3 MAIN ROCK TYPES: IGNEOUS , SEDIMENTARY , & METAMORPHIC IGNEOUS - COOLS FROM MOLTEN ROCK

1. 3 MAIN ROCK TYPES: IGNEOUS, SEDIMENTARY, & METAMORPHIC IGNEOUS- COOLS FROM MOLTEN ROCK SEDIMENTARY- RECOMBINED FRAGMENTS OF MINERALS, ROCKS, &/OR ORGANIC ORIGIN METAMORPHIC- PRE-EXISTING ROCKS CHANGED IN COMPOSITION, MINERALOGY, OR TEXTURE FROM HIGH TEMPERATURES, PRESSURES, &/OR FLUIDS THE ROCK CYCLE - CONSTANT REWORKING OF ROCKS IN THE EARTH'S INTERIOR & AT SURFACE BY DEFORMATION, WEATHERING, EROSION, ETC... TO FORM NEW ROCKS

2. Phase (Pressure-Temperature) Diagram for Lithospheric & Asthenospheric Depths Most regions of the outer 200 km of the earth DO NOT have melt! TEMPERATURE VS DEPTH (GEOTHERM) Davidson 4.2

3. IGNEOUS ROCKS SILICATE MATERIAL (WITH GASSES) MELTS AT DEPTH MELTED MAGMA LESS DENSE THAN SURROUNDING SOLID SO RISES INTRUSIVE ROCK: SOLIDIFIES ("CRYSTALLIZES”/"FREEZES") AT DEPTH EXTRUSIVE ROCK: LAVA ERUPTS AT SURFACE & FORMS. COOLING LAVA RELEASES GASSES INTO ATMOSPHERE IGNEOUS ROCKS CLASSIFIED BY THEIR CHEMICAL COMPOSITION (HOW MUCH SiO2 ), MINERALS, AND INTRUSIVE OR EXTRUSIVE “every rock and tree and creature has a life, has a spirit, has a name…”

4. MORE DENSE LESS DENSE IGNEOUS ROCKS classified by chemical composition & cooling rate Felsic- more FELdspar and SIlica Mafic- more Magnesium and iron (Fe) ----------------------Texture reflects cooling: Extrusive/Fine Grain Intrusive/Coarse Grain LESS SiO2 SiO2 (Mg,Fe)2SiO4 Davidson 4.4

5. THREE IMPORTANT PAIRS OF IGNEOUS ROCKS RHYOLITE / GRANITE (>63% SiO2): MOST OF CONTINENTAL CRUST, DENSITY ABOUT 2.8 g/cm3 , FORMS BY MELTING CONTINENTAL CRUST ANDESITE */ DIORITE (63-52% SiO2) FROM MELTING OCEANIC CRUST, OFTEN AT SUBDUCTION ZONES BASALT / GABBRO (<52% SiO2) MOST OF OCEANIC CRUST, DENSITY ABOUT 3.3 g/cm3, FROM MELTING MANTLE, OFTEN AT MIDOCEAN RIDGES BECAUSE GRANITE IS LESS DENSE THAN BASALT: CONTINENTS "FLOAT" HIGHER THAN THE OCEAN CRUSTSO WE LIVE ABOVE SEA LEVEL CONTINENTS NEVER SUBDUCT BACK INTO THE MANTLE SO FORMED EARLY IN EARTH HISTORY & ARE OLD (LESS THAN 500 MYR TO 4 BYR), COMPARED TO OCEANIC CRUST THAT SUBDUCTS SO IS YOUNG (0-200 MYR) *LIKE ANDES

6. Igneous rock textures formed primarily by cooling rate MICROSCOPE IMAGE LARGE GRAINS SMALL GRAINS LARGE & SMALL GRAINS Davidson 4.4

7. SINGLE CRYSTAL GROWING FOR INTEGRATED CIRCUIT (IC or MICROCHIP) PRODUCTION ICs are built on single-crystal silicon substrates of high purity and perfection. Single-crystal silicon is used instead of polycrystalline silicon since the former does not have defects associated with grain boundaries. - Silicon inside the chamber is melted (Si melts at 1421 deg C). -  A slim seed of crystal silicon (5 mm dia. and 100-300 mm long) is introduced into the molten silicon. -  The seed crystal is withdrawn at a very controlled rate, and grows. - Wafers are sliced off the crystal  and circuits built on them

