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Geodynamics-based Core Curriculum @ the University of Minnesota (UMN) - Twin Cities Martin O. Saar [email protected] Donna L. Whitney [email protected] 2) Overview Geodynamics I and II are required courses for geology, geophysics, and geological engineering majors. These courses introduce quantitative aspects of the geosciences - both solid (Geodynamics I) and fluid (Geodynamics II) Earth dynamics. These courses have chemistry, math, and physics prerequisites, but Geodynamics I does not have a geology prerequisite. The courses are team-taught, typically by a geologist and a geophysicist. 4) Geodynamics-II course content Fluids and fluid motion play major roles in numerous geologic processes on Earth's surface and interior. This course provides a quantitative introduction to the geologic fluids that shape our dynamic planet. Emphasis will be placed on mastering basic concepts in fluid mechanics and applying these concepts to a wide range of geologic problems. Goals include: (i) exploring important fluid systems of the Earth, such as atmosphere, rivers, groundwater, glaciers and magmas; (ii) providing an introduction to basic concepts in fluid mechanics, such as laminar versus turbulent flow, viscosity and convection; (iii) illustrating application of basic ideas, such as derivatives and integrals in mathematics to earth science problems; and (iv) developing the habit of thinking analytically and quantitatively. Students will be tested on both key vocabulary and applications of the material covered in lecture to geologic problems. The latter will involve both clear, qualitative explanations of the mechanics involved as well as mathematical, quantitative analyses and calculations. 1) Why have a geodynamics-based core curriculum? The courses teach quantitative skills and emphasize a wide range of processes at different spatial and temporal scales. This gives students a solid basis for seeing the links links between various Earth processes and materials - from the surface to the core, from water to melt. 3) Required geology courses - Geology B.S. Sophomore Year Geo 2201: Geodynamics-I Geo 2301: Mineralogy Geo 2303: Geochemical principles (writing intensive) Geo 2302: Petrology summer: introductory field camp (3 weeks) Junior Year Geo 3202: Geodynamics-II Geo 4501: Structural Geology Geo 3401: Geochronology & Earth History Geo 4602: Sedimentology & Stratigraphy summer: either advanced field camp or writing-intensive hydrogeology field camp (3 weeks each) Senior Year Geo 4631: Earth Systems: Geosphere/Biosphere Interactions Geo 3401: 2 workshop courses (chosen from selection) Numerical simulation of the relative speed of fluid flow around a sphere (introduced during lecture). In the lab exercise, students drop steel spheres in glycerin and measure the settling velocity to determine the glycerin’s viscosity using Stoke’s law. 5) Geodynamics-II laboratory exercises An integral part of the geodynamics courses are applications of math, physics, and chemistry to geoscience problems and hands-on learning experiences in form of weekly laboratory sessions where students conduct experiments such as: Darcy tube experiment (a: schematic and b: laboratory setup) to determine a granular material’s permeability or hydraulic conductivity. a b • Applications of calculus to problems involving fluids • Calculations of shear stress and pressure • Problems related to mass balance • Debris flow experiment • Fluid pressure and rock fracture lab • Glacial flow experiment • Darcy tube experiment • Stoke’s law experiment and Reynolds number • Postglacial mantle rebound experiment A high-viscosity silicon gel is indented with a weight prior to the lab. During the lab, the weight (“glacier”) is removed and the rebound of the gel is measured using a direct current displacement transducer (DCDT). Students then plot displacement as a function of time and use equations learned in class to determine the gel’s (“mantle’s”) viscosity. In this lab, students use a flume at UMN’s National Center for Earth Surface Dynamics to study water and sediment motion. Students vary the slope of the stream bed as well as the outlet flow and measure the stream surface velocity. Students also observe variations in sediment motion. • Flume experiment • Mantle convection experiment Glycerin and a few drops of dye are heated from below in a Petri dish while temperature is measured at the bottom and the top of the fluid column. Students then use their measurements to determine the Rayleigh number for different intensities of convection as indicated by different convection patterns. April 25-27, 2007 6) Concluding remarks Undergraduate students in the Geology and Geophysics Department at UMN take geodynamics-I as soon as they enter the geoscience curriculum. This course prepares them early on to think in quantitative ways about the Earth Sciences and it prepares them for the more quantitative geodynamics II course a year later. The goal of geodynamics I and II is to integrate the fundamental sciences with the geosciences so that students can learn how the other sciences can be applied to studies of the Earth and to
