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K/T GeoServices,Inc. <br /> XRD3 -Bulk and Clay(<4 micron)XRD Analysis <br /> Sample Preparation and Analytical Procedures <br /> (Copyright 2019 K/T GeoServices,Inc.) <br /> Sample Preparation <br /> Samples submitted for bulk and clay mineral XRD analyses are cleaned of obvious contaminants <br /> and disaggregated in a mortar and pestle. A split of the sample is then transferred to distilled <br /> water and pulverized using a McCrone micronizing mill. The resultant powder is dried, <br /> disaggregated, and packed into a metal sample holder to produce random bulk mounts. A <br /> separate split of each sample is dispersed in distilled water using a sonic probe. The suspensions <br /> are size fractionated with a centrifuge to isolate <4 micron particles (<4 micron equivalent <br /> spherical diameter). The <4 micron suspensions are vacuum deposited on nylon membrane <br /> filters to produce oriented clay mineral mounts. <br /> Analytical Procedures <br /> X-ray Diffraction (XRD) analyses of the samples are performed using a Siemens D500 <br /> automated powder diffractometer equipped with a copper X-ray source (40kV, 30mA) and a <br /> scintillation X-ray detector. The bulk powder samples are analyzed over an angular range of five <br /> to sixty degrees two theta at a scan rate of one degree per minute. The oriented clay mounts are <br /> analyzed over an angular range of two to thirty six degrees two theta at a scan rate of one degree <br /> per minute. Data are first collected on the air dried clay mounts. Next, the clay mounts are <br /> exposed to ethylene glycol vapor for a minimum of 12 hours and data are collected again. <br /> XRD patterns from air-dried and glycol-solvated clay-fraction samples are compared and <br /> qualitatively analyzed to determine the types of clays present in the samples. Determinations of <br /> mixed-layer clay ordering and expandability are done by comparing experimental diffraction <br /> data from the glycol-solvated clay mounts with simulated one dimensional diffraction profiles <br /> generated using the program NEWMOD written by R. C. Reynolds. <br /> Semiquantitative determinations of bulk powder mineral amounts are done using Jade Software <br /> (Materials Data, Inc.) with the Whole Pattern Fitting option. All quantitative data (including <br /> clay mineral amounts) come from the bulk powder pattern. This is done by using Whole Pattern <br /> Fitting (WPF) and Rietveld refinement methods on the observed data. A diffraction model is fit <br /> to the measured pattern by non-linear least-square optimization in which certain parameters are <br /> varied to improve the fit of the model to the observed data. Modeling parameters include <br /> background, profile parameters, and lattice constants. For Rietveld refinement, a complete <br /> physics simulation is generally used in which crystal structures of the phases are required. Since <br /> the physics of scattering is well known,this method can be very exact and even allow adjustment <br /> of atomic coordinates, occupancies, and thermal parameters. <br /> K/T GeoServices Report Z23032 Page 6 of 10 February 17,2023 <br />