8. FRACTIONAL CRYSTALIZATION /PARTIAL MELTING AS MAGMA COOLS SOLID MINERALS THAT "FREEZE" OUT DIFFER IN COMPOSITION FROM REMAINING LIQUID AS MAGMA COOLS MINERALS FORM DEPEND ON TEMPERATURE ("FRACTIONAL CRYSTALIZATION") REVERSE PROCESS OCCURS DURING MELTING ("PARTIAL MELTING") PROCESS ILLUSTRATED WITH HALF-FROZEN APPLE JUICE

9. CRYSTALLIZATION OF MAGMA AS TEMPERATURE DROPS CRYSTALS SINK TO BOTTOM SiO2-POOR MINERALS FREEZE OUT MAGMA BECOMES MORE SiO2-RICH Evanston’s population “ages” over summer break Davidson 4.6

10. http://science.howstuffworks.com/oil-refining2.htm

11. MAGMA VISCOSITY- VOLCANIC ERUPTION CHARACTERISTICS LARGELY CONTROLLED BY THE VISCOSITY - "GOOEYNESS" (RESISTANCE TO FLOW) - OF THE MAGMA: LOW VISCOSITY FLUIDS FLOW MORE EASILY THAN HIGH VISCOSITY FLUIDS Higher temperature, lower viscosity (warm syrup flows more easily than cold) Viscosity increases with increasing silica content due to silica chains High viscosity lavas flow slowly and typically coversmall areas. Low viscosity magmas flow more rapidly and cover thousands of square km. Low viscosity magmas allow gases to escape easily. Gas pressures can build up in high viscosity magmas - so violent eruptions (Blowing through a straw, it's easier to get water to bubble than a milk shake)

12. High viscosity magma- SiO2 rich Low viscosity magma- low SiO2

13. MAGMA VISCOSITY & VOLCANO TYPE High viscosity lava flow slowly & typically cover small areas, forming composite volcanoes (stratovolcanoes) (e.g. Mt. St. Helens) that explode violently due to trapped gas Low viscosity lavas flow rapidly & form shield volcanoes (e.g. Hawaii) with flows covering thousands of square kilometers

14. Mount Saint Helens- stratovolcano (composite volcano) with viscous dacitic (SiO2-rich) magma containing lots of dissolved gas (mostly water vapor), before 1980 explosive eruption, after, & today AFTER BEFORE JANUARY 2005- NEW ASH & DOME FORMING IN CALDERA

15. Successive stages of development of Crater Lake, Oregon Davidson 4.15

16. 2002 ERUPTION: BIG ISLAND OF HAWAII Brian White (CAS 2000) Seth Stein

17. http://hvo.wr.usgs.gov/cam/index.htm

18. Different types of volcanoes at different tectonic settings Japan, Aleutians East African Rift St Helens, Andes Davidson 4.16

19. The two main ways in which melting occurs in the mantle SOLIDUS - MELTING CURVE GEOTHERM - TEMPERATURE vs DEPTH MIDOCEAN RIDGE SUBDUCTION ZONE WATER LOWERS MELTING TEMPERATURE MELTING AT LOWER PRESSURE

20. ACTIVE VOLCANOES CONCENTRATED AT PLATE BOUNDARIES

21. MARS: Olympus Mons Stands 27 kilometres (88,600 feet) high over its base (about three times the height of Everest above sea level) Caldera is 85 km (53 miles) long, 60 km (37 miles) wide, and up to 3 km (1.8 miles) deep with six overlapping pit craters. Outer edge is defined by an escarpment up to 6 km (4 miles) tall unique among the shield volcanoes of Mars. Olympus Mons is roughly the size of the state of Missouri

22. What type of volcano is Mt. Doom (Orodruin) in the “Lord of the Rings”?