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The Fire Within: Plate Tectonics & Volcanism Across the Solar System By the Lunar and Planetary Institute For Use In

The Fire Within: Plate Tectonics & Volcanism Across the Solar System By the Lunar and Planetary Institute For Use In Teacher Workshops. USGS Photo by B. Chouet. What’s a Rock? What are the Main Rock Types? How Do They Form? How Do You Tell One from Another?. Igneous. All igneous rocks

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The Fire Within: Plate Tectonics & Volcanism Across the Solar System By the Lunar and Planetary Institute For Use In

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  1. The Fire Within: Plate Tectonics & Volcanism Across the Solar System By the Lunar and Planetary Institute For Use In Teacher Workshops USGS Photo by B. Chouet

  2. What’s a Rock?What are the Main Rock Types?How Do They Form?How Do You Tell One from Another?

  3. Igneous • All igneous rocks • cool and crystallize from magma or lava • or consolidate from pyroclastic materials • Magma is molten material below the surface • Lava is molten material on the surface • Pyroclastic materials are particles such as volcanic ash

  4. Metamorphic • Changes in minerals, texture, and/or chemical composition of a rock that result from changes in temperature and pressure … like burial, contact with hot stuff, extreme crunching … • No melting! Photo by J.P. Lockwood. Figure 24-B, U.S. Geological Survey Bulletin 1595.

  5. Clastic Sedimentary Rocks Sediment particles (skeletal, rock fragment, mineral, plant particles) derived from erosion (breakdown / transport) of rock that are lithified (cemented or compacted) Carbonate / Other Sedimentary Rocks Chemical precipitates (halite) or biologically - produced (organic) material (shell fragments). In-situ. Sedimentary Images from http://wrgis.wr.usgs.gov/parks/rxmin/rock2.html

  6. What is the Rock Cycle?

  7. From USGS at http://3dparks.wr.usgs.gov/nyc/images/fig6.jpg

  8. Igneous Part of the Rock Cycle From USGS at http://3dparks.wr.usgs.gov/nyc/images/fig6.jpg

  9. Igneous Rocks • All igneous rocks • cool and crystallize from magma or lava • or consolidate from pyroclastic materials • Magma is molten material below the surface • Lava is molten material on the surface • Pyroclastic materials are particles such as volcanic ash

  10. Identifying Igneous Rocks • Step 1. Is it an igneous rock? Interlocking randomly oriented crystals? Published as figure 14 in U.S. Geological Survey. Bulletin 1595. 1987

  11. Identifying Igneous Rocks • Extrusive or volcanic rocks • form at the surface from lava or pyroclastic materials • Intrusive or plutonic rocks • form from magma in the crust

  12. Identifying Igneous Rocks • Igneous rocks have 4 textures • determined by the cooling rate of magma or lava • Texture • size, shape and arrangement of crystals in a rock

  13. 4 Cooling-Rate Textures • Phaneritic – Coarse Grained (Intrusive) • visible grains, cooled slowly • Aphanitic – Fine Grained (Extrusive) • with grains too small to see, cooled quickly • Porphyritic – (Extrusive) • with larger grains surrounded by a finer-grained groundmass • cooled slowly first, then more quickly • Glassy • with no grains • cooled too quickly for minerals to grow

  14. Igneous Rock Textures • Also vesicular texture, with holes (vesicles) • indicates the rock formed as water vapor and other gases became trapped during cooling of lava • Pyroclasticor fragmental texture • containing fragments formed by consolidation of volcanic ash or other pyroclastic material

  15. Identifying Igneous Rocks • Step 2. Coarse grained or fine grained? (Porphyritic or Aphanitic) From the USGS photo glossary of volcanic terms

  16. Igneous Rocks • Texture and composition are the criteria used to classify most igneous rocks • Composition categories are based on silica content • felsic (>65% silica) • intermediate (53-65% silica) • mafic (45-52% silica)

  17. Identifying Igneous Rocks • Step 3. Light or Dark? … Composition Hints Images from USGS Photo Library

  18. Identifying Igneous Rocks • Step 4. What minerals present? Quartz – gray opaque, concoidal fracture K-Spar - pink Plagioclase feldspar – white to gray Muscovite – light, flakey Biotite – dark, flakey Pyroxene - LBM Amphibole - LBM USGS Mineral Specimen Photography: Bureau of Mines, ___ and Mineral collection of Bringham Young University Department of Geology, Provo, Utah

  19. Igneous Rock Classification Diagram by staff of LPI

  20. Green sand beach – why green? Image courtesy of Alison Henning, Rice University

  21. Lassen Volcanic National Park, CA Volcanoes! Image from http://photo.itc.nps.gov/storage/images/lavo/lavo-Full.00005.html

  22. Shape depends on composition of magma… Basaltic Andesitic Rhyolitic Volcanic Deposits …and gas content … and number and size of eruptions … and the environment of eruption http://volcanoes.usgs.gov/Hazards/What/hazards.html

