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Geology

Geology. Mineral (definition) naturally occurring, inorganic solid with a specific chemical composition a definite crystalline structure

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Geology

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  1. Geology Mineral (definition) • naturally occurring, • inorganic solid • with a specific chemical composition • a definite crystalline structure • Minerals can form from the cooling of magma which is the molten material found beneath Earth’s surface as magma rises closer to the surface the molten compounds no longer move freely and they begin to interact chemically to form minerals

  2. Geology • Minerals form by combining elements together to create compounds. Each compound is unique and has specific properties that separate it from other compounds • Minerals are like rocks because all rocks are made of minerals

  3. Mineral Properties • Streak is easily determined by rubbing the mineral across an unglazed porcelain plate

  4. Mineral Properties • Streak is used to distinguish pyrite from gold Pyrite Gold

  5. Mineral Properties • Luster is the way a mineral reflects light from its surface and is caused by differences in mineral chemical compositions

  6. Mineral Properties • Either metallic or nonmetallic (dull, pearly, waxy, silky)

  7. Mineral Properties • Texture describes how a mineral feels to the touch • Rough, smooth, ragged, greasy, soapy, glassy

  8. Mineral Properties • Hardness is a measure of how easily a mineral can be scratched and is determined by the arrangement of it’s atoms.

  9. Mineral Properties • The Mohs hardness scale is used to compare a sample to the hardness of ten known minerals

  10. Mineral Properties • Cleavage determines whether a mineral will split easily and evenly along one or more flat planes

  11. Mineral Properties • Mica has perfect cleavage in one direction • Halite has cubic cleavage (3 planes)

  12. Mineral Properties • Fracture means the mineral is tightly bonded and breaks with rough or jagged edges • Quartz has fracture

  13. Mineral Properties • Specific Gravity compares the weight of the mineral to an equal volume of water at 4 degrees C

  14. Mineral Properties • Special Properties such as light reflection and reactions to acids are also useful tools

  15. Mineral Properties • Calcite fizzles when in contact with HCl

  16. Mineral Properties • Calcite also can cause double images

  17. Mineral Properties • Magnetite will attract iron

  18. Mineral Properties • Sulfur produces a rotten egg odor

  19. Geology • Small crystals means the magma cooled rapidly • Large crystals means the magma cooled more slowly

  20. Geology • Silicates are the most abundant group (96%) containing the two most abundant elements in the crust Silicon (Si) and Oxygen (O)

  21. Geology • Quartz and Feldspar are the most abundant minerals found in Earth’s crust

  22. Geology • Carbonates are minerals composed of one or more metallic elements with the carbonate compound CO3 ( 1 atom of carbon and 3 atoms off oxygen)

  23. Geology • Carbonates are the primary minerals in rocks such as limestone, coquina, and marble Limestone Coquina Marble

  24. Uses for Earth Materials • Nearly every single thing we use today comes from Earth directly or indirectly. The following is a list of minerals and ores

  25. Uses for Earth Materials • Name of mineral/ore Use(s) Quartz (mineral) Glass, watches

  26. Uses for Earth Materials Feldspar (mineral) Toothpaste

  27. Uses for Earth Materials • Calcite (mineral) Neutralizing acids

  28. Uses for Earth Materials Mica (mineral) Lampshades, insulation, makeup

  29. Uses for Earth Materials Pyrite (ore) Iron

  30. Uses for Earth Materials • TalcBaby powder

  31. Uses for Earth Materials • Bauxite Aluminum

  32. Virginia’s Important Resources • Coal Energy

  33. Virginia’s Important Resources • Gravel/stone (all) RoadConstruction

  34. Virginia’s Important Resources • Limestone Concrete

  35. Virginia’s Important Resources • Granite Building materials

  36. Virginia’s Important Resources • silica electronics

  37. Virginia’s Important Resources • zirconium & titanium advanced metallurgy

  38. What are Rocks? • A rock is a naturally occurring solid mixture of one or more minerals, or organic matter • Rocks are classified by how they are formed, their composition, and texture • Rocks change over time through the rock cycle

