Sedimentological record of a river mouth in Northern Lebanon during the Holocene

Within the framework of a geoarchaeological project to reconstruct the environmental conditions in the hinterland of an archaeological excavation in Northern Lebanon a drilling core near to the Nahr-El-Jaouz river mouth was taken in 2022. The core exhibits a 10,50m thick succession of Holocene fluvial deposits. Sampling comprised more than 100 samples. Sedimentological techniques using grain size distributions and textural parameters were applied for the assessment of facies type and the conditions of sediment transport and deposition.

At a drilled depth of 10,00-10,50m gravelly sediments occurred representing the deltaic foreset followed by an alternating sequence of muds and sandy muds deposited directly at the river mouth or somewhat upstream (deltaic topset). The section above consisting of sandy to muddy sediments was formed by temporarily floods or stagnant water showing mainly suspension transport of the particles. The facial interpretation indicates a transition between a lagoonal environment of the topset and a distal floodplain far from the main river.

Most of the upper core (9,35m to the surface) shows sediments formed within a wetland environment. Frequent facial changes from distal to proximate floodplain positions with muddy and sandy deposits can be observed. Gravelly layers occur as occasional intercalations deposited by more turbulent floods of different reach and force.

The drill core indicates a former sea arm of several kilometres in length for the Nahr-El-Jaouz river mouth. Unfortunately, at present no age data from ¹⁴C analyses of taken charcoals or from OSL dating are available. These analyses are still in progress.