Exam-III Review (2014) (24% of total grade)
Geochem/Habitable Planet EESC 3101
Topics from lectures 16-22 (= 70% of Final)
As always, focus will be on material covered in
lectures, as reinforced by readings.
Rock Weathering
Weathering agents, soil acid, congruent v. incongruent, dissolution, adsorption, hydrolysis; Redox
weathering, Granite weathering; examples from feldspar-clay
Mineral susceptibility; mineral
stability diagrams
Rain, Oceans
Eh, pH, TDS -- factors and variations in rain, rivers and seawater
Rain – acidity, composition, spatial variations
Seawater comp'n – pH, carbonate speciation, ions, conservative, residence time Sr and Nd isotope
variations and sources
Biological processes: production, nutrients, upwelling, cycling,
Secretions: carbonate & opal shells, CCD; volcanic and detrital-seawater reactions
Stable Isotopes, Climate Change and Proxies
Long-term: C reservoirs on earth (relative size), carbonate and silicate weathering reactions;
Sr isotopes
Tectonic forcing; effects on weathering and CO2; ice ages; Milankovitch
Oxygen isotopes – mass dependent fractionation, oscillator model and bonds Oxygen
paleothermometer – alpha, delta, temperature dependence of cc-water
Kinetic fractionation of O isotopes between ocean, atm, rain and ice, latitude
Glacial oscillations, T v. ice volume; ice mass balance; long-term effects
Mg/Ca thermometer;
Cenozoic record.
Noble gas thermometer in groundwater CO2-T feedback
Organic Chemistry & Fossil Fuels & Ores
Molecules of life: proteins, carbs, lipids, lignins (plants v. animals)
Carbon cycle: atm, hydro, bio, lithosphere exchanges
Carbon isotope fractionation – carbonate v. organic carbon v. mantle;
Cenozoic C isotope record;
abrupt events
Evidence for early life: stromatolites, fossil microbes, Archean organic carbon Origin of life from
organic elements, catalysts, clay, substrates, meteorites
Coal: land plants, peat, lignite, bituminous, anthracite, Cretaceous, Carb-Perm Lignins, humic
kerogen, high C/H metamorphism, aliphatic, aromatic, vitrinite
Oil: sapropelic kerogen, marine shales, P-T window, lipids & proteins, v. coal
Efficiency of burning methane v. hexane v. coal: bond strength
Comprehensive Aspects ( = 30 % of Final)
Review previous exams and problems sets
Common Themes:
• Mass balance & mixing, feedbacks, steady-state, decay, K, D, alpha
• REE, using melting/crystallization equations, creation of elements, link to Sm-Nd isotopes
• Geochemical constraints on chronology (solar system, earth, core, continent, climate)
• Concentration of elements in reservoirs (stars, chond., core, mantle, crust, ocean, atm) – e.g., pie
charts; review siderophile, etc.; make a list of minerals, isotopes discussed in class
• Trace an element from the big bang, to your body, through all necessary geological reservoirs
(including minerals and solid earth!)
• Critical environments -- black smokers, carbonates, subduction zones, early Earth
• Make your own review page, sketching relevant diagrams/plots from lectures
(e.g., O, C and Sr
isotope isotope marine record; effect of partial melting on an incompatible element; concordia; river
boomerang; P-T diagrams and melting paths; isotope decay)
Bring:
Calculator, Chart of the Nuclides, Periodic Table