Characterization and Proposal of a Substitute Stone for the Restoration of the Archaeological Site of Lixus (Larache, Morocco)

Abstract

The town of Lixus is the most important archaeological site on the Moroccan Atlantic coast. It is essentially built, from at least 12 centuries BC, by rocks of sedimentary origin. A preliminary diagnosis allowed us to identify the main factors of the physico-chemical degradation observed on the buildings of the monument. The interest of the conservation of this archaeological richness requires an intervention of safeguard, which will go beyond the operation of protection of its perimeter to another desired action of development of its tourist and cultural purposes. The objective of this work mainly concerns a comparative study of the petro-physical characteristics of the sandstones sampled at various levels of the geological formation located to the northwest of the Lixus site, as a substitute stone, which will be used for any eventual rehabilitation operation. On the basis of the definition of the main causes of pathologies observed at the level of the site, the realization of these categories of action are first carried out by an experimental simulation of accelerated aging by "imbibition-drying'' cycling. Then the call for petrographic analyzes where the thin sections revealed the mineralogical composition, the proportion of the figured elements and the nature of the bonding phase of the rocks tested; then the chemical characterization carried out by XRF fluorescence (X-Ray Fluorescence) and the quantification of the carbonated fraction by calcimetry. Also and with the help of geotechnical tests, in particular the determination of the porosity, the density and the hydric density as well as the uniaxial compressive strength (RC) and the rebound index (hardness by sclerometer). The confrontation of all the results obtained reveal a valid estimate of the potential for durability and compatibility in the sense of homogeneity with the material to be replaced, in view of their significant mineralogical composition in terms of sufficient quantity of silica and calcite. The tests used allowed the refinement of the discriminating mechanical parameters, they highlighted the relationships between the mechanical resistance and the physical properties of this replacement stone, particularly the high mechanical resistance (50.1-74.9 MPa), the absolute density values (2.54-2.68) and the rebound index (30-34) significant, which evolve inversely proportional to the low porosity values (1.7-2.20). However, all these recorded results have qualified this rock as a resistant lithology according to the classification adopted by the International Society of Rock Mechanics (ISRM), recommended for any possible renovation of Lixus.

Diachronic Study of the North Atlantic Coast of Morocco between Larache and Moulay Bousselham: A Geometric Approach

“…The Lower Loukkos complex or Larache marshes consist of a variety of environments, including an estuarine area, shallow waters along the seashore, salt meadows, freshwater ponds, floodplains, and several abandoned salt pans. The estuary of the Loukkos River extends to the guard dam erected to prevent the tide from reaching agricultural lands (Laouina, 2010) and (Chahid, 2022). The estuarine area of the Loukkos River and the former salt pans extend upstream, near the lower course of the Loukkos, including the reservoir formed by the guard dam.…”