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Identification of organic residues (depicted in blue) on the projectile points from the summit of Tigre pyramid. (Photo: R.D. Hansen). PXRF Analyses of Obsidian, BYU Laboratories During the 2013 season, PXRF analyses were conducted on points from the summit of Tigre pyramid at the Geology and Geochemistry laboratories at Brigham Young University. The study was conducted by BYU Geo-lab technician Aubrey Longhurst, under the supervision of BYU Professor of Geochemistry, Dr. Steven Nelson. The study did detect sharp elemental distinctions in the points, which will allow positive identification of the sources of the obsidian. Analyst Fred Nelson at BYU had previously conducted XRF studies for Dr. Hansen, and discovered that all of the obsidian recovered on the summit of Tigre pyramid had sources from Highland Mexico, including the obsidian sources at Pachuca, Otumba, Paredon, and Zaragoza. It is believed that the remainder of the several hundred points will demonstrate a similar sourcing.