Evolution tectono-sédimentaire et magmatique des bassins viséen supérieur d’Azrou-Khénifra et des Jebilet orientales (Meseta marocaine)

During Upper Visean times, the eastern mesetian basins of eastern Jebilet and Azrou Khenifra show great tectono-sedimentary and magmatic evolution similarities. Their deposits record large instabilities and disorganization with huge thickness and lithological variations, related to a synsedimentary tectonic context. At the same time, tilted block tectonics affect the basement of these basins, controlled by bordering transfert faults. Basic dominant magmatic bodies set up in these basins. Their continental alkaline chemical characteristics are consistent with the regional geodynamic context in this area. Initiated along the transitional zone between eastern and western Meseta, the Azrou-Khenifra and Jebilet basins correspond to intracontinental throws, initiated on and controlled by major strike-slip faults. Their evolution is most likely earlier in time and of a weak opening rate than the neighboring western Meseta basins.Au Viséen supérieur, les bassins mesetiens des Jebilet orientales et d’Azrou Khénifra montrent de grandes similitudes de leur évolution tectono-sédimentaire et magmatiques. Leurs dépôts enregistrent de grandes instabilités liées à une tectonique syn-sédimentaire responsable localement d’une intense désorganisation et de grandes variations de faciès et d’épaisseurs. Ces instabilités sont engendrées par une tectonique en blocs basculés qui affecte le substratum anté-Viséen, contrôlée par des accidents bordiers sub-verticaux à forte composante transcurrente. Des corps magmatiques, pour l’essentiel basiques, se mettent en place dans ces bassins. Ils présentent des caractères chimiques des séries magmatiques alcalines mise en place dans un contexte intracontinental et anorogénique. Initiés le long de la zone de transition entre la Meseta orientale et occidentale, les bassins d’Azrou-Khénifra et des Jebilet orientales correspondent à des sillons intracontinentaux, initiés et contrôlés par des décrochements. Leur évolution est sans doute plus précoce et montre un faible taux d’ouverture que celui enregistré dans les bassins adjacents de la meseta occidentale

Impact of climate change on forest resources: Case of Quercus rotundifolia, Tetraclinis articulata, Juniperus phoenicea, J. oxycedrus, J. thurifera and Pinus halepensis

Forest resources in the Ourika watershed are subject to several anthropogenic and climatic degradation factors. As for the human factor, this degradation of forest resources is explained by the bad practices exercised by the local population expressed by the cutting of live wood, carbonization, and overgrazing. In terms of the climatic factor, the decrease in the amount of rainfall and the increase in temperature contribute to the exacerbation of the degradation of these resources. In order to better understand the evolution of plant cover in a changing climate context, this study highlights an assessment of the impact of climate change on forest dynamics based on a process-based model at the forest landscape scale which makes it possible to simulate the changes according to growth, succession, disturbances (fire, wind, insects, etc), forest management, and land use change. This analysis is based on the use of the LANDIS-II model and the PnET-succession extension. Projections of the dynamics of forest communities are made using climate projections from the Japanese global circulation model adopted by Morocco (model for interdisciplinary research on climate – earth system models) and this by adopting the two climate scenarios , representative concentration pathways 4.5 and 8.5. The results obtained highlight the spatial distribution of the ecosystems studied after 100 years with a quantitative evaluation of the total average biomass of these resources as a function of climatic disturbances. In general, the estimated total biomass will decline over the coming years under the joint effect of the climate change and the aging of forest stands, while on the other hand, the distribution of potential areas for species settlement remains independent of the effect of these climate changes

Prevalence of oral behaviours in general dental patients attending a university clinic in Italy

Background: Oral behaviors represent a diverse array of habits beyond the physiological behaviors of the stomatognathic system. Objective: To describe the prevalence of different oral behaviors, as reported with the Oral Behavior Checklist (OBC-21), in a convenience sample of patients attending an Italian university clinic for routine dental cares. Methods: In this study, charts of adult patients presenting to the dental department of a regional hospital in Trieste, Italy, from January 2018 and January 2019 were reviewed. Patients with complete files were retrieved, and those with orofacial pain complaints were excluded. OBC-21 scores and grades (score of 0 corresponding to no risk, 1-24 to low risk, and higher than 24 to high risk) were analyzed and stratified according to age and sex. Results: Data from a total of 1424 patients were reported. The overall mean OBC score was 13.3 ± 9.9, with 6.7% no-risk grade, 79.6% low-risk grade, and 13.7% high-risk grade. In general, mean OBC scores decreased with increasing age. Females showed a higher frequency of high-risk grade than males. Most frequent prevalent habits included yawning (73.1%), eating between meals (66.9%) and chewing food on one side only (63.3%). Other behaviors were also highly prevalent, including pressing, touching, or holding teeth together other than while eating (52.7%) and awake clenching (47.5%). Conclusion: A low-risk grade of oral behaviors has been found to be frequent in our sample. Future studies are warranted to confirm these findings in larger, representative general populations and to assess if any of these habits are linked to negative effects on the stomatognathic system

