Electron Backscatter Diffraction has been largely used in the metallurgic and material sciences and until now, has found few applications in the forensic sciences. One of the few utilizations of this ...technique in forensic science is in firearm serial number restoration as a complementary technique to the time-consuming and tedious chemical etching methods. This research aims to expand the uses of Electron Backscatter Diffraction in the forensic sciences as it applies to other types of samples, specifically as it pertains to forensic mineral analysis. Electron Backscatter Diffraction offers the analyst information regarding crystal structure of a material, so long as the sample is crystalline in nature. Minerals, many of which are crystalline in nature, can be analyzed using Electron Backscatter Diffraction. The Electron Backscatter Diffraction instrumentation used to achieve these patterns is coupled with a Scanning Electron Microscope and Energy Dispersive X-ray Spectrometer. These three instruments provide the analyst information of morphology, elemental composition, and of course, crystal structure. This combination of information in one single system is the most attractive feature of this method.Minerals have long been encountered in items of forensic importance, primarily as the main constituent of the inorganic portion of soil. Scientists have determined numerous methods to analyze this type of evidence by its mineral content, to determine if two samples came from a common origin. This information can aid in a forensic investigation to determine if a suspect has ever been at a crime scene, or with the use of geo-sourcing, determine where a crime scene is located.Polymorphisms are of special importance in forensic science as they further allow the differentiation of samples based on their crystal structure. By many of the currently used forensic techniques for analyzing the mineral fraction of soil samples, only the chemical composition is determined, by the physical properties of the bulk sample assessed. However, with the use of Electron Backscatter Diffraction, one can determine the crystal structure and determine the polymorph present. Determining the crystal structure of a mineral can help to add to the information about a sample, either as exclusionary or inclusionary evidence in a forensic investigation. This study aims to examine minerals commonly found in nature, which could ultimately become forensic evidence, and the ability of Electron Backscatter Diffraction to obtain crystal information from a single grain or crystal. The parameters necessary to achieve this information will be thoroughly studied. Various sample preparation techniques will be considered. The applicability of this technique to gem authentication will be tested. Lastly, this research aims to answer the question as to whether Electron Backscatter Diffraction can be successfully used to analyze minerals in real forensic case samples.
Elemental quantification instruments for planetary missions provide a capability for in-situ identification of mineral phases via stoichiometry, an essential step in petrological investigations. ...X-ray fluorescence (XRF) has been employed for this purpose by multiple generations of Mars rovers (i.e., Pathfinder, Spirit and Opportunity, Curiosity and Perseverance). The Planetary Instrument for X-ray Lithochemistry (PIXL) aboard Perseverance rasters a micro-focused X-ray beam to generate micron-mm-sized maps illustrating variations in elemental composition and allowing mission scientists to identify rock components (i.e., sedimentary grains, veins and igneous crystals). Energy-dispersive X-ray diffraction can also be detected with PIXL and can be used as an additional constraint on component boundaries, providing PIXL with the capability to map monocrystalline regions in-situ. Here we introduce and apply a new method where each diffraction peak is partitioned independently according to its energy, using the instrument geometry to inform consistent partitioning. Applying this method to datasets acquired from the Dourbes abrasion patch in the Séítah formation of Jezero crater, Mars, reveals monocrystalline regions that were hidden using previous methods. This application of the technique allows faster and more accurate visualization of petrographic textures in future PIXL datasets, in particular those with rock components that are not easily separable using stoichiometry alone.
•X-ray diffraction peaks can be partitioned by energy using instrumental geometry.•Diffraction partitions can map monocrystalline regions.•Visualizing monocrystalline regions can reveal petrographic textures.•New monocrystalline region extents are observed in the Dourbes abrasion patch.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The differences in the composition of bead sets from the Filippovka I burial were analyzed by the author in order to determine regularities in their co-occurrence. The mineralogical analysis has ...revealed the glass beads made of olivine and fluorite. The mineralogical and technological study allowed to classify all beads according to manufacturing techniques. On the basis of the comparison with beads of the same age from India, Persia, Middle Asia, Northern Black Sea coast, the Caucasus, and the Pamir, possible production centers have been hypothesized. The results were compared with earlier published data on bead sets from the Southern Urals burials of the late 6th - early 3rd centuries B.C. The literature data on the timing of appearance and the origin of beads analogous to those from Filippovka barrows were also analyzed. The results suggest that the observed differences in the composition of bead sets reflect the appearance or disappearance of particular bead types in the region. The analysis of mutual occurrence of certain bead types allowed to allocate two groups of the sets which are smoothly replacing each other in time. This allowed the author to reconstruct the sequence of appearance of bead sets in the Filippovka I burial.
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