SO461 Syllabus--Spring 2002



  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


  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 uses.
  4. Know the geologic time scale.


  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).


   Earthquakes II
  • Differentiate the Richter and Mercalli scales
  • Discuss the plate tectonic settings, and rocks involved, in plutons, stratovolcanoes, shield volcanoes, and MORB




  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


  Out of class exercise Obtain simplified core records for the 10 DSDP/ODP holes nearest your paper area, using either the library or leg  reports:


  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.


  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 crust and plates varies depending on how we measure it.
  • Discuss how heat flow varies on the earth.


  Continental drift and magnetism GT46-61
  • 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.


x-week Sea floor spreading GT62-75
  • 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.


x-week  exam comp time  


x-week  exam in x-period, Michelson 103  




  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.


  Ocean ridges GT 103-121
  •  Discuss the characteristics of ridges in terms of plate spreading rate.


  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



  Subduction zones GT 138-173
  •  Discuss the classification of metamorphic rocks in terms of pressure and temperture, 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 mechanisms.
  • Key terms: blueschist, turbidites


Spring Break    


Spring Break    


  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


  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


  Regional tectonics exercise  


  Rifts and sedimentary basins GT 209-247  




x-week  exam comp time  


x-week  exam in x period  


  Exam review  


  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.


  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.


  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.


  Paleo-oceanography  and Paleoclimatology (GSA Today)
  • Discuss the use of isotopic studies (d13C or d18O) to infer past temperataures 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


  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. 




1/8/2002 Stereonet


  1. Understand the concepts for dip and strike
  2. Plot a plane on a stereo net
  3. Determine the dip and strike of a plane from its projection.
  4. Plot a line on a stereo net.
  5. Determine the orientation of a line from its projection.
  6. Understand how we can plot a plane as a point on the projection (the pole).
1/15/2002 Quiz and Stereonet 2


  1. Interpret earthquake focal mechanisms
1/22/2002 Earthquakes and Volcanoes  D10
  1. Understand where shield volcanoes and stratovolcanoes occur.
  2. Describe why earthquake databases have few records of very large or very small quakes.
  3. Discuss why both Ms and Mb scales exist for earthquakes.
1/29/2002 Stratigraphic correlations 1.  Differentiate lithostratigraphy and chronostratigraphy
2/5/2002 Sea floor features
  1.  Interpret bathymetric patterns at seismic and aseismic ridges.
  2. Use the pattern of sea floor crustal ages to infer the plate tectonic history of a region.
2/12/2002 Plate rotations and magnetic anomalies  
2/19/2002 Plate motions and triple junction stability (read GT 95-102 before lab)  
2/26/2002 Sediment size distributions
  1. Discuss the use of the Shepard ternary diagram for sediment size classification.
3/5/2002 YP Lab Sediment sampling
3/19/2002 YP Lab Sediment sampling
4/2/2002 YP Lab Sediment sampling
4/9/2002 Rickover Sediment analysis and distribution study
4/16/2002 Rickover Sediment analysis and distribution study
4/23/2002 D10 Seismic reflection profiling