RESEARCH METHOD
Grain size & sedimentology
Sediment texture, transport and depositional change.
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What the method shows
Sediment texture and its variation among layers and through a profile.
How we use it in HEL
At Wenceslas Square and Mikulčice, grain size forms part of the multi-proxy interpretation of soil–sediment processes and Dark Earth.
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How the method works
Grain-size analysis measures the proportion of particles across size classes. Depending on the material it may use sieving, settling methods or laser diffraction, producing a distribution rather than a single value.
Distribution changes can reflect sediment source, transport energy and depositional mode, but also later pedogenesis, bioturbation and human reworking. In urban and settlement deposits we therefore use grain size mainly within a multi-proxy reconstruction of formation processes.
Similar distributions may arise from different processes, and one process may produce several textures. Stratigraphic position and independent proxies are therefore essential.
micromorphology, geochemistry, magnetic susceptibility and detailed sediment description.
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In practice
- Input / materialbulk soil or sediment sample
- Scale / resolutionsample / layer and profile-scale trends
- Sampling / preparationrepresentative material from defined stratigraphic units
- Typical outputgrain-size distributions and textural comparisons
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Limits and control
Grain size alone does not determine layer origin; in HEL it is read together with stratigraphy, geochemistry and other proxies.
Wenceslas Square, Mikulčice-Valy
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References and HEL studies
Selected studies underpinning the method descriptions and examples used by Human Earth Lab.