Search

International audience

International audience

International audience; In a context of overexploitation of the karst system of the Middle Atlas Causses feeding the Saïs basin and the current climatic variations, the study of circulations and of renewal of waters of this system in the Fes-Meknes area becomes essential for the population, in order to maintain a sufficient quality of waters with a good management.By coupling hydrochemical and isotopic analysis methods (delta-D, delta O-18, Radon-222), saturation indices obtained from PHREEQC code and principal component analysis (PCA) of ten springs and three wells, a first conceptual model of groundwater flows of this karst system was obtained . These waters are mainly renewed by the rainfall of L'Hajeb Causse and secondarly by the rainfall of Guigo Causse containing several springs. Hydrochemistry and saturation indexes allowed us to highlight two types of waters: a main contribution of Liasic origin and two low contributions of Triassic origin at the southern extremities (SE, SW) of the basin. We pointed out the existence of five local recharge zones of different altitudes (900 to 1500 m asl.) including the two main mixing zones to the south (SE, SW). Radon-222 showed areas of rapid exchange (upwelling time less than two weeks) between waters of Liasic aquifer and the ones of Triassic origin with high radon activity.The use of PCA on hydrochemical data, allowed us to refine the kind of waters, their transit times and highlighted the existence of several mixing zones between the Triassic aquitard and the Liasic aquifers in more or less faulted structures for the two causses. Our results allow us to obtain a first conceptual model of groundwater circulations between the two causses and the Saïs basin.Previous campaigns of electrical resistivity tomography coupled with electromagnetic measurements (EM34) revealed lateral and vertical variations of electrical conductivity changing with the depth along the North-South axis, and a preferential drain perpendicularly to the causses (EGU 2009). We can note that groundwater flows are conditioned by two major fracture networks, NE-SW and NW-SE directions (Bentayeb & Leclerc 1977, Amraoui 2005). A karstic complex water circulation is especially developed locally at the border of the two hydrogeological units (Qarqori 2015).

International audience

Two profiles were taken on two cultivated soils (a calcareous soil and a vertisol) irrigated by the wastewater in the Ourzirha area (NE of the Meknes city), to explain the variability of the contents of Trace Elements (TE), their principal associations, and to predict their origins in these soils. To the whole of the geochemical data, a multivariate statistical analysis was applied (PCA and HAC). The results showed that the contents raised on the profiles are of lithogenic origin mainly, with a notable contribution of the exogenic contributions on the surface. These exogenic contributions on the surface are very large for the Zn on the vertisol.

Most of Roman archaeological sites in Morocco contain many mosaics, it offers significant pavements decorated with the majority of architectural buildings components different archaeological sites of Morocco. Petrographic and mineralogical analyses of tesserae coming from some of Roman mosaics in Volubilis, and Lixus, archaeological sites have revealed the petrographic nature of the rocks used in the decoration of different tessellata. The knowledge of petrographical characteristics of these tesserae represents an essential step to understand mechanical properties of the used materials, their weathering processes and the location of their origin. This comparative study carried on natural materials used in roman mosaics tesselata in some archaeological sites give us ideas about the provenance of building materials and the movement of materials in Morocco and in the Mediterranean region. This study will also provide solutions to guide professionals in the choice of interventions related to the restoration and conservation., Fas’ta yer alan Roma Dönemi’ne ait arkeolojik alanların büyük bir kısmı pek çok mozaik barındırmaktadır. Fas’ta yer alan pek çok farklı arkeolojik alanda, üzerinde mimari yapı bileşenlerinin betimlendiği dikkate değer mozaikler görülmektedir. Volubilis ve Lixus’taki Roma Dönemi’ne ait bazı mozaiklerden alınan tessera örneklerinin petrografik ve mineralojik analizi ile mozaikler üzerinde kullanılan farklı kayaç türleri belirlenmiştir. Tesseraların üretildiği kayaç türlerinin belirlenmesi, materyaller üzerinde kullanılan teknik, ufalanma süreçleri ve kaynaklarının belirlenmesiyle ilgili olarak önemli bir adımdır. Roma mozaiklerinden alınan doğal örnekler üzerinden karşılaştırmalı bir çalışma gerçekleştirilmesiyle yapılarda kullanılan hammadde kaynakları ile hammaddelerin Fas ve Akdeniz’deki yayılımları hakkında fikirler edinilmiştir. Bu çalışma aynı zamanda profesyoneller için restorasyon ve konservasyon esnasında uygulanacak olan müdahalelerle ilgili çözüm önerileri getiren bir rehber niteliği taşımaktadır.

Roman mosaics in Volubilis are opus tessellatum type. They show different deterioration features represented by the lacunae formation (lack of tesserae) and break down of mosaic pavements by fracturing. The deterioration of the tessellatum and the formation of cracks are related to the swelling of soil supporting these mosaics. Furthermore, the tessellatum is also damaged by chemical dissolution of the fine grained-mortar between (lime and quartz fine grain) and under tesserae, giving an important porosity and making the tessellatum very easy to collapse. A part from limestone tesserae, which show formation of vesicles by chemical dissolution, other ones such as marble and glass tesserae appear to be resistant to the weathering action., Volublis’deki Roma mozaikleri opus tessellatum tipindedir. Bu mozaikler, Lacunae düzeninde (tesserae eksikliği) belirtilenden farklı bir bozulma özelliği göstermekte olup mozaik döşemeleri çatlaklarla ve kırılmalarla bozu- lur. Tessellatum’un bozulması ve çatlakların düzeni mozaiği taşıyan topraktaki kabarmalarla ilişkilidir. Ayrıca, döşeme tesserae aralarında ve altında bulunan ve onlara önemli derecede gözeneklilik veren ve tessellatumun kolayca çökmesine sebep olan ince taneli harçtaki (ince taneli kireç ve kuvars) kimyasal bozulmalar nedeniyle de zarar görebilir. Kimyasal çözünmeden dolayı kabarcık oluşumu gösteren kireçtaşı tesseranın dışında, mer- mer ve cam tesseralar kötü havadan aşınmalara karşı direnç göstermektedir

This study focusses on the development and application of an innovative protocol which combines chemical data, GIS (geographical information system) and PCA, involving numeric (chemical composition) and categorical (typology of object, archaeological context, chronology and geographical areas) variables, as a simple tool to help in the visualisation and interpretation of large multidisciplinary datasets on Cu-based alloy archaeological artefacts influenced by Phoenician-Punic contacts. The protocol is a useful tool for highlighting existing connections between specific alloy chemical compositions, the location of the original settlement where the artefact had been produced and the proximity to mining resources, waterways, and allochthonous presence such as, in the specific case of this study, the Phoenician and Punic influence in the Iberian bronze production during the Late Bronze Age-Iron Age. The protocol was tested successfully in a case study concerning the precise dating and provenance of bronze statuettes of unknown age and provenance from the Evora Museum collection in Southern Portugal where it confirmed and further refined earlier hypotheses based solely on archaeological and/or chemical studies. The results were interpreted with a unique perspective, to validate the GIS system in combination with experimental chemical-physical data to yield the identification of metallurgical sites of bronze production.