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GEO 1121 – Study Guide (1stExam), Fall 2015Intro/ReviewN. Steno – principles of original horizontality, lateral continuity, and superpositionJ. Hutton – principle of uniformitarianism (present is the key to the past)W. Smith – faunal successionC. Lyell – comprehensive Principles of GeologyAlfred Wegener - Formulated the hypothesis that continents are mobile (Continental Drift). Idea was founded on multiple lines of evidence:•“Fit” of continents.•Location of glaciations.•Fossil organisms.•Rock type and structural similarities.•Paleoclimates preserved in rocksAge of Earth is 4.57 Ga based on correlation with…Meteorites.Moon rocksBonding:CovalentElectron sharing e.g. diamondIonicAttraction of two oppositely charged ions e.g. Na+Cl-MetallicOuter shell electrons move freely and bondVan der WaalsPolar bonding b/w molecules e.g. graphiteStates of Matter:Solid - particles (ions, atoms or molecules) are packed closely together. The forces between particles are strong enough so that the particles cannot move freely but can only vibrate. As a result, a solid has a stable, definite shape, and a definite volumeLiquid - nearly incompressible fluid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure. The volume is definite if the temperature andpressure are constantGas - compressible fluid. Not only will a gas conform to the shape of its container but it will also expand to fill the containerPlasma - does not have definite shape or volume, plasmas are electrically conductive, produce magnetic fields and electric currents, and respond strongly to electromagnetic forcesDoppler Effect: sound and light, shift in sound and light waves based on moving sourceEvolving Image of Earth:The ancients thought the Universe was geocentric. Heavenly bodies circle around a motionless central Earth. “Proven” by Ptolemy (100–170 C.E.), the idea was wrong. The idea held as religious dogma for 1,400 years.A heliocentric (sun-centered) universe was proposed by the Greeks ~ 250 B.C.E.Big Bang Theory:Evidenced by ‘red shifts’ of surrounding galaxies observed by Hubble in 1929 lead to expanding Universe theory
Deduction that cataclysmic explosion occurred at a infinitesimally small point around 13.7Ga (billion years)Initial formation of hydrogen atoms (H), with cooling fusion led to helium (He) generation (big bang nucleosynthesis)Further cooling formed molecules e.g. H2 gasCreation of nebulae (initially entirely H and He)The Nebular Theory.A 3rd, 4th or nth generation nebula forms ~4.56 Ga. Hydrogen and Helium left over from the big bang.Heavier elements produced by stellar nucleosynthesis.