Hyperspectral imaging in sedimentary rocks at core and outcrop scale

Full characterization of drill core and outcrops is time-consuming and requires multiple analytical techniques. Hyperspectral imaging can provide high-resolution spectra that may be interrogated for continuous mineralogical data, total organic carbon, and crystal size, to aid in strategizing an effective approach to sampling. Shortwave infrared (SWIR - 1 to 2.4 µm) and longwave (LWIR; 8 to12 µm) spectral imagery of shale drill core at a sub-millimeter per pixel scale reveals previously undetected trace fossils and sedimentary structures as well as distinct populations of amorphous and crystalline silica. Hyperspectral imaging can also be performed on outcrops and cliff faces, and is particularly useful in highlighting diagenetic phases in carbonates, where mimetic replacement and a lack of colour variation between mineral phases can result in an incomplete assessment of paragenesis. In an example of Cambrian dolomites from Western Canada, SWIR is used on an outcrop almost entirely composed of dolomite to detect individual phases, based on composition and crystal size.