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Historic Properties Treatment Plan, Collom Mine, Colorado 43 <br />0 5.3.4 Radiocarbon Analysis <br />Samples collected from features during testing will be submitted to Beta Analytic, Inc. for <br />radiometric analysis. The samples may include wood charcoal, bone collagen samples, or bulk <br />soil samples. Smaller samples will be analyzed using accelerated mass spectrometry (AMS) <br />techniques. Radiocarbon age estimates are calibrated using the University of Washington <br />Quaternary Isotope Lab Radiocarbon Calibration Program (Version 1.3). <br />5.3.5 Obsidian Source Analysis <br />X -ray fluorescence will be employed on obsidian artifacts, if recovered, to determine the <br />material's origin. X -ray fluorescence analysis is a highly accurate scientific technique for <br />sourcing obsidian. Samples will be sent to Dr. Richard Hughes at the Geochemical Research <br />Laboratory in Portola Valley, California. <br />io 5.3.6 Plant Macrofossil Analysis <br />Flotation processing will be done using a Flote -Tech flotation system. This device is designed <br />to quickly process soil for the purpose of recovering floral, faunal, and artifactual materials. Its <br />dual water reservoirs house approximately 50 gallons of water that are filtered and recycled <br />through the system so that multiple samples can be run using the same water, thus conserving <br />water. Soil samples, up to 20 liters in size, are placed in a metal box with a "window mesh" <br />(1/16 -inch) bottom. The box is placed within the first reservoir, where the sample is agitated <br />by water jets forced upward under pressure through the soil sample. This forces lighter <br />materials to float to the surface where they are carried over the fabric filter. The water is then <br />housed in the second reservoir until the process repeats itself. The heavy fraction remains on <br />the 1/16 -inch mesh, where it is collected by inverting, and the fine mesh containing the light <br />fraction is also removed. The entire process takes approximately 5 to 15 minutes, depending <br />on the clay content of the soil. After processing, both the heavy fraction and the light fraction <br />47599 TRC Mariah Associates Inc. <br />