Course Logistics

Our understanding of plate tectonics and orogenic processes relies on detailed knowledge of the timing and rates of crystallization, metamorphism, deformation, and exhumation of rocks in the crust. Radioisotopic and cosmogenic dating provide the geochronologic, thermochronologic, and exposure age constraints necessary for understanding the dynamics of tectonic systems. The course will introduce fundamental processes behind the use and interpretation of geo- and thermochronologic data, including radioactive decay and growth, diffusion in minerals, and conduction and advection of heat in the crust. This will be followed by examples of how these techniques are used to study tectonic and geomorphic processes. Readings from chapters, papers, and other sources will serve as starting points for lectures and discussions. To reinforce your understanding and quantitative grasp of the concepts, there will be several complementary components to the class meetings:

1) Six problem sets, dealing with analytical solutions of diffusion of heat and chemical species and data reduction/interpretation for several different radioisotopic systems.

2) Students will lead 2-3 class discussions of a current issues/papers.

3) Students will write a short final paper and make an oral presentation to the class on an investigation, model, proposal, or other type of project of his or her choice.

Tentative Schedule

Day	General topic/PI	Specific topic	Reading
9/5	Introduction	Examples to motivate the issues, illustrations of current problems,
9/10	PR: Radioisotopic decay and growth	Decay, equations, examples, isochrons	Text chapters TBA
9/12	MB: Diffusion	Constant T	McDougall & Harrison
9/17	MB: Diffusion	Changing T, isotopic closure	McDougall & Harrison
9/19	MB: Thermal modeling	t-T histories of rocks	McDougall & Harrison
9/24	PR: ⁴⁰Ar/³⁹Ar dating	Micas, hornblendes	McDougall & Harrison
9/26	PR: MDD and K-spar Ar dating	Multi-domain diffusion models, modeling t-T paths	McDougall & Harrison
10/1	PR: Fission-track	Methods/application examples	Gallagher AREPS
10/3	PR: (U-Th)/He	Methods/application examples	Reiners Eos
10/8	MB: Cosmogenic dating	Methods/application examples	Bierman
10/10	PR: Plutons	Thermal histories of plutons	Harrison? TBA
10/15	MB: Metamorphic rx	Thermal histories of metamorphic rx	TBA
10/17	MB: Core complexes	General overview	Wernicke; Baldwin
10/22	MB: Normal faults	Slip rates, footwall thermal histories	Foster & John
10/24	PR: UHP rocks	UHP exhumation	Hacker
10/29	MB: Subduction wedges	Thermal histories of rocks in wedges	Batt
10/31	GSA meeting
11/5	GSA meeting
11/7	RETREAT meeting
11/12	RETREAT meeting
11/14	PR: Basin analysis	Thermal histories/structures of basins	Mahon Ar/Ar
11/19	MB: Regional study		TBA
11/21	PR: Analytical techniques	Mass-spectrometry, ICP-MS	TBA
11/26	PR: Detrital thermochron		Bernet, Garver
11/29	Thanksgiving
12/3	Thanksgiving
12/5	MB: Geomorphology	Dating topography	House, Braun
12/10	MB: Geomorphology	Drainage basin scale erosion	vonBlankenbur; Grainger
12/12	Final project presentations

Problem Sets:

Thermal modeling of pluton emplacement, uplift
Diffusion of He
Data interpretation: Ar and He chronometric data; error propagation
Steady-state solution for isotherms in a wedge; geothermal gradients
Data interpretation: cosmogenic dating and erosion rates
Age-elevation relationships in low-T thermochronometry; effects of topography and relief change

Supplementary material for this course:

We recommend that you buy either one of these books as a reference for use in, and use long after, this class:

· Radiogenic Isotope Geology, by Alan P. Dickin, 1995, Cambridge University Press, 490 pp, ISBN 0-521-43151-4.

· Principles of Isotope Geology, 2^nd Ed., by Gunter Faure, 1986, John Wiley & Sons, 589 pp, ISBN 0-471-86412-9.

Another useful reference:

· Geochronology and Thermochronology by the ⁴⁰Ar/³⁹Ar Method, 2^nd Ed., by McDougall, I., and Harrison, T.M., 1999, Oxford University Press, 269 pp.