Composition chimique et activité antimicrobienne des huiles essentielles de Thymus algeriensis Boiss. & Reut. et Thymus ciliatus (Desf.) Benth. du Maroc

Chemical composition and antimicrobial activity of the Thymus algeriensis Boiss. & Reut. and Thymus ciliatus (Desf.) Benth. essential oils of Morocco. The aim of this work is to study the chemical composition and antibacterial and antifungal activity of essential oils of Thymus algeriensis Boiss. & Reut. and Thymus ciliatus (Desf.) Benth. of Morocco against seven microorganisms. The essential oils of T. ciliatus are characterized by the presence of thymol (44.2%), β-E-ocimene (25.8%) and α-terpinene (12.3%) as principal chemical components. The essential oils of T. algeriensis are formed mainly by camphor (27.7%) and α-pinene (20.5%). The oil of T. ciliatus showed a strong antibacterial and antifungal activity against all tested bacteria and fungi. This bioactivity is due mainly to the richness of this essential oil in thymol known for its effectiveness against the microbial agents

[Geochemical features and tectonic setting of Late Neoproterozoic Vendian volcanism in the western High Atlas, Morocco]

Late Neoproterozoic Vendian volcanic and volcaniclastic rocks are widely distributed in the western High Atlas. They are located north of the Tizi n'Test Fault, separating the West African Craton from a northerly adjacent craton. These volcanic rocks overlie a sernipelitic formation, which represents the equivalent of the Tidilline and Anzi Formations,of the Anti-Atlas. The geochemical characteristics of these volcanic rocks' suggest a calc-alkaline active margin environment associated with the post Pan-African tectonics. They differ from those of the Anti-Atlas by their lower content of K2O. The later rock type was generated by a melting process of the crust subducted beneath the northern craton. A carbonate-shale unit, which contains examples of interstratified calc-alkaline dacite, overlies the volcanic succession, demonstrating that the volcanic activity continued sporadically until Early Cambrian times. (C) 2002 Elsevier Science Limited. All rights reserved

U-Pb Zircon geochronological and petrologic constraints on the post-collisional Variscan volcanism of the Tiddas-Souk Es-Sebt des Aït Ikko (Tsesdai) basin (Western Meseta, Morocco)

