Factors determining the element concentration in sediments

For geochemical purposes, it is most convenient to give the rate of sedimentation, in units of weight per unit of area and time which can be called sedimentation intensity. The sedimentation intensity can be determined by means of formulae or a graph if the rate of sedimentation is stated in units of thickness per year and if the water content and the density of the sediment are also known. From the given weight percentages of an element in the sediment it is easy to calculate the sedimentation intensity of the element under consideration. An element can be transported to or away from the bottom, either in solution or in minerals carried in suspension. Assuming the chemical state to be more or less constant over a wide area or for a long period of time, the sedimentation intensity of an element may be divided by statistical methods into two components. The final concentration of the element in the sediment is determined by the content of the element in the minerals transported in suspension together with the element intensity of the chemically transported part. Thus it is possible to determine at least the direction of the chemical transport of the element. Three examples are discussed.