Geol-7081: Stable isotope
Geochemistry: Principle and application (Fall 2009)
(TTh 9:30 to 11:00
am at Howe-Russell E202)
Instructor: Dr. Huiming Bao (Phone: 8-3419)
Office: E338 Howe-Russell,
LSU
E-mail: bao@lsu.edu; Website: http://geol.lsu.edu/hbao/
Pre-requirements: General
chemistry or basic physical chemistry, and Earth system history
Statement of Purpose
The
application of stable isotope ratios to physical, chemical, and biological
problems has been enjoying a great expansion for over half a century. Stable
isotope ratios are one of the most useful detective tools for understanding
processes in nature, especially for events that occurred in the distant past.
The goal of this course is to introduce concepts, principles, methodologies,
and cases of applications on the distributions of stable isotopes (e.g., C, O,
S, N, and H) in nature with applications on geological, environmental, and biological
problems. I will focus on universal principles that are applicable to isotopes
of different elements, and on quantitative understanding and handling of
fractionation processes.
Structure
Geol 7081 in fall 2009 will
not have a designated textbook. We will have several reference books (listed
below). Key reference papers will be distributed in class. There will be
reading assignments, problem sets, and discussion sessions. Each one of you
will play a leading role in discussing one particular topic of my random choice
at least ONCE in the semester (mostly in the second half of the semester). We
will have two session exams and a final term paper. Note that your problem sets
will be graded but the grades do not count towards your final grade.
We will have two classes per
week, among which > 6 hrs is on laboratory demonstration and training.
Reference books
1. Robert E. Criss: Principles of Stable Isotope Distribution, 1999
2. Zachary Sharp: Principle
of stable isotope geochemistry, Prentice Hall 2006.
3. Jochen
Hoefs,
4. Environmental Isotopes in
the Hydrological Cycle: Principles and Applications
VOLUME I: INTRODUCTION - THEORY, METHODS, REVIEW
by Willem G Mook,
5. Brian Fry: Stable Isotope
Ecology, Springer (December 21, 2007)
6. Isotopes : Principles and
Applications, Gunter Faure and Teresa Mensing, Third
Edition, 2004
7. Pier de Groot, Handbook of Stable Isotope Analytical Techniques.
See website
http://users.pandora.be/handbook/index.html
Grading
Problem
sets: 0% (total 7-8 sets)
Session exam I: 30% (Two parts: one close-notes and one open; Questions are
similar to those in problem sets)
Session exam II: 30% (Most questions are similar to those in problem sets)
Class
preparation, attendance, and performance: 15%;
Final
term paper: 25% (~10 pages -- size 11, Times New Roman, and
double-spaced)
I expect everyone read the weekly reading assignment and prepare to discuss the
subject in depth. Informal class discussion is a major component of the course.
Your grade will be judged by your performance in class discussion (10%) and the
session you chair (5%).
The topic of your final term
paper will be lotteried from a set of agreed topics
(see samples below). The term paper will be evaluated from the clarity of the
problem statement, the layout of the history of the problem, hypothesis, major
progresses, current debates, gaps of knowledge, and frontiers for further
study. The topic cannot be the same one that you have chaired in your
Discussion sessions.
Sample topics for your term
paper (you can have a much more focused topic than what are listed):
Isotopic evidence for
early life
Processes that could
result in extremely negative δ13C in carbonates
Processes that could
result in large positive δ13C shift in short geological interval
Processes that could result in large negative δ13C shift in
short geological interval
Isotopic evidence for the rising of molecular oxygen in the atmosphere
Kinetic isotopic fractionation during calcite precipitation
Oxygen isotope geothermometer
Carbon isotope fractionation during photosynthesis
Kinetic isotopic effect
during bacterial sulfide oxidation and sulfate reduction
Mass-independent isotope
fractionation
Extraterrestrial oxygen
isotope compositions
Nitrogen isotope variation
and its application in ecosystem
What controls the sulfur
and oxygen isotopic compositions of seawater sulfate?
Exchange or no exchange
(kinetics of isotopic equilibrium)
(more to add ......)
Syllabus (will be updated):
Week 1
Introduction: Basic concepts and history: isotopes, abundances, a, R, s,
absolute ratio, standard, and isotope-ratio mass spectrometers (lab tour).
Problem set I out
Week 2
Cases showing the wide
spectrum of applications, key literature and journals, major players in the
past and present: older generation, current generation
Problem
set I due and Problem set II out
Week 3
Mechanisms of isotopic
fractionation: Unified separation theory
Molecular models
Problem set II due and
Problem set III out
Week 4
Equilibrium and kinetic
isotopic fractionation
Equilibrium:
Geothermometer.
Problem set III due
Week 5
Kinetic:
Rayleigh Distillation model, open- vs. close-system fractionation
Case study: hydrological system, biological sulfur oxidation and sulfate reduction
Problem set IV out
Exam I
Week 6
Kinetic: carbon isotope fractionation during photosynthesis
Labile and non-labile ions in solution and isotope exchange kinetics
Problem set VI due
Week
7:
Relations between δ17O and δ18O,
or δ33S and δ34S;
Changing isotope ratios of O and H in water, S and O in sulfate, N and O in
nitrate, and C and O in carbonate.
Problem set V out
Week
8:
Mass-dependent vs. mass-independent isotope fractionation
O and S Photochemistry
Week
9:
1. Student-chaired Discussion session I--- Problem set V due
Week
10
Application of oxygen and
sulfur isotope ratios in atmospheric chemistry
Week 11:
Fall Break
Week 12
1.
Origin of soil carbonate nodules, calcrete, and lake carbonates
2. Student-chaired Discussion session II
Exam
II (sometimes early November)
Week
13
Week 14:
Week 15:
Week 16:
New analytical techniques,
plus Discussion session VI
Week
17: Perspectives and emerging fields in stable isotope geochemistry
Final
term paper due at 5:00 pm Dec. 10, 2009.