An integrated micro‐computed tomography and thin‐section method for quantitative three‐dimensional analysis of unconsolidated sediments

Abstract

The systematic application of x‐ray micro‐computed tomography ( μ CT) and conventional thin‐section micromorphology to unconsolidated sediments remains challenging, as existing sample preparation methods are largely limited to thin‐section production. We present an integrated μ CT and thin‐section method based on a newly designed 3D‐printed subsampler that (1) enables precise extraction of areas of interest from soft sediment cores, (2) stabilizes unconsolidated wet sediments during μ CT scanning, and (3) allows dehydration and resin impregnation within the subsampler, thereby minimizing sediment disturbance prior to thin‐section preparation. The method was applied to sediment cores from lakes in Alaska and Chile. Two subsamples (8.0 × 1.5 × 1.5 cm; L × W × H), representing distinct depositional environments, were analyzed using high‐resolution μ CT and thin‐section micromorphology. Thin‐section analysis, although limited to two dimensions, provides highly detailed characterization of sediment texture and composition at the grain scale. μ CT yields complementary three‐dimensional (3D) information on the geometry, distribution, and orientation of sedimentary features, enabling quantitative analysis at resolutions comparable to those of thin sections. A key advantage of this approach is the direct comparability of datasets obtained from both techniques. This integrated μ CT and thin‐section method enables high‐resolution 3D analysis of sediment microstructures, providing new insights into sedimentary processes across a wide range of depositional environments and allowing quantitative comparisons among sedimentological studies.