Surface nuclear magnetic resonance (SNMR) is a geophysical technique that has proved to be a useful tool for the investigation of hydrological properties of aquifers (porosity φ, saturated hydraulic conductivity k f ) in the past 10–15 years. Until recently, laboratory NMR has focused on consolidated sediments. In this research, an attempt is made to investigate unconsolidated sediments. To enable anenhanced understanding and interpretation of SNMR data, laboratory nuclear magnetic resonance (NMR) properties of synthetic and natural unconsolidated samples (glass beads, sand mixtures, bore-core samples from a Quaternary environment west of Berlin (Germany) and coarse sand samples with a varying clay content) were analysed. To verify the NMR measurements, pore-space properties (specific surface, porosity, pore-size distribution) were analysed. Finally, hydraulic conductivity measurements were conducted to verify both the hydraulic conductivity derived from NMR relaxation times and the hydraulic conductivity estimates based on grain size. The laboratory data were compared to SNMR field data to assess scaling effects due to the dispersion of relaxation. The results show that the relationship used to obtain hydraulic conductivity from NMR relaxation is suitable for predicting the saturated hydraulic conductivity of samples composed of clay, silt and coarse sand. Furthermore, it is found that the predictions of hydraulic conductivity of intermediate grain sizes with differing clay content vary over a wide range. A more individual approach with regard to the paramagnetic properties of the material might be needed to achieve successful estimations. Clay (because of its high specific surface and large surface-to-pore-volume ( S/V ) ratio) has a strong influence on NMR relaxation and the associated saturated hydraulic conductivity. The NMR relaxation of a series of coarse sand samples ( d =1.0–0.5 mm) with a clay content in the range 3–20% shows an exponential decay for the hydraulic conductivity.
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