
composition in a crystalline
structure
– Cannot be synthetic
– Must have regular,
repeating pattern
• Example: Halite (NaCl)
5
Crystals
•
•
All minerals can be classified on the basis of
whether the mineral structures contain these 2
elements:
• Silicon and Oxygen
2 main groups
1.
2.
Silicates
Nonsilicates
6
Silicates
• Contain mostly silicon and
oxygen
• Make up 92% of Earth’s
crust
• Based on silicon-oxygen
tetrahedral unit
• (SiO4)-4
7
Silicates
• Two subdivisions
1. Ferromagnesian silicates
• iron, magnesium,
calcium and other
elements
• Greater density, darker
color
• Ex: augite, hornblend.
olivine
2. Nonferromagnesian
silicates
• Lighter color, lower
density
• Ex: muscovite,
feldspars, quartz
8
Silicates
9
Nonsilicates
• No silicon-oxygen tetrahedrons in crystalline
structure
• Make up remaining 8% of Earth’s crust
• Eight groups of nonsilicates
1. Carbonates
•
2.
3.
4.
5.
6.
7.
8.
Most abundant
Sulfates
Oxides
Sulfides
Halides
Phosphates
Hydroxides
Native elements
10
Silicates and Nonsilicates
11
Rocks
• Aggregation of one or more minerals and perhaps
other materials
• Minerals are physically combined to make rocks
• Most rocks are silicate minerals (92 %)
12
Rocks
• Classification scheme
– Based on how rocks
were formed
– Three main groups
1.Igneous
2.Sedimentary
3.Metamorphic
13
Igneous Rocks
• Formed from magma
above or below
Earth’s surface
• All rocks were at one
time igneous rocks
• ~2/3 earth’s crust
made up of igneous
rock
14
Igneous Rocks
• Granite
– Light colored
– Made up of 3 silicate
minerals
• Quartz, mica,
feldspar
– Visible grains
• Basalt
– Most common volcanic
rock
– Dark, more dense
– Grains too tiny to see
15
Basalt
16
Idaho
Basalt rock
17
Granite
18
19
Pumice
20
Obsidian
21
Sedimentary rocks
• Formed from particles or dissolved materials from
previously existing rocks
• Sediments
– Accumulations of silt, sand or other materials that settled out of
water
22
23
24
25
Nitrification
• The rock-forming process
• Two main parts
1. Compaction
• Reduces thickness of
deposit
• Squeezes out water
2. Cementation
• Spaces between sediment
particles filled with
chemical deposit
• Chemical deposit binds
particles together
26