Sedimentology and depositional history of the Claret Formation (‘carse clay’) at Bothkennar, near Grangemouth

Abstract

Synopsis The estuarine sediments of Flandrian age which comprise the Claret Formation in the Bothkennar area can be divided into bedded, mottled and laminated facies on the basis of primary sedimentary structures, frequency of silty laminae and the nature and extent of bioturbation. The mottled facies can be further subdivided by the style of bioturbation. The facies are very similar in overall particle size distribution and mineralogy. Biogenic traces occur in all the facies and have been tentatively matched to organisms present in the modern infauna Equation ()of the Firth of Forth. The succession of facies has been controlled by the fall of relative sea-level since the Flandrian maximum and records an emergent sequence from sub-tidal (probable water depth around 20 m) to inter-tidal. In the Bothkennar area four local subdivisions can be recognized in the Claret Formation, which reflect changes in sedimentary environment consequent on the reduction in water depth.