The salinity facies of the Keuper sediments on the basis of the determination of boron content
The boron concentration of illites from sediments of the German Keuper Basin has been investigated in order to define palaeosalinity. The regional boron distribution of the Schilfsandstein and Lettenkeupersandstein Formations which have been sedimented in great lateral uniformity plainly corresponds with the current directions evaluated from cross-bedding measurements. Short-time variations of palaeosalinity during the Gipskeuper Formation have no effect on boron concentration, thus confirming the laboratory experiments of the installation of boron in illites which indicated that considerable time is required for establishing the boron- illite equilibrium. The present investigations show that boron in illites can be success- fully applied to regional problems provided that close consideration is given to the mineralogical composition of the sediment.