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The Fire Within: Plate Tectonics & Volcanism Across the Solar System

This informative guide explores the different types of rocks, including igneous, metamorphic, and sedimentary rocks. Learn how they form, identify them based on their textures and compositions, and understand the role of volcanism in the rock cycle. Presented by the Lunar and Planetary Institute for use in teacher workshops.

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The Fire Within: Plate Tectonics & Volcanism Across the Solar System

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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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