Diffusion in the Earth Sciences: Theory and Applications (Short Course)

April 2nd to April 5th 2019

Lukas Baumgartner

Dr. Michael Jollands, UNIL

Dr. Elias Bloch, UNIL

Dr. Michael Jollands, UNIL

Dr. Elias Bloch, UNIL

Prof. Lukas Baumgartner, UNIL

Dre. Sylvie Demouchy, University of Montpellier, France

Prof. James Van Orman, Case Western University, USA

Understanding diffusive processes is important for researchers working in many branches of the earth and planetary sciences, yet few geological programs offers students a full course in diffusion kinetics. This short course will provide students with a comprehensive theoretical background of diffusion, followed by practical exercises in geological problems. The course will be given as a series of 1 hour lectures, followed by 1-2 hour practical exercises with content related to the previous lecture. The majority of the course will be taught by two post-doctoral researchers at Unil – M. Jollands and E. Bloch – along with Prof. L. Baumgartner, and two invited guest lectures: James Van Orman (Case Western University, USA), Sylvie Demouchy (University of Montpellier, France).

Full program:

Day 1 MORNING SESSION Lecture: M. Jollands Introduction to diffusion: Introduction to applications, Fick's laws and the error function Practical Exercise: Error function curves, sensitivity to various variables (diffusion coefficients, time, distance, units)

AFTERNOON SESSION Lecture: E. Bloch Arrhenius relationships, diffusion nomenclature, diffusion length scales Practical Exercise: Determining diffusion coefficients from Arrhenius relationships. Multiple elements, single mineral/multiple minerals, same element. Applicability to different geological processes. DAILY SUMMARY (30 minutes)

Day 2 MORNING SESSION Lecture: E. Bloch Some complexities of diffusion: diffusive anisotropy, multicomponent diffusion Relation to crystal structures, charge-balance. Practical Exercise: Understanding the difference between simple diffusion (as in day 1) and multicomponent diffusion in terms of length scales, profile shapes.

AFTERNOON SESSION Lecture: M. Jollands Experimental petrology – how we obtain diffusion data. Introduction to experimental and analytical techniques. Practical Exercise: Determine diffusion coefficients from experimental data. Then, determine Arrhenius relationships from diffusion coefficients at multiple temperatures. DAILY SUMMARY (30 minutes)

Day 3 MORNING SESSION Lecture: L. Baumgartner Diffusion in fluids/melts, treating diffusion in rocks (vs. single minerals ca day 1-2). Practical Exercise: Diffusion in melts.

AFTERNOON SESSION Lecture: M. Jollands, E. Bloch, L. Baumgartner 3 x applications of diffusion relating to geospeedometry, thermochronology, geochronology. Practical Exercise: Choice of 3 x practical exercises relating to the previous lecture, depending on students' interests. DAILY SUMMARY (30 minutes)

Day 4 MORNING SESSION Invited lecture: Sylvie Demouchy, University of Montpellier, France. Magma ascent rates from H diffusion in xenoliths/crysts. Practical Exercise associated to invited lecture (or alternative exercise prepared by course leaders)

AFTERNOON SESSION Invited lecture: James Van Orman, Case Western University, USA. Diffusion-controlled stable isotope fractionation. Practical Exercise associated to invited lecture (or alternative exercise prepared by course leaders) DAILY SUMMARY (30 minutes)

Lausanne

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