SO461 Syllabus--Fall 2004

SO461 Home Page  Lecture

Mon 8/23 Course introduction
  1. Rock cycle implies geologic recycling, just like plate tectonics.
  2. Uniformitarianism, the present is the key to the past.
  3. Catastrophism is not a black box, but the product of the laws of nature we see operating today.
  4. Geologic time: 1mm/yr = 1km/My


Wed 8/25 Geologic time and dating

Reading: usgs geotime



  1. Differentiate relative and absolute dating.
  2. Understand the law of superposition, and the principal of original horizontality.
  3. Describe the principles involved in radiometric dating, and list some of the isotope pairs used.
  4. Know the geologic time scale.


Mon 8/30 Earthquakes and velocity structure 

GT 8-19

  • Understand the classification of igneous rocks based on texture or cooling (intrusive/extrusive), and chemical composition (mafic, intermediate, felsic)
  • Differentiate the three different types of faults, and give representative plate settings where they occur.
  • Given the orientations of the two focal planes and the compressional and dilational axes, plot a focal mechanism diagram and determine the type of fault represented.
  • Define the following earthquake terms: focus, epicenter, magnitude, and the three main types of waves (P, S, and surface).
Fault gouge
Wed 9/1 Earthquakes II
  • Differentiate the Richter and Mercalli scales
  • Discuss the plate tectonic settings, and rocks involved, in plutons, stratovolcanoes, shield volcanoes, and MORB
Qtz, Granite, Basalt
Mon 9/6

Labor Day

Wed 9/8 Crust, Mantle, and core 

GT 19-30

  • Discuss how we can use earthquake arrival times to determine the layering in the crust.
  • Describe the layers of the ocean crust, and how they corresponds to ophiolites.
  • Discuss the gross composition and structure of the mantle and core.
  • Key terms: gabbro, peridotite, pillow basalts, and sheeted dikes
Mon 9/13 Sedimentary rocks: 

Ocean Basins (SO231 text), p.114-120

  • Discuss the classification of sedimentary rocks as clastic or chemical, and the divisions by size.
  • Discuss where silica oozes, carbonates, red clays, terrigenous sediments, and ice rafted sediments occur, and why they have this distribution.
  • Discuss what the vertical sequence of rock types can tell about the history of the location.
  • Discuss the importance of rads, diatoms, forams, and coccoliths in the ocean sediments.
Wed 9/15 DSDP exercise DSDP/ODP Project  
Mon 9/20 Deformation, isostasy, and heat flow

 GT 30-45

  • Differentiate brittle and ductile deformation, and the conditions leading to each.
  • Differentiate the Airy and Pratt models of isostasy, and what is required for isostasy to operate on the earth.
  • Discuss why the thickness of the lithosphere varies depending on how we measure it.
  • Discuss how heat flow varies on the earth.
  • Differentiate free air and bouguer gravity anomalies
Wed 9/22 Continental drift and magnetism


  • Understand  how we use Euler's theorem to model motion on the earth's surface.
  • Discuss the kinds of evidence for plate motions, especially paleoclimates.
  • Describe how paleomagnetic sampling can reveal a paleo-latitude but not a paleo-longitude, and why that sometimes causes scientists to use apparent polar wander (APW) paths.
Mon 9/27


Sea floor spreading 


  • Discuss why marine magnetic anomalies form, and how they provided the clinching evidence for plate tectonics.
  • Discuss the use of magnetic anomalies to date the seafloor, determine spreading rates, and infer the former locations of plate boundaries.
Wed 9/29 Exam 1  
Mon 10/4


Framework of plate tectonics 

GT 76-102

  • Discuss recent absolute measures of plate velocities (GPS and VLBI)
  • Discuss the importance of hot spots in providing an absolute reference frame
  • Differentiate total reconstruction poles, stage poles, and instantaneous poles of rotation
  • Understand why motions of multiple plates on a sphere require that some of the rotation poles must move.
Wed 10/6 Framework of plate tectonics 

