An Eocene tidal inlet/washover type barrier island complex in the south Pyrenean marginal basin

Several harrier island sand bodies are well exposed in the southern Pyrenees, Spain. They belong to the Pano Formation of Lutetian (Upper Eocene) age and were formed in an environment which was strongly influenced by rising sea level. A detailed sedimentological study of a calcarenitic sediment body in this Formation is presented.
The larger part of the harrier system described here is made up of tidal inlet deposits and washover sequences. The sediment body has a lense-shaped geometry: The width of the exposed body is 260 m and its maximum thickness is 20 m. It is made up of thin to thick bedded calcarenites. The tidal inlet part consists of massive, and tabular to lense-shaped beds. Laterally, in a landward direction, massive beds alternate with thinner washover beds, which have a primary landward directed dip. The marl/sand ratio increases in this direction.
In their proximal parts, washover beds are subdivided by horizontal erosional surfaces. The subdivision shows a regular pattern and is attributed to varying storm intensities during one single storm event. Vertical stacking of tidal inlet and washover deposits is ascribed to a balance between the amount of sediment deposited and the rate of relative rise of sea level.