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Chapter 1 An Introduction to Geology. What Do You Already Know?. Age of the earth? What causes earthquakes? Any in NY? What causes volcanic activity? Any in NY?. Physical Geology. Examine earth materials Understand earth processes Surface Subsurface. Historical Geology.
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What Do You Already Know? • Age of the earth? • What causes earthquakes? • Any in NY? • What causes volcanic activity? • Any in NY?
Physical Geology • Examine earth materials • Understand earth processes • Surface • Subsurface
Historical Geology • Origin of Earth • Development through time • Fossils • Strata
Environmental Geology • Understand the Earth Systems • Hazards & Resources • Use knowledge to minimize impact and maximize our benefit
Geologic Thought Through HistoryCatastrophism • James Ussher • Mid 1600’s • Earth formed 4004 BC • Rapid violent episodes • The Earth is “Young”
Geologic Thought Through History Uniformitarianism • James Hutton • Late 1700’s • Published “Theory of the Earth” in 1795 • Better understanding of earth processes • “Present is the Key to the Past” • The Earth is “Old”
Geologic TimeRelative Time & Absolute Time • Relative • Determine age of rocks & fossils by their relative location • Absolute • Radioactivity discovered in 1896 • We can analyze the chemistry and assign a specific age to rock or fossil
Fossil Succession • Fossil organisms succeed one another in a specific order (evolution). • Time periods can be recognized by their fossil content
Geologic Time Scale • Eras • Periods • Pre-Cambrian Time • Cambrian Time • Carboniferous Period • Cretaceous Extinction
Universe FormationBig Bang • Supernova ~ 14bya • Slipher & Hubble • Red Shift • Expanding forever?
Solar System FormationNebular Hypothesis • Immanuel Kant ~ 1755 • All elements • Mostly H & He • CCW rotation ~ 5bya • Accretion • ~ 4.6 bya sun turns on
Terrestrial Planets • Smaller • Denser (metallic & rocky) • Closer to the Sun • Why are they smaller & denser?
Jovian Planets • Larger • Less Dense (H2O & CO2) • Further from the sun • Why are they larger & less dense?
Asteroid Belt • Big rocks • Between terrestrial & jovian • Do they hit the Earth? • Why are they there?
Sun • Yellow Dwarf Star (G2) • Mostly H & He • Fusion Bomb • Perihelion • Aphelion • How old is it? • How/when will it die?
Hydrosphere • All Phases of Water • Earth’s surface = 71% ocean • Ocean = 97% of worlds water • Is ocean water potable? • What is happening to sea-level? • Why is it happening?
Atmosphere • Thin Blanket of gases • ~ 10 miles from surface • Formed from volcanic outgassing • Moderates temperature & Protection • Are we changing our atmosphere?
Biosphere • Plants • Animals • All life forms
Geosphere • Lithosphere & everything beneath
The Earth’s Layers • Lithosphere • Asthenosphere • Mantle (Mesosphere) • Outer Core • Inner Core
Continents • Asia • Europe • Africa • Australia • North & South America • Antarctica
Continents • Mountains • Active or “recently” active portions of crust • Cratons • Comprised of Platforms and Shields • Stable or “inactive” portions of the crust
Oceans • Pacific • Atlantic • Arctic • Indian
Oceans • Oceanic ridge system • Prominent topographic feature • Igneous rock • Basalt • Volcanoes