GEOLOGY
489 (Geotectonics) Ñ Spring, 2004
University
of Illinois at Urbana-Champaign
Instructors
Steve Marshak NHB 302/253A 333-7705 smarshak@uiuc.edu
Michael Stewart NHB 250 244-5025 stewart1@uiuc.edu
Text (optional)
Moores, E.M., and Twiss, R.J., 1995, Tectonics, W. H. Freeman and Co., New York.
Books on Reserve (in the Geology Library)
¥ Brown, G.C. et al., eds., 1992, Understanding the Earth: A New
Synthesis:
Cambridge.
¥ Brown, G.C., and Mussett, A.E., 1993, The Inaccessible Earth, 2nd: Chapman and Hall.
¥ Condie, K.C., 1989, Plate Tectonics & Crustal Evolution (3rd
ed.): Pergamon
Press.
¥ Cox, A., and Hart, R.B., 1986, Plate Tectonics: How it works: Blackwell Scientific.
¥ Kearey, P., and Vine, F.J., 1996, Global Tectonics (2nd ed.): Blackwell Scientific Publ.
¥ Lillie, R.J., 1999, Whole Earth Geophysics: Prentice-Hall.
¥ Marshak, S., 2001, Earth: Portrait of a Planet: W.W. Norton & Co.
¥ Mussett, A.E., and Khan, M.A., 2000, Looking into the Earth: An
Introduction to Geologic Geophysics: Cambridge Univ. Press.
¥ Piper, J.D.A., 1987, Palaeomagnetism and the Continental Crust: Open Univ. Press.
¥ StŸwe, K., 2002, Introduction to the Geodynamics of the
Lithosphere: Quantitative Description of Geological Problems: Springer-Verlag
¥ van der Pluijm, B., and Marshak, S., 2004, Earth Structure:
Introduction to Structural Geology and Tectonics (2nd ed.): W.W. Norton & Co.
¥ Windley, B.F., 1995, The Evolving Continents (3rd ed.): John Wiley & Sons.
Class Format
The class will be a mix of traditional lecture (with one of
the instructors lecturing on a given topic), student presentations, and class
discussion. The instructors will provide you with background information and
attempt to bring everyone to the same level of understanding from which we can
launch into the remainder of the class.
Student Presentations
Each student must choose at least three topics form the list
below and prepare a presentation for the class. To the extent possible, base your presentation on recent scientific literature, focusing on
advances in or challenges to accepted/favored hypotheses. See one of the
instructors ahead of time with a list of references so we can insure you are
following a fruitful path. One week prior to your scheduled presentation, you
should provide the class with a reference to one journal article that will
serve as the basis of discussion during/after your presentation. You should
either put a Xerox of the article on reserve in the Geology Library, or put a
PDF of the article on the Library's web page. On the day of your presentation,
provide the class with an outline, figures from your presentation, and a list
of references (in JGR format) from your research into the topic.
Participation
This class will only succeed if you participate by reading
the papers provided and being prepared to discuss the topics during class.
Thus, please plan to prepare for classes in advance, and come to class armed
with questions.
Final Exam
The final exam will be written and will be comprehensive.
Both faculty and student presentations will be fair game. The format of the
exam will be clarified toward the end of the semester.
Course Grade
Your grade will be based on: Participation (30%); Oral
presentations (35%); Final Exam (35%).
GEOLOGY 489 (Geotectonics) Ñ List of Topics
Topic A:
History of geotectonic concepts
á
Early concepts of
geotectonics.
á
Contraction theory.
á
Geosyncline theory.
á
Expanding Earth idea.
Topic B:
Birth of plate tectonics theory
á
Wegener and continental
drift.
á
Hess/Dietz and seafloor
spreading.
á
The proof of seafloor
spreading.
á
A scientific
"revolution"
Topic C:
Paleomagnetism
á
Magnetic fields,
susceptibility; rock magnetism
á
Polar-wander paths
á
Seafloor magnetic
anomalies.
á
Magnetostratigraphy.
á
Topic
for Student Presentation:
o
Recent
model of the geodynamo, and the cause of magnetic reversals.
Topic D:
EarthÕs internal structure and composition
á
Seismically defined
whole-Earth layers.
á
EarthÕs composition.
á
Nature of lithosphere,
asthenosphere, and "tectosphere".
á
Mantle convection.
á
Mantle plumes.
á
Topic
for Student Presentation:
o
Mantle
convection models.
o
Geophysical
evidence for mantle plumes.
o
Origin
of the Columbia River basalts.
o
Evolution
of the Yellowstone "hot spot."
Topic E:
Plate kinematics
á
Relative plate velocity
á
Absolute plate velocity
á
Triple Junctions
á
Topic
for Student Presentation
o
Variation
in spreading velocity on the Mid-Atlantic Ridge.
o
Eurasian-North
American plate boundary north of Iceland.
o
Change
in Pacific plate motion: evidence from Hawaiian-Emperor and Louisville Seamount
chains, arguments against change(?).
o
Triple
junction configuration at the Galapagos, Easter, or Juan Fernandez Microplate.
o
Subduction
of spreading centers and the evolution of the triple junctions. (choose a
specific example to work with).
Topic F:
Plate Driving Mechanisms
á
Mantle convection
(basal drag?)
á
Ridge-push force.
á
Slab-pull force.
á
Trench suction.
á
Supercontinent cycle.
