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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.

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Presentation on theme: "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."— Presentation transcript:

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 All igneous rocks cool and crystallize from magma or lava cool and crystallize from magma or lava or consolidate from pyroclastic materials or consolidate from pyroclastic materials Magma is molten material below the surface Magma is molten material below the surface Lava is molten material on the surface Lava is molten material on the surface Pyroclastic materials are particles such as volcanic ash 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 … 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! No melting! Photo by J.P. Lockwood. Figure 24-B, U.S. Geological Survey Bulletin 1595.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

6 What is the Rock Cycle?

7 From USGS at

8 Igneous Part of the Rock Cycle From USGS at

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

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

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

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

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

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

15 Identifying Igneous Rocks Step 2. 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 Texture and composition are the criteria used to classify most igneous rocks Composition categories are based on silica content Composition categories are based on silica content felsic (>65% silica) felsic (>65% silica) intermediate (53-65% silica) intermediate (53-65% silica) mafic (45-52% silica) mafic (45-52% silica)

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

18 Identifying Igneous Rocks Step 4. 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 A Classification of Igneous Rocks Cooling History / Texture Slow Cooling and Coarse Grained Fast Cooling and Fine Grained Very Fast Cooling and Glassy/Cellular Mafic and Dark Color GabbroBasalt Scoria Intermediate in composition and color DioriteAndesite Felsic and Light Color GraniteRhyolitePumice and Obsidian

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

22 Volcanoes! Image from Lassen Volcanic National Park, CA

23 Volcanic Deposits Shape depends on composition of magma… Basaltic Andesitic Rhyolitic …and gas content … and number and size of eruptions … and the environment of eruption

24 Volcanic Deposits

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

26 Basaltic Lava High temperature ( C) High temperature ( C) Lower silica content Lower silica content Extremely fluid Extremely fluid Images courtesy of Alison Henning, Rice University

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

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

29 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

30 Volcanic Landforms Shield volcanoes – Mauna Loa Shield volcanoes – Mauna Loa Big Big Broad, Low Slope Broad, Low Slope Properties of lava? Number of flows? Types of rocks? Properties of lava? Number of flows? Types of rocks? Image from

31 Volcanic Landforms Lava Plateau Lava Plateau Extensive Extensive Stacked flows Stacked flows Virtually no slope Virtually no slope Properties of lava? Number of flows? Type of rock? Properties of lava? Number of flows? Type of rock? Photo from

32 Columbia Plateau 130,000 Km2 x 1.5 km thick Buried topography ~16 Ma

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

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

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

36 Composite Volcano - Mt St Helens Images from

37 Pinatubo USGS photo by Dave Harlow

38 Volcanic Landform Dome Dome Small Small Steep slope Steep slope Properties of lava? Number of flows? Type of rock? Properties of lava? Number of flows? Type of rock?

39 Foreshadowing … Patterns to where types of volcanos occur?

40 If a planet has active volcanos, what do we know about the planet? NASA/JPL/NGA image from

41 Where Does the Heat Come From? Hubble Image from

42 Where Does the Heat Come From? (Terrestrial Planets) Originally: Impacts (accretion), differentiation, radioactive decay Presently: Mostly radioactive decay Image by LPI: Image by LPI

43 What Evidence Suggests Volcanism on Other Planets? NASA image at

44 What Planets Are / Have Been Volcanically Active? Past Mercury, Venus, Earth, Moon, Mars, Io, Titan Presently Earth, Io, Enceledus, Triton Probably Venus and Mars Photo montage from

45 Why Might a Planet Have Ceased Being Volcanically Active? Image: Lunar and Planetary Laboratory:

46 Our Moon What do you observe? Image at

47 Big Impact Basins Filled by Lava Apollo image from Mare Imbrium Volcanism after impacts – most before 3 Ga (to 1 Ga)

48 Fissure Eruption Courtesy of USGS.

49 Lunar Basalts Billion Years Old Apollo image at Apollo image from

50 Lunar Volcanism Aristarchus Plateau Marius Hills photo by Lunar Orbiter V at Photo of Aristarchus Plateau at

51 Mercury Tons of Craters Some Flat Plains … hmmmmmm… Only ~ 1/3 imaged Messenger spacecraft on its way to orbit! Image:

52 Craters and Plains 500 km Mariner image at

53 Venus Magellan image from

54 Venera Images Image:

55 Sapas Mons – 1.5 km high, 400 km across Atla Regio Magellan image at

56 Maat Mons – 8 km high, Aphrodite Terra Region Magellan color image at Courtesy of David P. Anderson (Southern Methodist University) Image at

57 Pancake Domes Single Flows, Steep sides Height 1/2 - 1 km. What kind of volcano? What kind of lava? NASA Image from LPI:

58 Pancake Domes Rhyolite? Or merely cold, crystal-rich basalt? What kind of volcano? What kind of lava? USGS photo by R.A. Bailey

59 What’s missing? Few impact craters – what does this tell us? No craters less than 3 km (meteoroid ~ 30 m across) Atmospheric filter Magellan image from

60 Mars dfldjfkdkfj dfldjfkdkfj MOLA image from

61 Volcanoes on Mars Mars geologic map at

62 Mars meteorite image at

63 Olympus Mons TALLEST Volcano in the Solar System 24 km high km across Mauna Loa 9 km high (sea floor) 120 km across (base) Lava flows in last million years? Viking image at

64 Mars LPI image at

65 LPI image at

66 Mars Olympus Mons Image overlain on topography and vertically exaggerated 10x MOLA image at

67 Mars Express images from And

68 Broken Cinder Cone? On Syrtis Major - Shield Volcano USGS image at Themis image at

69 Why Might a Planet Have Ceased Being Volcanically Active?

70 Hubble

71 Io NASA Gallileo Image at:

72 Io About the size of our Noon HOT – tidal friction Lots of Sulfur Voyager detected Yellow-brown color Silicate lava – crust is silicate in nature (strong; supports high mountains and deep crevasses; lava flows at temps too high for S) NASA Gallileo Image at:

73 Io Galileo Image Tvashtar Catena NASA Galileo image at:

74 Io Amirani Lava Flow – Galileo Image Largest active flow in solar system (~ km) Galileo image from

75 Plumes of sulfur / sulfur dioxide Long-lived (months) Geysers High – lack of atmospheric pressure and low gravity Old Faithful – 35 km high if on Io Io Voyager image at

76 New Horizons flew past Io in late February 2007 New Horizons photos at lhttp://pluto.jhuapl.edu/gallery/missionPhotos/pages/022707_1.htm


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