EARTH MATERIALS

1
EARTH MATERIALS
2
Review Plate Tectonics

• What is the key figure from Chapter 2?

A
B
D
C
3
Importance of Rocks Minerals
4
Basic Chemistry Review (1)

• All matter, including minerals and rocks, made of
  atoms
• Atom structure Nucleus (proton and neutron) and
  surrounding electrons
• Atomic number The unique number of protons in an
  elements nucleus
• Atomic mass number The sum of the number of
  protons and neutrons
• Isotopes same of protons, but differing
  neutrons

5
Basic Chemistry Review (2)
6
Earth Materials - Elements

• Only Silly Asses In College Study Past Midnight
• Oxygen
• Silicon
• Aluminum
• Iron
• Calcium
• Sodium
• Potassium
• Magnesium

(0)
(-)
7
Mineral Definitive Properties

• Compounds of elements
• Quartz (SiO2)?

Coal (C)?
Diamond (C)?
Ice (H2O)?
8
Rock-Forming Mineral Groups
9
Rocks
10
The Rock Cycle

• Start anywhere!
• Igneous (primary)

11
The Rock Cycle

• Start anywhere!
• Igneous (primary)
• Weathering and erosion
• Sediments
• Sed. Rocks
• Meta. Rocks (secondary)
• Note alternate paths

12
Igneous Rocks
13
Igneous Rock Texture (1)

• Dictated by the rates of magma cooling
• The rates of cooling are slower beneath the
  surface, much faster near or at the surface
• The slower the magma cools, the coarser the
  mineral particles in igneous rocks
• Igneous rocks formed from two stages of cooling
  have distinctive, different-sized particles We
  have words for that!

14
Igneous Rock Composition

• Depending on the composition of magma
• Felsic Silica rich, typically related to
  continental crust
• Intermediate Commonly associated with convergent
  boundaries along the rim of Pacific
• Mafic Silica poor, usually related to the
  oceanic crust
• Usually characterized by color felsic light
  and mafic dark

15
Igneous Rocks
Light(Si-rich)
Dark(Si-poor)
Intermediate
Basalt
Fine (Volcanic/ extrusive)
Andesite
(Rhyolite)
Granite
(Diorite)
(Gabbro)
Coarse (Plutonic/ intrusive)
16
Sediments

• Particle Size
• Very fine (Clay)
• Fine (Silt)
• Moderate (Sand)
• Coarse (Pebbles)
• Very coarse (Cobbles, boulders)
• Dissolved materials (leached from soils)

17
Sedimentary Rocks
Claystone
Siltstone
Sandstone
Conglomerate
Shale (mudstone)
Chert
(Sinter)
Limestone
(Travertine)
18
Sedimentary Structure and Environment

• Stratification layering, evidence of process
• Cross-bedding Movement direction of ancient
  currents
• Fossil content Environment setting (continental,
  marine, or transitional)
• Fine-grained clastic rocks and limestone in humid
  region very weak rocks (shale) causing
  environmental problems

19
Metamorphic Rocks
20
Metamorphic Rock Texture

• Foliation Preferred alignment of platy mineral
  particles
• Slaty, schistosity, gneissic banding
• Typically classified by texture Slate, schist,
  gneiss
• Nonfoliated Random arranged and interlocked
  mineral particles
• Fine-grained, coarse-grained
• Typically classified by composition Marble,
  quartzite

21
Metamorphic Rocks
Slate
Schist
Gneiss
Granite
Quartzite
Marble
(Greenstone)
22
Rock Occurrence

• What you see isnt what you get!

23
Surface rock distribution

• Rocks are where its at!
• 1872 Mining Law?

24
Fundamental Stratigraphic Principles

• Three fundamental principles in understanding the
  relationships of rocks and Earth history
• The law of crosscutting relationships rock is
  younger than the ones that it cuts
• The law of original horizontality sedimentary
  rock layers nearly horizontal under normal
  conditions
• The law of superposition rocks become
  progressively younger towards the top in an
  undisturbed and undeformed rock sequence

25
Rocks and Environment
26
Rock Structure Strength
27
Rock Structure (1)

• Brittle deformation Fractures, joints, and
  faults
• Conduits for fluids, possibly pollutants
• Weak surfaces for landslide, earthquake, and
  failures of infrastructure

28
Rock Structure (1)

• Brittle deformation Fractures, joints, and
  faults
• Weak surfaces for landslide, earthquake, and
  failures of infrastructure

29

• Ductile deformation Folds
• Mountainous terrain

30
Rock Structure (2)

• Unconformity Contact of rock units representing
  geologic time gap
• Types nonconformity, angular unconformity, and
  disconformity
• Clues for ancient geologic environment

31
Applied and Critical Thinking Topics

• What rock type is most likely to cause
  environmental problems (groundwater, slope
  stability, foundation failure)?
• Granite
• Sandstone
• Shale
• Gneiss
• Marble