GEOL 8750 : SILICATE GLASSES, LIQUIDS AND MAGMAS Dr. Alan Whittington Room 312, Geological Sciences [email protected] Phone: 884-7625 Meetings: MWF 12:00 - 1:15 Room 207, Geological Sciences Prerequisites: GEOL 3900 and GEOL 4700, or GEOL 8160, or instructor’s consent Required text: Silicate Glasses and Melts: Properties and Structure by B.O. Mysen and P. Richet, published by Elsevier, Developments in Geochemistry 10, 2005. ISBN 0-444-52011-2. Other Texts: *Structure, Dynamics and Properties of Silicate Melts by J.F. Stebbins, P.F. McMillan, and D.B. Dingwell (eds), Mineralogical Society of America, Reviews in Mineralogy vol. 32, 1995. ISBN 0 939950 39 1 *Volatiles in Magmas by M.R. Carroll and J.R. Holloway (eds), Mineralogical Society of America, Reviews in Mineralogy vol. 30, 1994. ISBN 0 939950 36 7 * both available in paperback for $24 each with MSA membership Encyclopedia of Volcanoes, by H. Sigurdsson, (ed) Academic Press, New York, 2000. ISBN 0-12-643140-X Course Description: This course is primarily designed to serve as an introduction to the physical properties of silicate liquids, glasses and magmas for graduate students who will be doing volcanological research in the experimental petrology laboratory. It is open to all qualified students however, and would be a useful course for students doing research in any branch of igneous petrology, or certain fields within materials science / engineering. It can be split into two main components: Part 1: Introduction to rheology and thermodynamics of glasses, liquids and magmas (~7 weeks). This will introduce the glass transition, and geologically important physical properties (density, viscosity, heat capacity, etc). We will explore techniques for their measurement, the effects of pressure, temperature and composition on these properties (especially volatile content), and the theoretical (thermodynamic) basis for current models of physical properties. Part 2: Application to physical volcanology (~7 weeks). Putting the theoretical and practical components into a volcanological context, using arc volcanoes (e.g. Santiaguito and Mt. St. Helens dacite domes) as case studies. We will investigate changes in the physical properties of magma due to changing bulk composition, crystallinity, temperature, volatile content and strain rate accompanying magma ascent, crystallization and eruption. Grading: A/F or S/U (standard grading), 3 credit hours Homework writing assignments 45% Discussion / participation 15% Term paper (research proposal) 30% Research presentation 10%Weekly readings will include one or two chapters from Mysen and Richet, and occasionally the Reviews in Mineralogy books, and between one and three literature papers. Typically there is a homework attached (summarizing a paper, for example) and I will assign different papers to each student. Clearly written summaries (to be provided to other students) and a willingness to lead a discussion are important for this course to work, hence 75% of the grade is on written work and 25% on discussion participation and presentation. The other major course aim is to develop a research proposal; this should NOT be your dissertation topic but can be related – check with Alan first. A pre-proposal (to check that the idea is feasible) and first draft (to help with organization, not to correct typographical errors) will be submitted prior to the final submission deadline, and returned promptly with suggestions. The proposal should follow standard NSF layout and guidelines, but can be shorter (minimum 7 pages or 2000 words). A 15-minute presentation is also required; this will be worth 10% of the final grade (with 30% coming from an assessment of the written proposal). Provisional course outline: Part 1 – introduction to rheology and thermodynamics of glasses, liquids and magmas 1. Introduction: Silicate Glasses, Melts and Magmas (M&R chap 2) 2. Structural relaxation and the glass transition (M&R chap 3; RM32 chaps 1 and 2) 3. Empirical models for silicate liquid viscosity (assigned readings from the literature) 4. Rheology and configurational entropy (M&R chap 4; RM32 chap 3) 5. Mixing properties and structure of silicate melts (RM32 chap 6) 6. Effect of volatiles on the physical properties of silicate melts (M&R chaps RM30 chap 9) Part 2 – application to physical volcanology 7. Introduction to Dacite Domes and other Volcanoes (assigned readings from the literature) 8. Volatile solubility in magmas (RM30 chaps 4 and 5) 9. Pre-eruptive volatile contents of magmas (RM30 chap 8) 10. Magmatic degassing and fragmentation (RM30 chaps 10 and 11) 11. Crystals and magma rheology (assigned readings from the literature) Assignments: (in addition to weekly readings). Weeks are when the assignment is due: Week 2: 1 page chapter summary (3%) Week 3: Summarize chapter using 1 sentence per paragraph (3%) Week 4: Literature search, using GeoREF / GeoBASE (3%) Week 5: Abstract of assigned literature paper (3%) Week 6: 1 page summary of literature paper of choice (5%) Week 7: 10-minute informal presentation on a physical property other than viscosity (10%) Week 8: Literature search, Santiaguito / Fuego / other, using GeoREF / GeoBASE (3%) Week 9: 4-page introduction to Santiaguito / Fuego / other volcano (15%) Week 10: One-page summary of research proposal due (pre-proposal) Week 11: SPRING BREAK Week 12: Work on research proposal Week 13: First draft of research proposal due (to be returned to you within 1 week) Week 14: Work on research proposal Week 15: Work on research proposal Week 16: Last week: 15 minute presentation of research proposal, and submit proposal.Policy on attendance: Attendance at every scheduled class is mandatory unless excused in advance. Each unexcused absence is -1% from the 15% allotted to discussion / participation. Policy on late submission of homework or term paper: Deadlines for submission of homeworks or the term paper will be clearly stated when each piece of work is assigned. No submission deadline will be less than seven days from the date at which the work was assigned. Every half-day increment past the deadline will incur a penalty of 10% of the available score for that piece of work (i.e. between 1