  23. Volcanic Deposits http://volcanoes.usgs.gov/Products/Pglossary/basalt.html

  24. Why does silica matter? • Si - O bonds much stronger than others • In lava, single silica tetrahedra flow easily, like little balls • In lava, large silicate polymers flow poorly, like noodles Diagram by staff of LPI

  25. Basaltic Lava • High temperature (1000-1200 C) • Lower silica content • Extremely fluid Images courtesy of Alison Henning, Rice University

  26. Basaltic Lava • Flood basalts – huge plateaus (e.g. Columbia Plateau of Washington and Oregon) • Pahoehoe and aa – ropy vs. jagged blocks (e.g. Hawaiian volcanoes) • Pillow lavas – ellipsoidal, cool underwater Images from USGS Photo Glossary of Volcano Terms

  27. Rhyolitic Lava • Most felsic, light in color • Higher silica content • Lower melting point than basalt. Erupts at 800-1000 C • Moves 10 X more slowly than basalt • Tends to be explosive – more gas (water) content USGS Photo Glossary of Volcano Terms

  28. Gas Content • Magma rises close to surface, pressure drops • Volatiles released with explosive force • Explosive eruptions most likely with gas-rich, viscous rhyolitic and andesitic magmas • Pyroclasts – rock material ejected into air Image courtesy of Alison Henning, Rice University

  29. Volcanic Landforms • Shield volcanoes – Mauna Loa • Big • Broad, Low Slope • Properties of lava? Number of flows? Types of rocks? Image from http://hvo.wr.usgs.gov/maunaloa/

  30. Volcanic Landforms • Lava Plateau • Extensive • Stacked flows • Virtually no slope • Properties of lava? Number of flows? Type of rock? Photo from http://en.wikipedia.org/wiki/Image:3-Devils-grade-Moses-Coulee-Cattle-Feed-Lot-PB110016.JPG

  31. Columbia Plateau • 130,000 Km2 x 1.5 km thick • Buried topography • ~16 Ma

  32. Volcanic Landforms • Cinder Cones • Small • Steep slope (30o) • Basaltic … hmmmm • Properties of lava? Number of flows? Types of rocks? USGS Photo by K. Segerstrom USGS image NPS image from Capulin, NM

  33. Small • Few events • Flanks of Mauna Kea • Common on shield volcano flanks USGS Photo Glossary of Volcano Terms

  34. Volcanic Landforms • Composite Volcano • Big • High slope (30o) • Made of multiple lava and ash flows • Explosive USGS Photo Glossary of Volcano Terms • Properties of lava? Number of flows? Types of rocks?

  35. Composite Volcano - Mt St Helens Images from http://vulcan.wr.usgs.gov/Volcanoes/MSH/SlideSet/ljt_slideset.html

  36. Pinatubo USGS photo by Dave Harlow

  37. Volcanic Landform • Dome • Small • Steep slope • Properties of lava? Number of flows? Type of rock?

  38. Foreshadowing … Patterns to where types of volcanos occur?

  39. If a planet has active volcanos, what do we know about the planet? NASA/JPL/NGA image from http://photojournal.jpl.nasa.gov/catalog/PIA06668

  40. Where Does the Heat Come From? Hubble Image from http://hubblesite.org/newscenter/archive/releases/1998/38/image/a/

  41. Where Does the Heat Come From?(Terrestrial Planets) Originally: • Impacts (accretion), differentiation, radioactive decay Presently: • Mostly radioactive decay Image by LPI Image by LPI: http://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=168

  42. What Evidence Suggests Volcanism on Other Planets? NASA image at http://photojournal.jpl.nasa.gov/catalog/pia00254

  43. Past • Mercury, Venus, Earth, Moon, Mars, Io, Titan • Presently • Earth, Io, Enceledus, Triton • Probably Venus and Mars Photo montage from http://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=2167 What Planets Are / Have Been Volcanically Active?

  44. Image: Lunar and Planetary Laboratory: http://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=178 Why Might a Planet Have Ceased Being Volcanically Active?

  45. Our Moon What do you observe? Image at http://www.lpi.usra.edu/education/timeline/gallery/slide_61.html

  46. Big Impact Basins Filled by Lava Apollo image from http://www.lpi.usra.edu/expmoon/Apollo15/A15_Photography_orbital.html Mare Imbrium Volcanism after impacts – most before 3 Ga (to 1 Ga)

  47. Fissure Eruption Courtesy of USGS. http://www.geology.sdsu.edu/how_volcanoes_work/Thumblinks/Puuoorift_page.html

  48. Lunar Basalts 15555 Apollo image from http://curator.jsc.nasa.gov/lunar/compendium.cfm 3.3 Billion Years Old 15016 Apollo image at http://www.lpi.usra.edu/expmoon/Apollo15/A15_BasaltFS.gif

  49. Lunar Volcanism Aristarchus Plateau Photo of Aristarchus Plateau at http://lunar.gsfc.nasa.gov/images/gallery/2Craters_br-browse.jpg Marius Hills photo by Lunar Orbiter V at http://history.nasa.gov/SP-168/section2b.htm

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