Abstract
Lagoonal systems are vulnerable environments in the present day context of global climate change. The study of their sedimentary infill is critical to understand marine and continental factors controlling their evolution, and in so doing, evaluate their future behaviour and potential management. In that context, Mediterranean lagoons are particularly important due to their social and economic values. The Nador lagoon, located along the Western Mediterranean coast, is the largest Moroccan lagoon. In order to study its sedimentary infill, very high-resolution seismic reflection data were acquired, providing for the first time an image of the architecture of the infilling Holocene deposits. The combination between sediment core information and seismic data allows the reconstruction of the lagoon history over the last millennium. We demonstrate that the time between the 15th and 19th century has been a key period in the lagoon evolution. Sand bodies of marine origin dominated the sedimentary infill of the lagoon during that time. We propose that this stage of the Nador lagoon, the evolution and infilling is closely linked both to the local tectonic and Little Ice Age climatic contexts. These results are important to understand the mode of evolution of other comparable lagoons along microtidal coasts.