Geochemical data as indicators of palaeosalinity in coastal organic-rich sediments

A geochemical study of extractable major, minor and trace elements, peatlands from E Spain elucidated variations in salinity related to the interpretation of relative sea-level change. Samples were taken from different peatlands from the subsiding Valencia–Castellón quaternary basin (E Spain). These correspond to back-barrier marshes with brackish and freshwater influence containing Carex, Juncus, Typha and Phragmites. Samples from a highland Sphagnum moss freshwater peat-bog were also included for comparison. This paper categorizes palaeosalinity indicators in this coastal peat deposits as follows: B>Br≈I≈Na>S>>Ge>U. This compares with low rank coal which shows the following relationship: B>>Br>I>S>Na>Ge>U. The formulation of an index for characterising the organic/detrital content using K or Al concentration is also proposed. This resulted in the following salinity index, for peat: B/K>Br/K≈I/K≈Na/K>S/K>>Ge/K>U/K, and for low rank coal: B/K>>Br/K>I/K>S/K>Na/K>Ge/K>U/K.