HR: 0830h
AN: ED41C-1187    [PDF]
TI: A Web Resource for Lab Activities Using SEM, EDX and Light Microscopy
AU: * Argast, A
EM: Argast@ipfw.edu
AF: Geosciences Dept. Indiana-Purdue University Fort Wayne, 2101 E. Coliseum Blvd., Fort Wayne, IN 46805-1499 United States
AU: Tennis, C F
EM: Tennisc@ipfw.edu
AF: Geosciences Dept. Indiana-Purdue University Fort Wayne, 2101 E. Coliseum Blvd., Fort Wayne, IN 46805-1499 United States
AB: A resource that facilitates undergraduate activities centered on the development of perthitic textures is available at http://www.geosci.ipfw.edu/sem/semedx.html. The web site provides a coherent set of data and images from a perthite and an anorthoclase sample. Backscatter and secondary electron images, plane- and cross-polarized light images, energy dispersive X-ray (EDX) data from 13 points on the perthite and 31 points on the anorthoclase (including spectra and results files with data expressed as wt. and atomic percents) and X-ray diffraction (XRD) data are available. Care has been taken to match the areas examined by light and electron methods, allowing students to directly compare the data available from each technique. Brief descriptions of the various methods are provided. The available information can be the basis for many different exercises. Those without easy access to mircoprobes or EDX spectrometers will find the spectra useful for discussions of microchemical techniques. Different phases can be identified in the light and SEM images. The chemical results can be used to calculate formulas. (In addition to the feldspar, the anorthoclase phenocryst contains olivine, clinopyroxene, ulvospinel, apatite and glass.) Feldspar compositions can be plotted to illustrate compositional differences in perthite and anorthoclase. Glass compositions from the interior and margins of the anorthoclase phenocrysts can be compared. Numerous other possibilities, of varying levels of complexity, exist. The perthite (from Perth, Ontario) and the anorthoclase (from Mt. Erebus, Antarctica) were purchased from Wards Natural Science. There are many students with little or no access to data derived from EDX, SEM, XRD and similar techniques. It is our responsibility to find ways to make this information more universally available to all students.
DE: 3600 MINERALOGY AND PETROLOGY (replaces
DE: 6605 Education
SC: Education and Human Resources [ED]
MN: 2003 Fall Meeting