Professor: Kurt Hollocher
Phone: 388-6518
e-mail: hollochk@union.edu
Web site: http://www.union.edu/PUBLIC/GEODEPT/COURSES/geochemistry/
Text: Geochemistry, 2nd Edition, by Arthur Brownlow
| Dates | Read chapters* | Subjects (subject to change) |
| Week 1 | 1, 3 | Chemistry of the universe, stars, nucleosynthesis, origin of the solar system, meteorites. LAB 1: Oddo-Harkins rule: element and isotope abundances |
| Week 2 | 5 | Ionic crystals, coordination, solid solutions, phase rule, partition coefficients. |
| Week 3 | 8 | Origin of the igneous rocks: melting, crystallization, binary and ternary systems. LAB 2: Crystal/liquid element partitioning and magmatic modeling |
| Week 4 | 2, p. 51-85 | Radiometric ages, K-Ar, Rb-Sr, U-Th-Pb systems. |
| Week 5 | 3 | Writing and balancing reactions, congruent and incongruent reactions. LAB 3: U-Th-Pb radiometric dating |
| Week 6 | 7 | Sedimentary rocks, soil development, solubility. |
| Week 7 | 4 | Dissolution, aqueous reactions, redox. LAB 4: Mineral weathering rates and weathering reactions |
| Week 8 | 6 | Chemistry of river waters on basin-wide scales: element sources and solubility constraints. |
| Week 9 | - | The atmosphere and oceans: sources, sinks, and global-scale geochemical cycling. LAB 5: Chemistry of natural waters: speciation and water-rock interactions |
| Week 10 | 2, p. 85-122 | Stable isotopes and isotope fractionation of H, C, O, S. |
| * There are additional suggested readings here. | ||
No final exam. Your grade will be based on:
- Grades on homework.
- Demonstration of your ability to use various computer and analytical techniques.
- Demonstration of your in-class understanding of the subject material.
- Grades on lab reports.
Lab exercises
| Lab | Subject | Analyses performed | Computer Work |
| 1 | Oddo-Harkins rule | Scan a basalt with the ICP-MS for all lanthanide isotopes; scan synthetic solutions for isotopes of tin and europium. | Plot line graphs of abundance vs. mass, abundance vs. atomic number, use evidence to support or refute the Oddo-Harkins rule. Calculate routine analytical statistics. |
| 2 | Crystal/liquid partitioning of trace elements in magmas | Hand pick phenocryst phases and matrix from a basalt, dissolve and analyze matrix, phenocrysts, and dacite glass. | Calculate and plot partition coefficients, model dacite as derived from the basalt by the processes of fractional crystallization and equilibrium melting. Use statistical methods to identify the best model. |
| 3 | Lead isotopes and radiometric dating | Dissolve and analyze apatite and calcite from a pegmatite sample. | Determine common and radiogenic Pb isotopes, U, and Th in a sample. Calculate Pb-U, Pb-Th, Pb-Pb, and concordia ages and evaluate in terms of the best age of the sample. |
| 4 | Dissolution rates and weathering | Soak mineral separates in deionized water, analyze water at intervals for major elements and pH. | Plot data, model the hypothetical dissolution reaction based on analyses, and calculate a dissolution model curve by least squares approximation. |
| 5 | Chemistry of natural waters | Analyze major and trace elements in natural water; measure pH, O2, alkalinity, temperature in the field. | Calculate ion and neutral species and mineral saturation indexes in water using the U.S.G.S. PHREEQ modeling software. Model water-rock interactions at different CO2 activities. |
About this course
This course will involve both lecture material and practical lab and computer work in geochemical techniques, processes, and modeling. In these labs we will examine a variety of geochemical problems. Every two weeks there will be a lab project that will be more or less tied to the lecture material. The geochemical problem being investigated in lab will be discussed during sample preparation, sample analysis, graphing the data, interpreting the data, and writing and running computer models. Most models and other calculations you will do yourselves on a spreadsheet.
Each lab will have a report due. These reports will involve simple calculations, constructing computer models on a spreadsheet, and graphing data, in addition to a 2 to 4 page writeup (4 double spaced page maximum!). In the write ups, all tables and figures must be cited sequentially in the text. I will read, comment on, and grade the lab reports. Grading will be based on completeness, quality of writing, and quality of the tables and figures. The lab reports should be concise and accurate, and written as though they were being submitted to a journal as a research article. Care should be given to writing and to presentation of the data.
WARNING: the worst problem in scientific writing is not understanding what you are writing about! If you do not understand your topic, you will not be able to convince anyone else you understand it.
The lab writeup instructions are here. Tips for better writing can be found here.