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UCL Home  /  Geography  /  Resources  /  Laboratory  /  Laboratory Methods  /  Lake Sediment Analysis  /  Wet Density

Wet Density

The density of the sediment is determined by its composition. In a sediment core variations in density down a core indicate fluctuations in sediment composition suggesting more than one sediment source. Sediment density is also required for calculations of sediment accumulation rate if the core is to be dated.

Equipment

The density of the wet sediment is measured using a 2cm3 capacity brass phial and a balance weighing to 4 decimal places. You will also need a fine metal spatula.

Procedure

The clean phial is weighed empty to 4 decimal places and then carefully filled with wet sediment. Any air bubbles are removed by tapping the base of the phial on a firm surface and the surface of the sediment is then smoothed to be level with the top edge of the phial. The phial is then re-weighed and the weight of the sediment divided by 2 to determine the density as grams per cm3. Replicate measurements on one sample can be carried out to assess the consistency of the analyst. The sediment may then be used for dry weight or loss on ignition analyses, or returned to the original sample, in which case care should be taken to avoid contamination with other samples. The phial is carefully washed and dried before measuring the next sample.