Borehole Optical Stratigraphy and Neutron Scattering Density Measurements at Summit, Greenland

We have made side-by-side measurements in several boreholes at Summit, Greenland, using Borehole Optical Stratigraphy (BOS) and Neutron-Scattering density logging techniques. The BOS logs show a high degree of correlation at shallow depths with Neutron Scattering logs taken in the same borehole. This supports the hypothesis that BOS is detecting changes in both density and grain size, as well as possibly other parameters. The correlation between returned brightness and density decreases with depth and finally becomes negative, and we investigate the possible reasons for this inversion, which may be related to changes in densification regime from grain-boundary sliding to pressure sintering.