Non-destructive multi-sensor core logging allows rapid imaging, measurement of bulk density and estimation of ice content in permafrost cores

Abstract. Permafrost cores provide physical samples that can be used to measure the characteristics of frozen ground. Measurement of core physical properties, however, are typically destructive and time intensive. In this study, multi-sensor core logging (MSCL) is used to provide a rapid, high-resolution, non-destructive method to image and collect the physical properties of permafrost cores, allowing the visualization of cryostructures, measurement of bulk density and magnetic susceptibility, and estimation of volumetric ice content. Six permafrost cores with differing properties were analyzed using MSCL and compared with established destructive analyses to assess the potential of this instrument both in terms of accuracy and relative rate of data acquisition. A calibration procedure is presented for gamma ray attenuation from a ¹³⁷Cs source that is specific to frozen core materials. This accurately measures bulk density over the wide range of material densities found in permafrost. MSCL bulk density data show strong agreement with destructive analyses based on discrete sample measurements. Bulk density data from the gamma attenuation, along with soil density measurements for different sediment types, are used to estimate volumetric ice content. The results show strong agreement with destructive analyses, illustrating that MSCL can provide accurate non-destructive estimates of ice contents and provide a digital archive of permafrost cores for future applications.