á
Topics
For Student Presentations
o
Rollback
of Scotia Arc subduction zone
o
Mantle
"return flow" at convergent boundaries.
o
Evaluation
of evidence for and against one of the mechanisms.
o
Balance
of forces models.
o
Latest
ideas concerning the validity of the supercontinent cycle.
Topic G:
Oceanic Lithosphere & Mid-Ocean Ridge Processes
á
Adiabatic Decompressive
Melting.
á
Morphology of a MOR:
fast- vs. slow-spreading.
á
Structure and
composition of normal oceanic lithosphere: ophiolites, seismic data.
á
Tectonic windows into
slow-, intermediate- and fast-spread oceanic crust.
á
Crustal construction at
fast-, intermediate- and slow-spreading ridges.
á
Evaluation MOR magmatic
models .
á
Topics
For Student Presentations
o
Magmatism
and spreading on ultra-slow spreading ridges.
o
Results
of the MELTs experiment.
o
Hydrothermal
vents, vent communities on MORs.
o
Melt
migration through the oceanic lithosphere, construction of the lower crust,
upper mantle and nature of the Moho.
o
Mantle
flow beneath the oceanic lithosphere
o
Evidence
for or against melt lenses beneath slow spreading ridges.
o
Geology
of the Oman Ophiolite.
o
Steady-state
magma chambers beneath MOR.
Topic H:
Convergent-margin tectonics
á
The subduction system:
trench, accretionary prism, volcanic arc.
á
Styles of back-arc
tectonics.
á
Seismicity at
convergent margins.
á
Flux melting.
á
Curvature of subduction
zones.
á
Topics
For Student Presentations
o
Arguments
for and against slab melting.
o
Along-
and across-arc variations in magma composition.
o
Initiation
of subduction.
o
Tomographic
evidence for and against ÔdeepÕ subduction below 600 km discontinuity.
o
Application
of critical-taper theory to accretionary prisms.
o
The
tectonic evolution of the Japan Sea.
o
The
origin of ultra high-pressure metamorphism in Subduction Zones.
o
Explanations
for the Laramide orogeny (USA), and the Pampean Ranges (Argentina).
Topic I:
Continental crust and continental-interior tectonics
á
Character and divisions
of the continental crust.
á
Origin of cratons.
á
Intracratonic basins
and structures.
á
Continental interior
fault-and-fold zones.
á
Topics
For Student Presentations
o
The
lower crust: nature and composition.
o
Nature
of the Moho beneath continental crust.
o
New
Madrid seismic zone.
o
Erosion
rates in continental interiors (past and present).
o
What
causes "cratonization" in continents?
Topic J:
Strike-slip fault systems
á
Tectonic setting of
strike-slip systems.
á
Transform vs.
transcurrent faults.
á
Transpression and
transtension.
á
Topics
For Student Presentations
o
Lateral
escape of Turkey: North & East Anatolian fault systems.
o
Predicting
earthquakes on the San Andreas fault system.
o
The
Alpine fault, New Zealand
o
Tectonic
evolution of the Los Angeles basin, California.
o
Tectonic
evolution of the Dead Sea.
Topic K:
Crustal Rifting
á
Stages and geometries
of rifting
á
Causes and evidence of
Rifting
á
Rock assemblages in
rifts
á
Topics
For Student Presentations
o
Metamorphic
core complexes in Basin and Range.
o
Evolution
of the East African rift.
o
Precambrian
rifting in North America.
o
The
GLIMPSE seismic-reflection lines of the Mid-Continent rift.
o
Tectonic
history of the Basin and Range Province.
o
Structural
architecture of the Basin and Range province.
o
Mesozoic
rifts of eastern United States.
Topic L:
Continental Collision
á
Basic stages during
collisions.
á
Fold-thrust belts
á
Other consequences of
collision (plateaus; slip lines; collapse)
á
Topics
For Student Presentations
o
Obduction
of ophiolites.
o
Orogenic
(extensional) collapse in Tibet.
o
Lithospheric
delamination.
o
Accretion
of exotic terranes.
o
Tectonic
context of the south Tibetan detachment, and its relation to the Main Central
Thrust in the Himalayas.
o
Mantled
gneiss domes in collisional orogens.
o
Ultra
high-pressure phases in collisional orogens.
Topic M:
Precambrian Tectonics
á
Archean high-grade
gneiss belts (origin of the TTG assemblage).
á
Archean
granite-greenstone belts.
á
Proterozoic orogenies.
á
Assembly of Gondwana.
á
Topics
For Student Presentations
o
Evolution
of Rodinia and Panotia (Neoproterozoic supercontinents and SWEAT)
o
Polar-wander
paths for Precambrian continents.
o
The
Dharmara orogen (ensialic orogens).
o
Stromatolite
evolution.
o
The
nature of Pan African orogenies, in Africa.
o
Architecture
of the Superior Province.
o
The
Penokean orogeny.
Topic N:
A Brief Synopsis of Phanerozoic tectonics in the conterminous USA
á
Tectonics of the
Appalachian orogen.
á
Tectonics of the
western Cordillera.
á
Topics for Student
Presentations
o
Tectonic evolution of
the Colorado Plateau
o
The Antler orogeny.
o
Tectonic evolution of
the Ouachitas.
Topic O:
Examples of Orogens Elsewhere in the World
á
Topics
for Student Presentations
o
Brief
tectonic evolution of the Alps (Switzerland and Italy).
o
The
tectonic evolution of the Altaids (central Asia) and the "Turkic"
style of deformation.
o
Brief
tectonic evolution of a portion of the Andes.