MULTI-SCALE MAPPING OF THE METAMORPHIC MINERALOGY OF EDWARDS, TRAINWRECK, SNAKE, AND DEKALB OUTCROPS (ADIRONDACK REGION) USING THERMAL INFRARED, SEM, XRD AND PETROGRAPHIC TECHNIQUES

Progressive metamorphism in the Adirondack region of New York state has produced wide-ranging mineralogy which can vary greatly from outcrop to outcrop. We present here a multi-scale field-based and laboratory-based approach for characterizing the composition and distribution of minerals within four outcrops in the central Adirondacks: Edwards, Trainwreck, Snake, and DeKalb. High-resolution imagery has been collected of each outcrop using a GigaPan, a portable, tripod-mounted robotic instrument which collects hundreds of individual photos at high resolution, from which zoomable panoramic images can be created. Thermal infrared (TIR) imagery was also collected at each outcrop using a FLIR thermal camera, the broadband (7.5-13 μm) wavelength range of which has been divided into six individual wavelengths using external diffraction filters. These filters make the camera capable of collecting both temperature and compositional data, by producing a TIR spectrum of each pixel in the collected image, which can be used to map outcrop composition. TIR spectroscopy has proven to be a useful technique for quickly and efficiently gathering information about the temperature, surface texture, and surface composition/ mineralogy of a target. Many minerals have unique spectral features in the TIR, and can thus be distinguished from one another. We present here the initial results from this multi-scale analysis, and show that this combination of techniques has promise for characterizing mineralogical variability within outcrops. GigaPan imagery has been used as a reference for analyzing the TIR imagery collected at the outcrops. FLIR imagery results have been compared to results from thin section, XRD and SEM analyses of hand samples collected at each outcrop in order to characterize outcrop mineralogy at varying scales. XRD analyses identified common minerals that exist in all outcrops, like quartz and muscovite, and others specific to outcrops, like diopside and anorthite. From XRD results, we have concluded that there is no calcite present in these outcrops but instead they are dominantly composed of wollastonite or dolomite. Minerals that were visible at the outcrop but that didn’t exist in high enough abundance to show in XRD analysis have been resolved through SEM analysis of thin sections.