  39. Igneous Rocks • Igneous rock begins as magma. • Magma can form: • When rock is heated • When pressure is released • When rock changes composition • Magma freezes between 700 °C and 1,250 °C • Magma is a mixture of many minerals http://www.fi.edu/fellows/payton/rocks/create/igneous.htm

  40. Igneous Rocks • Felsic: light colored rocks that are rich in elements such as aluminum, potassium, silicon, and sodium • Mafic: dark colored rocks that are rich in calcium, iron, and magnesium, poor in silicon • Coarse-grained: takes longer to cool, giving mineral crystals more time to grow • Fine-grained: cools quickly with little to no crystals

  41. Igneous Rocks Coarse-Grained Fine-Grained Felsic Granite Rhyolite Mafic Gabbro Basalt

  42. Igneous Rocks • Intrusive Igneous Rocks: magma pushes into surrounding rock below the Earth’s surface • Extrusive Rocks: forms when magma erupts onto the Earth’s surface (lava), cools quickly with very small or no crystals formed http://www.windows.ucar.edu/tour/link=/earth/geology/ig_intrusive.html&edu=high&fr=t

  43. Obsidian What is Obsidian? Obsidian is a dark-colored volcanic glass that forms from the very rapid cooling of molten rock material. It cools so rapidly that crystals do not form. Igneous Rocks Obsidian is a dark-colored volcanic glass that forms from the very rapid cooling of molten rock material. It cools so rapidly that crystals do not form. Is this rock Felsic or Mafic? Is it fine-grained or coarse-grained? Is this rock Intrusive or Extrusive? Mafic, fine grained, extrusive

  44. Sedimentary Rocks • Sedimentary rock is formed by erosion • Sediments are moved from one place to another • Sediments are deposited in layers, with the older ones • on the bottom • The layers become compacted and cemented together http://www.fi.edu/fellows/payton/rocks/create/sediment.htm

  45. Sedimentary Rock • Sedimentary Rocks are formed at or near the Earth’s surface • No heat and pressure involved • Strata – layers of rock • Stratification – the process in which sedimentary rocks are arranged in layers

  46. Sedimentary Rock Clastic – made of fragments of rock cemented together with calcite or quartz Breccia is a term most often used for clastic sedimentary rocks that are composed of large angular fragments (over two millimeters in diameter). The spaces between the large angular fragments can be filled with a matrix of smaller particles or a mineral cement that binds the rock together.

  47. Sedimentary Rock Chemical sedimentary – minerals crystallize out of solution to become rock Rock Saltis a chemical sedimentary rock that forms from the evaporation of ocean or saline lake waters. It is also known by the mineral name "halite". It is rarely found at Earth's surface, except in areas of very arid climate. It is often mined for use in the chemical industry or for use as a winter highway treatment. Some halite is processed for use as a seasoning for food. The specimen shown above is about two inches (five centimeters) across.

  48. Sedimentary Rock Organic sedimentary – remains of plants and animals Limestone is a sedimentary rock composed primarily of calcium carbonate (CaCO3) in the form of the mineral calcite. It most commonly forms in clear, warm, shallow marine waters. It is usually an organic sedimentary rock that forms from the accumulation of shell, coral, algal and fecal debris.

  49. Sedimentary Rock Organic sedimentary – remains of plants and animals Coal is an organic sedimentary rock that forms from the accumulation and preservation of plant materials, usually in a swamp environment.  Coal is a combustible rock and along with oil and natural gas it is one of the three most important fossil fuels. 

  50. Metamorphic Rock • Meaning to change shape • Changes with temperature • and pressure, but remains • solid • Usually takes place deep in • the Earth http://www.fi.edu/fellows/payton/rocks/create/metamorph.htm

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