16 Undergraduate Research (Posters)
Thursday, 20 March 2008
8:00 AM - 12:00 PM
PETROLOGY AND GEOCHEMSTRY OF PILLOW BASALTS IN THE EASTERN ELK OUTLIER OF SOUTHWESTERN OREGON
Paper number: 16-14
Program: THEME SESSIONS
Time: 8:00 AM – 12:00 PM
Authors
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Mario J. GiaramitaCalifornia State University Stanislaus, Turlock, CA
Abstract
XRF analyses of sample 65A (northern), and 28M (southern) were performed by Washington State University. On a Cr-Y diagram, 28M (72 ppm Cr, 48 ppm Y) plots in the IAT field and is consistent with greater fractionation from the same parent that produced two of the dikes that cut the pillows. Sample 28M plots near the most evolved sheeted dikes from the WEO, but is distinct from the WEO pillows which plot in the MORB field. 65A (27 ppm Cr, 30 ppm Y) plots in the MORB field on a Cr-Y diagram, lies within a field defined by pillows from the WEO, but can't be related to 28M by fractionation. Ti-V ratios for both 28M (28) and 65A (36) are MORB-like, suggesting 28M is transitional, likely a back-arc basin basalt. The high FeO* (10.2 wt %) and TiO2 (2.1 wt%) in 65A is similar to some pillows in the western EO and the upper pillow sequence of the JO.