GT 76-102

Mon 10/11

Classes (Columbus Day)

Sidescan sonar and subbottom profiler  
Wed 10/13 Ocean ridges 

GT 103-121

  •  Discuss the characteristics of ridges in terms of plate spreading rate.
Mon 10/18 Transform faults 

GT 122-137

  • Describe the bathymetric expression of transform faults and fracture zones.
  • Differentiate right-lateral and left-lateral strike-slip faults.
  • Describe how motion along a ridge-offsetting transform differs from a classical strike slip fault.
  • Discuss what happens at transpressional and transtensional bends on strike-slip faults.
  • Describe leaky transforms
Wed 10/20 Transform faults 

GT 122-137

Mon 10/25 Paper 2 due

Subduction zones 

GT 138-173

  • Discuss the classification of metamorphic rocks in terms of pressure and temperature, and the explanation for paired metamorphic belts in terms of plate tectonics.
  • Describe the features associated with the subduction zone boundary: forearc bulge, trench, subduction complex, volcanic arc, backarc basin/marginal sea, and backarc ridge
  • Discuss the distribution of earthquakes across a subduction zone, and why they include both normal and reverse mechansims.
  • Key terms: blueschist, turbidites
Wed 10/27 Mountain ranges

GT 174-208

  • Differentiate Andean and collisional mountain belts
  • Discuss the distribution of earthquakes in an orogenic belt and the Benioff zone
  • Discuss how indentation tectonics works in southern Asia
  • Discuss how suspect terranes form, and how they might relate to oceanic plateaus
Mon 11/1


Mountain ranges

GT 174-208

Wed 11/3


Mon 11/8 HOL, weigh mud samples

Geology Exercise

Meet at Hendrix to weigh your sediment samples.  
Wed 11/10 Geology Exercise    
Mon 11/15 Sediment size distributions  
Wed 11/17 Rifts and sedimentary basins 

GT 209-247

  • Describe the rifting process, both when an ocean basin forms and an aulocagen forms
  • Describe the Wilson cycle
  • Discuss the thermal impact of stretching the crust, and the thickness of sediment that can accumulate.
  • Discuss how detachment faults and accommodation zones work in crustal extension in three dimensions.
  • Key terms: backstripping, foreland basins, inversion tectonics
Mon 11/22 Mechanisms plate tectonics 

GT 248-268

  • Discuss the problems with the expanding earth hypothesis.
  • Discuss the use of corals to calculate the length of the year.
  • Discuss the phi scale, and how it complicates interpretation of graphs with sediment size as one axis.
  • Discuss how the pipette method derives sediment size distributions.
Wed 11/24 Mechanisms plate tectonics

 GT 248-268

  • Discuss the distribution of heat flow in the earth's crust.
  • Describe how mantle convection could work.
  • Discuss the forces acting on plates
  • Discuss the areal distribution of convection cells.
Mon 11/29 Implications of plate tectonics 

GT 269-295

  •  Discuss how Archaen and Proterozoic plate tectonics might resemble or be different from current processes.
  • Discuss how plate tectonics affects economic geology, especially with fossil fuels, and climate-controlled deposits like laterites, bauxite, and evaporites
  • Key terms: greenstone belts, granulite gneiss, source/ trap/seal.
Wed 12/1 Paleo-oceanography  and Paleoclimatology 
  • Discuss the use of isotopic studies (d13C or d18O) to infer past temperatures or mixing in the oceans
  • Discuss what happens to the Black Sea in a glaciation when global sea level drops
  • Describe how geologic evidence can suggest the direction of flow into or out of a stratified body of water like the Black Sea
  • Discuss why the behaviour of climate and ocean circulation on geologic time scales can be beneficial for current issues like global climate change
Mon 12/6 Course review
  • Discuss the role of geologists as historians of the earth, and why this has practical applications
  • Describe how catastrophes can be incorporated in a uniformitarian view of geologic history.
  • Appreciate the differences between the geology of the oceans and the continents. 
Wed 12/8

Friday Class Schedule



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