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Rocks

2002 Minerals Education Workshop Sponsored by: Indiana Department of Natural Resources – Division of Reclamation November 1-2, 2002. Rocks. www.caingram.com. Rocks. A rock is an aggregate of one or more minerals. http://people.uncw.edu. Rocks. Divided into 3 main groups based on origin:.

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Rocks

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  1. 2002 Minerals Education WorkshopSponsored by:Indiana Department of Natural Resources – Division of ReclamationNovember 1-2, 2002

  2. Rocks www.caingram.com

  3. Rocks A rock is an aggregate of one or more minerals. http://people.uncw.edu

  4. Rocks Divided into 3 main groups based on origin: Igneous Sedimentary Metamorphic www.travelwest.net

  5. Form as a result of cooling & crystallization of magma & lava Indiana Geological Survey “Fire” Igneous Rocks –

  6. Igneous Rocks www.eos.duke.edu • Parent rocks for all other rocks • 65% of the Earth’s crust • Two major classifications: extrusive and intrusive

  7. Volcanic (extrusive) rocks: www.mineralminers.com www.mineralminers.com www.geo.aau.dk Igneous Rocks Classified as either: Crystallize quickly in volcanic eruptions  very small or no crystals

  8. Granite www.geocities.com www.uct.ac.za Igneous Rocks • Plutonic (intrusive) rocks: Crystallize slowly within the earth that allows crystals to grow

  9. http://kafossils.tripod.com

  10. e x t r u s i v e Granite Diorite Kimberlite Gabbro http://volcanoes.usgs.gov Basalt Rhyolite i n t r u s i v e Pumice Obsidian http://cwx.prenhall.com http://cwx.prenhall.com Common Igneous Rocks

  11. Identifying Igneous Rocks • Identification is based on texture (overall appearance of the rock – size, shape & arrangement of mineral grains) and mineralogical composition • Interlocking mineral crystals

  12. ROCK TEXTURE IGNEOUS Crystalline (interlocking) www.env.duke.edu Modified from Indiana Geological Survey

  13. Phaneritic texture: coarse-grained; mineral grains are macroscopic www.uct.ac.za Identifying Igneous Rocks • Texture indicates the rate of cooling

  14. Identifying Igneous Rocks • Aphanitic texture: fine-grained; mineral grains are microscopic http://volcanoes.usgs.gov

  15. Identifying Igneous Rocks • Glassy texture www.mineralminers.com www.mineralminers.com

  16. Identifying Igneous Rocks • Porphyritic texture: contains at least (2) different grain sizes www.uct.ca.za

  17. Identifying Igneous Rocks • Vesicular texture: numerous cavities http://volcanoes.usgs.gov

  18. Identifying Igneous Rocks • Pyroclastic http://volcanoes.usgs.gov

  19. Identifying Igneous Rocks • Identification is based on texture (overall appearance of the rock – size, shape & arrangement of mineral grains) and mineralogical composition

  20. Sedimentary Rocks www.geo.cornell.edu

  21. Sedimentary Rocks • Form from weathered igneous, sedimentary and/or metamorphic rocks • Weathered fragments • transported by water, • air or ice • Can also form from • chemical processes http://earthsci.org

  22. Sedimentary Rocks Indiana Geological Survey

  23. Sedimentary Rocks Indiana Geological Survey

  24. Indiana Geological Survey

  25. Sedimentary Rocks • Generally layered • or bedded www.geo.cornell.edu

  26. Evaporite deposits (white deposits) Indiana Geological Survey

  27. to coarse grained www.nps.gov www.wps.prenhall.com Sedimentary Rocks • Textures range from • very fine grained

  28. www.uky.edu www.kyu.edu www.uky.edu Sedimentary Rocks • May contain • fossils

  29. www.geo.cornell.edu

  30. www.palaeos.com www.uky.edu www.geocities.com/atrypa www.uky.edu www.geocities.com www.uky.edu

  31. Detrital sedimentary rocks: composed of fragmented pre-existing rocks deposited by water, wind or ice and cemented together by minerals precipitated within the void spaces Identifying Sedimentary Rocks • Identification is based on particle size, particle shape, mineral composition and texture e.g. conglomerate/breccia, sandstone, siltstone, shale, mudstone

  32. Generally composed of a combination of quartz, feldspar, rock fragments & clay minerals Identifying Sedimentary Rocks • Identification is based on particle size, particle shape, mineral composition and texture • Detrital sedimentary rocks

  33. Fizz Identifying Sedimentary Rocks • Identification is based on particle size, particle shape, mineral composition and texture • Detrital sedimentary rocks • Chemical sedimentary rocks Identified mostly by mineral composition (e.g. limestone, CaCO3)

  34. Clastic: sedimentary rocks made up of broken particles (all detrital rocks & some chemical sedimentary rocks) www.geo.cornell.edu Identifying Sedimentary Rocks • Clastic and nonclastic texture:

  35. Nonclastic: remaining chemical sedimentary rocks http://earthsci.org www.nps.gov Identifying Sedimentary Rocks • Clastic and nonclastic texture:

  36. ROCK TEXTURE SEDIMENTARY www.eos.duke.edu Fragmental (clastic) Modified from Indiana Geological Survey

  37. Common Sedimentary Rocks • Shale • Limestone wps.prenhall.com • Sandstone www.rockware.com • Conglomerate • Dolomite (Dolostone) • Siltstone • Breccia

  38. Metamorphic Rocks

  39. Metamorphic Rocks (Meta = change morph = form) • Pre-existing rocks are converted to metamorphic rocks by increased temperature, pressure and/or chemical fluids

  40. Rock Cycle Metamorphic Rocks • Derived from pre-existing igneous and sedimentary rocks (e.g. limestone  marble)

  41. http://earthsci.org

  42. http://earthsci.org

  43. Metamorphic Rocks Faulting Folding www.dc.peachnet.edu (Charlie Watson) www.personal.rdg.ac.uk

  44. Foliated (layered) parallel layers of minerals www.geolsoc.org.uk Non-foliated: no preferred orientation of minerals www.eos.duke.edu Metamorphic Rocks • Fine-grained to coarse-grained • Generally classified according to texture

  45. ROCK TEXTURES METAMORPHIC SEDIMENTARY IGNEOUS www.eos.duke.edu Foliated (banded) Crystalline (interlocking) Fragmental (clastic) Indiana Geological Survey

  46. http://geology.csupomona.edu Metamorphic Rocks • Foliated (layers) metamorphic rock textures: • Rock cleavage: mica crystals become aligned resulting in flat surfaces that are parallel (rock tends to split into flat slabs Increasing Temperature & Pressure

  47. http://geology.csupomona.edu Metamorphic Rocks • Foliated (layers) metamorphic rock textures: • Rock cleavage: mica crystals become aligned resulting in flat surfaces that are parallel (rock tends to split into flat slabs • Schistosity: mica crystals grow larger giving rock a “platy” or scaly look Increasing Temperature & Pressure

  48. Metamorphic Rocks • Foliated (layers) metamorphic rock textures: • Rock cleavage: mica crystals become aligned resulting in flat surfaces that are parallel (rock tends to split into flat slabs • Schistosity: mica crystals grow larger giving rock a “platy” or scaly look Increasing Temperature & Pressure • Banding: light & dark minerals separate giving rock a banded look

  49. Metamorphic Rocks http://geology.csupomona.edu www.geolsoc.org.uk

  50. Metamorphic Rocks • Nonfoliated metamorphic rock texture: http:geology.csupomona.edu

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