MULTI-SCALE MAPPING OF THE METAMORPHIC MINERALOGY OF POPPLE HILL, STEER'S HEAD, AND ANTWERP OUTCROPS (ADIRONDACK REGION) USING THERMAL INFRARED, SEM, XRD, AND PETROGRAPHIC TECHNIQUES

Multi-scale analysis of the mineralogical compositions of three outcrops located near Gouverneur, New York (Popple Hill, Steer’s Head, and Antwerp) was performed using various field-based and laboratory-based techniques. Although a relatively short distance from one another, these three metamorphic outcrops display significantly different mineralogies. The Popple Hill Gneiss is a highly deformed migmatite composed of thickly banded gneiss, amphibolite and leucosome with abundant folds, veins and boudins. In contrast, the Steer’s Head outcrop is composed of marble surrounded by gray to pink granitic gneiss with large gneiss intrusions within the marble. Similar to Popple Hill, the Antwerp outcrop is composed of amphibolite and gneiss with thin veins of pegmatite. High-resolution imagery was collected at each outcrop using a GigaPan, a robotic, tripod-mounted instrument capable of collecting high-resolution panoramic images. These panoramic images allow in-depth analyses of outcrop textures and assist in mineral identification. In addition, a FLIR thermal camera with a broadband (7.5-13 μm) wavelength range and seven diffraction filters was used to collect thermal infrared (TIR) imagery at each outcrop. Using these filters, individual minerals were identified due to their distinct spectral features, and a compositional map of each outcrop was created. The GigaPan images taken at each outcrop have been used as a reference for analyzing the TIR imagery to verify mineralogical compositions. Additionally, petrological analyses were performed on thin sections of hand samples collected at each outcrop and SEM and XRD analyses on the hand samples allowed for identification of minerals and chemical signatures of the rocks. 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. We present here the results from this multi-scale analysis, and demonstrate the usefulness of this combination of techniques for characterizing variability in mineralogy within outcrops.