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Integrated Ocean Drilling Program (IODP) Expedition 341 was conducted to investigate the relationship among northwestern Cordilleran ice sheet glaciation, tectonic processes, and changes in regional and global paleoclimate (see the “Methods” chapter [Jaeger et al., 2014a]). IODP Sites U1420 and U1421 were drilled to sample sediments of the Pamplona zone, which is a fold and thrust belt that has accommodated shortening as a result of the underthrusting of the Yakutat terrane under North America (Worthington et al., 2010) (Fig. F1). Understanding the transport and deformation properties of these sediments and the factors that control them is a key component of understanding if and how loading through rapid sedimentation or glacial advance can alter the locus of deformation in tectonic wedges (e.g., Berger et al., 2008). This in turn provides key information to the Expedition 341 scientific goals.

We performed laboratory measurements of consolidation and fluid transport properties, as well as grain size, to constrain key properties of Pamplona zone sediments and understand the role that grain size plays in controlling these properties. We used whole-round samples for constant-rate-of-strain (CRS) consolidation experiments to determine permeability, compression index, and swelling index. We performed grain size measurements on trimmings from CRS specimens to compare with the measured geotechnical properties. Our results provide important information on properties of the sediments in the Pamplona zone, which may be used to understand the role between glaciation, sedimentation, and tectonic deformation.