Mineral Classification

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Mineral Classification

• Mineral Classification -- Minerals are classified
  based on their anions.
• Halides Cl- or F-
• Oxides O2-,
• Sulfides S2-,
• Carbonates (CO3)2-
• Sulfate (SO4)2-
• Silicates networks of (SiO4)4- tetrahedra.

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Silicate Classification

• All silicates are made of the same general
  elements, Metallic ions bound to Silicate ions
  that are arranged in different structures
• The properties of the minerals are controlled by
  the silicate structures.

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Important, rock-forming minerals

• Halides - Halite - NaCl
• Sulfates --
• Anhydrite -- CaSO4
• Gypsum -- CaSO4 2H2O
• Carbonates
• CaCO3
• CaMg(CO3)2

• Silicates
• Ferromagnesian
• Olivine
• Pyroxene
• Amphibole
• Biotite
• Nonferromagnesian
• Quartz
• Plagioclase Feldspar
• Potassium Feldspar
• Muscovite
• Clays

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Review

• Defined the term mineral
• Defined the following terms
• proton atomic mass number
• ionic bond covalent bond
• oxide silicate tetrahedron
• Named the physical properties that can be used to
  describe minerals.

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Igneous Rocks and Intrusions

• Physical Geology 3101

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Igneous Rocks and Intrusions

• Igneous Rocks
• Formation
• Descriptions
• Classification
• Igneous Intrusions
• Intrusive Bodies
• Intrusive Processes

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Rocks and the Rock Cycle

• Rock -- a solid mass of natural material, usually
  made of minerals or particles stuck together.
  Assemblage of minerals. (My definition a
  seismo-acoustic propagator)
• Rock cycle -- a way of thinking about the
  different kinds of rocks and how they relate to
  each other.

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Igneous Rocks

• Cooled from melt, magma or lava
• There are two types of igneous rocks, that are
  differentiated by how they occur.
• Intrusive Rocks -- form when magma solidifies
  beneath the earths surface --big crystals
• Extrusive Rocks -- form when magma solidifies on
  the earths surface (at volcanoes) small or no
  crystals.

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Remember the Rock Cycle
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Igneous Rocks

• Igneous Rocks
• Formation
• Description
• Classification

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What are Magma and lava?

• Definition
• Magma - molten rock beneath surface
• Lava - molten rock at the surface
• Composition
• felsic - gt65 SiO2, much Na, K
• intermediate
• mafic - lt 52 SiO2, much Mg, Fe
• Temperature - 900 C to 1350 C
• Viscosity - resistance to flow

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Description of Igneous Rocks

• Igneous Rocks are described by their texture and
  composition.

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Igneous Compositions

• When a melt cools, different minerals freeze at
  different temperatures. The minerals that cool
  at nearly the same temperatures tend to occur
  together in rocks.
• Only certain minerals can occur together.

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Bowens Reaction series

• Continuous series - Ca-Na Plagioclase
• Discontinuous series - Olivine, Pyroxenes,
  Amphiboles, Biotite
• Felsic Minerals - K-spar, Muscovite, Quartz

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Rock Names

• Granite / Rhyolite - from felsic magmas
• Diorite / Andesite - intermediate
• Gabbro / Basalt - mafic
• Peridotite -- ultramafic

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Igneous Textures

• Aphanitic - fine grain
• Phaneritic - coarse grain (visible minerals)
• Porphyritic - both fine and coarse minerals
• Pyroclastic or Fragmental - formed by explosive
  volcanic activity
• Glass --obsidian

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Differentiation of Magma

• Crystal Settling
• Assimilation
• Partial Melting
• Magma Mixing

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Igneous Rocks

• Igneous Rocks
• Formation
• Description
• Classification

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Group Exercise

• Igneous Rocks
• Formation
• Descriptions
• Classification
• Igneous Intrusions
• Intrusive Bodies
• Intrusive Processes

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Recent Events

• Volcanic eruptions in the Congo
• Mount Nyiragongo

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Individual Exercise

• Find an intrusive igneous rock.
• Find one, on Campus, on the eastern end of Trans
  Mountain, at Cristo Rey, or in someones yard.
• Describe its texture. List the visible minerals.
  Bring it to our next class.