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GEOL 335 - Plate Tectonics

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Picture of the Sinai Peninsula taken from the Apollo 7 spacecraft

SYLLABUS for GEOLOGY 335: Plate Tectonics  

Instructor: Dr. Grant R. Woodwell Office: 440 Jepson Science Hall Phone: 654-1427
e-mail: gwoodwel or gwoodwel@umw.edu

Office hours: Mon. - Tues. - Wed. - Fri. : 11:00 - 12:00 a.m.
Other times available by appointment.

Class meeting times: Tuesdays and Thursdays from 9:30 - 10:45 a.m. in room 409 Jepson
Science Center.

Laboratories: Thursdays, 2:00 - 4:45 p.m. in room 409 or 407 Jepson Science Center.

Course Objectives : To this point you have been exposed to the theory of plate tectonics in a somewhat piecemeal fashion. Typically, students receive an overview of the theory in an introductory course, consequences of plate motions are discussed in the Evolution of the Earth class and some selected facets are explored in upper level courses, such as petrology or structural geology. This course provides a framework to explore the theory of plate tectonics exclusively and in some detail. We will begin by assessing the state of geological knowledge that is post-Catastrophism or Neptunism but pre-plate tectonics. Using a historical approach, we will then explore the key observations and experiments that led to the general acceptance of the theory by the early 1970's. Students will also have opportunities, through projects and presentations, to assess geologic and geophysical events that occur at selected plate boundaries. Related subjects include elements of seismology, geophysics, paleomagnetism, tectonics and petrology. An important component of the course is the laboratory experience. You will have the opportunity to perform many of the calculations that originally led to the general theory of plate tectonics and also discover how to make reconstructions of previous plate positions.

Prerequisite : Students must have completed GEOL 112: Evolution of the Earth or an equivalent second semester historical geology class at another institution.

Texts : Cox, A. and Hart, R.B. (1986), Plate Tectonics: How it Works. Blackwell Scientific Publications, Inc.
Kearey, P and Vine, F.J., (1996), Global Tectonics, 2nd Edition. Blackwell Science.
Additional reserve readings will be provided.

Exam Schedule : Two in-class examinations plus the final exam which is cumulative.
Final exam: Thursday, May 1st (8:30 - 11:00 a.m.)

Presentations : Oral communication skills are of vital importance for success in the professional workplace. In addition, the work that goes into preparing a presentation for a group helps to focus the learning process. For these reasons each student will be responsible for four separate presentations. Two of these talks will be associated with an on-going laboratory project that involves a study of earthquake behavior at selected subduction zones. Students will monitor specified active margin regions via the Internet and provide two separate reports to the class on their findings. The other two reports will be conducted during the lecture component of the course. The topics of these presentations will be related to specific geophysical and geological features of plate boundaries. Examples of appropriate topics include the petrology of mid-ocean ridge basalts, seismicity of subduction zones, gravity anomalies at ridges, and heat flow studies.

Course Grade : Final grade is determined by weighing the exams, presentations and labs as
follows:
Presentations 20 %
Laboratory 25 %
Exam I 15 %
Exam II 15 %
Final Exam 25 %

Honor Code : Material submitted for a grade, such as exams and laboratories, must be pledged. It is certainly permissible for students in the course to share ideas and problem solving strategies, but it is expected that the final work represent your own effort.

LECTURE TOPICS

1 Historical beginnings to the plate tectonic revolution. What was the state of geological
knowledge in the mid- to late- 1800's? How did this early understanding of the Earth
shape ideas that were to follow?

2 The beginnings of the Theory of Continental Drift. How Alfred Wegener launched radical new ideas regarding the mobility of continental masses.

3 The modern era of Plate Tectonics begins. Starting with oceanographic surveys of the
1950's, and the newly discovered geomagnetic time scale, seafloor spreading is proposed
and the process of subduction is observed.

4 Overview of the internal structure of the Earth with emphasis on the planet's seismic
velocity structure and composition of the crust and mantle.

5 Geological evidence for continental drift. Updating Wegener's observations regarding
paleoclimate data, reconstructing Pangea, and paleomagnetism.

6 Seafloor spreading: what geologic and geophysical events occur at divergent plate
boundaries? First student lecture presentations.

7 Transform plate boundaries. How do the geologic activities of these boundaries differ
from other boundary types?

8 Subduction zone settings. Discussion will focus on differences between types of
convergent boundaries (ocean - ocean, ocean - continent and continent - continent).

9 Plate tectonics and mountain building events. Comparison of several types of mountain
ranges such as the Andes, Appalachians and Himalayas. Second student lecture
presentations.

10 Continental rift zones. Starting point for the Wilson Cycle?

11 Mechanisms of plate tectonic movement. How do we evaluate the probable driving forces? What is the role of mantle convection in the process?

12 Review of significant orogenic events in both Precambrian and Phanerozoic time.

13 Association of economic ore deposits with plate tectonic events.

Laboratory Topics

1 Introduction to plate movements on a hypothetical flat-Earth.

2 Study of relative plate velocities and resolution of velocity vectors.
Introduction to semester-long subduction monitoring assignment.

3 Introduction to triple junctions and tests of triple junction stability or instability.
Student lab presentation 1 (Background information on assigned subduction zone)

4 Using spherical coordinates and stereographic projections to represent the Earth.

5 Converting between Cartesian and spherical coordinate systems. Using linear algebra
tools to solve stereonet problems.

6 Finding Euler Pole locations using transform fault trends and seismic slip vectors.

7 Plotting plate positions in local coordinates. Expressing the orientation of faults and slip
vectors numerically and on stereonets.

8 Reading seismographs and interpreting seismic travel-time curves.

9 Spring Break Week

10 Using seismic first motion studies to determine focal mechanism solutions.

11 Reconstructing former plate positions using finite rotations. Determining the timing of
Euler pole jumps.

12 Calculating a finite reconstruction pole and using global circuits to understand relative
plate motion.
Second lab student talks (Conclusions drawn from long-term subduction monitoring)

13 Using the geomagnetic time scale to date ocean seafloor.

14 Locating geographic coordinates from paleomagnetic data.