6Earth and the Universe (external effects) Earths’ Rotation (Day-Night)Lunar Effects (Tides)Annual Variation (Seasons)Precession and Orbit Variations (Ice Ages?)Galactic Rotation (250 m.y. period)Unpredictable EventsNearby SupernovaeMeteor ImpactsLong-Term Evolution of Sun
7Atmospheric Circulation Unequal Solar HeatingEquator to PoleDay - NightDifferent SurfacesBuoyancyHeating and CoolingCoriolis EffectHigh and Low Air PressuresFronts and Air Masses
8Oceanic Circulation Surface Currents - Driven by Winds Thermohaline - Deep CirculationEvaporation makes water more saline and denserFreezing makes water more saline and denserCold water is denser than warm water
13Water Principal Agent in Modifying Earth’s Surface Medium for Storing and Distributing Global HeatThe Universal SolventEssential for LifeDestructive to RocksLowers Melting Point of RocksReduces Strength of Rocks Under Pressure
14The Rock Cycle New Rocks Exposed by Erosion Rocks Broken Down Mechanically and Chemically (Weathering)Components Transported by ErosionComponents Cemented into Sedimentary RocksBurial and Heating creates Metamorphic RocksMelting Creates Igneous Rocks
19Configuration of Continents Oceanic CirculationWeather and Climate PatternsDesertsMountains and Rain ShadowsPathways for MigrationEcological Niches
20Some Unique Aspects of Geology Importance of RelationshipsSequentialSpatialImportance of TimeDistinctive Problems of EvidenceSlow RatesRare EventsDestruction of EvidenceInaccessibility
21Some Geologic Rates Cutting of Grand Canyon 2 km/3 m.y. = 1 cm/15 yr Uplift of Alps5 km/10 m.y. = 1 cm/20 yr.Opening of Atlantic5000 km/180 m.y. = 2.8 cm/yr.Uplift of White Mtns. (N.H.) Granites8 km/150 m.y. = 1 cm/190 yr.
22Some Geologic Rates Movement of San Andreas Fault 5 cm/yr = 7 m/140 yr.Growth of Mt. St. Helens3 km/30,000 yr = 10 cm/yr.Deposition of Niagara Dolomite100 m/ 1 m.y.? = 1 cm/100 yr.
231 Second = 1 Year 35 minutes to birth of Christ 1 hour+ to pyramids 3 hours to retreat of glaciers from Wisconsin12 days = 1 million years2 years to extinction of dinosaurs14 years to age of Niagara Escarpment31 years = 1 billion years
24Some Unique Aspects of Geology (Continued) Reliance on Inference and DeductionIntrinsically "Unsolvable" ProblemsAncient LandscapesMass ExtinctionsAncient Ocean Basins
25Scientific Principles in Geology Parsimony (Keep It Simple)SuperpositionUniformitarianismUsing these, plus observation, we establish facts about Earth Processes
26Parsimony The simplest explanation that fits all the data is preferred Doesn’t guarantee that things must be simple!Theories with lots of ad hoc or unsupported ideas are probably wrong.