Hardness index of bottom deposits
The hardness index, defined and illustrated below, may be used to compare the density of the upper part of sediment cores, as illustrated further down, and may also be used as an important parameter in the classification of lake- and sea bottoms.
Core 491 from the bay Nylandsfjärden. Downcore variation in content of solids, calculated from the recorded film density along the centerline of the radiograph of the upper part of core 491. The accumulated amount of solids down to a depth of 10 cm (in g/cm2) is used as a hardness index of the bottom. The radiographically calculated amount of solids (yr) down to a depth of 208 mm is 99.2 % of the amount found by drying and weighing the deposits (y1). From Axelsson 1983 (Hydrobiologia 103).