Trabajo presentado en el 2nd International Congress on Permian and Triassic, celebrado en Casablanca (Marruecos), del 24 al 27 de abril de 2018The NE-SW Tsesdai basin (110 km to the SE of Rabat) is the third largest Late Palaeozoic continental trough in the northern Central Moroccan Meseta. It is <20 km long and ~2-3 km wide, comprising mixed volcano-sedimentary reddish-purple Permian rocks that rest on Visean deep marine siliciclastic sediments, overlain by the Triassic and Cenozoic formations. The lower and upper boundaries correspond to angular unconformities. The Permian age of these formations was obtained with the help of plant remains and vertebrate ichnofossils (e.g., Voigt et al., 2011, etc.). The occurrence of volcanics in this basin was first reported by Termier (1936) who considered them (as well as those in Khenifra) as forming the “Central Moroccan volcanic axis” stretching from Khenifra to Tiddas and displaying felsic and mafic volcanics emplaced in the Neogene/Quaternary. This “axial-model” has been accepted by several authors (e.g. Michard, 1976) until the 1980s. Later contributions largely improved the geological knowledge of this basin (e.g., Gonord et al.,1980; Cailleux et al., 1983; Zouine, 1986; etc.). The conclusions of these authors are:(i) the volcanic complex is Permian s.l. (post-Carboniferous and pre-Triassic, presumably Stephanian/Permian) a percept based on (a) the intrusion of rhyolites into the Visean deep marine siliciclastics of the basement (shark-fin rhyolitic dome of Ari el Mahsar extrusive and its satellite dykes); (b) the angular unconformity between the red detritic sediments and the Visean siliciclastics folded during the late Westphalian A; (c) the presence of reworked rhyolitic/andesitic pebbles in the red sediments of the Tsesdai basin and their absence in the detrital sediments of the Westphalian C/ D preserved nearby in the Sidi Kacem graben; (d) the angular unconformity between the Triassic and the red detritals; and (d) strike-slip fault that postdates the basin sedimentary/volcanic formations and predates the Triassic/Cenozoic. (ii) the distinction of 3 major volcanic pulses: the first one (mainly andesitic) predates the Permian series; witnesses of this pulse can still be observed in Tiddas, but most material is reworked in the conglomerates; the second pulse is synsedimentary, displays different petrographic characteristics, and it is remarkable for its andesitic lava flows interbedded with the detritals. The third pulse of intrusive rhyolitic dykes precedes the Ari el Mahsar rhyolitic dome emplacement and the dacitic flows. (iii) identification of three intra-permian tectonic events. The close relationship between volcanism and fracturation is obvious: dykes and effusive centers are located in relation with N40-N70 faults, mostly strike-slip. We present new insights on the petrology and geochronology of the Tsesdai Permian volcanism affecting the northwestern Gondwanaland margin. The studied volcanic has typical orogenic calc-alkaline signatures. For the last volcanic pulse we determined U-Pb ages of zircon by Sensitive High-Resolution Ion Microprobe (SHRIMP). The shark fin rhyolitic extrusive dome of Ari el Mahsar (sample ARM15/GPS: 33°39'51.48"N, 6° 4'2.06"W) yielded two predominant ages (603 ± 25 Ma and 286.4 ± 4.7 Ma): the young age is more concordant, being interpreted as the crystallization age of rhyolites, whilePeer reviewe

The Post-Collisional Hercynian Volcanism of Rehamna, Western Meseta, Morocco. Mineral Chemistry, Petrology and U-Pb dating

Trabajo presentado en el 2nd International congress on Permian and Triassic, celebrado en Casablanca (Marruecos), del 25 al 27 de abril de 2018The Permian volcanism of the Eastern Rehamna massif (Western Meseta) displays two large outcrops: (i) Mechra Ben Abbou to the N and (ii) Benguerir to the S. The volcanism of Mechra Ben Abbou is often interbedded in Stephanian/Autunian sandstones/conglomerates (e.g., Gigout, 1952; Hoepffner, 1982; etc.), and appears as massive/fluidal andesitic lava flows and rhyolitic domes (e.g., the Bled Mekrach garnet-bearing rhyolitic dome). The thickness of these volcanics varies from a few tens of to 500 meters depending on their proximity to the effusive centers. The latter are situated either on/near the N40E lateorogenic dextral strike-slip Wadi Tarfa fault (Hoepffner, 1982) or along the half-graben bounding the Nahilat normal fault (e.g., El Kamel and Muller, 1987; Muller et al., 1990). In the southeastern Rehamna, east of the Benguerir City, there are also massive/fluidal lava flows (andesites) and isolated volcaniclastics overlying the Autunian conglomerates (similar to those of Mechra Ben Abbou). Rhyolitic domes intruding andesitic lava flows with mingling structures at their interface also occur, showing that the rhyolitic domes and the andesiticava flows were synchronous (Baudin et al., 2003). Another outcrop of andesitic lava flows overlies an hercynian outcrop (the Jbel Kharrou structure). Late-Hercynian microgranite and microdiorite dyke swarms and sill complexes are also present in Rehamna trending N-S to N30 (more rarely N90 to N130; Gigout, 1952; Hoepffner, 1982; etc.). They fill subvertical fractures (dykes) or more frequently cleavage (sills) with thicknesses varying from 1 to 10 m (reaching 20 m). They can be lenticular over a few meters or extend over several kilometers (Hoepffner, 1982). They were emplaced after the lower Permian molasses and before the Triassic: they intrude the Rehamna granite (268 ± 6 Ma; Mrini et al., 1992) and do not crosscut the Triassic cover. One of these dykes penetrates an overlapping contact affecting the first Permian detrital deposits of Formation 1. This overlapping fault is sealed by the last terms of this Formation (El Kamel and Muller, 1987, Muller et al., 1990). The microgranitic dykes display intraplate and calco-alkaline affinities and were emplaced at 285.4 ± 6.1 Ma (Baudin et al., 2003; Bensalah, 2012). We provide new insights into the mineralogy, geochemistry and geochronology of the Rehamna volcanism affecting the northwestern Gondwanaland Permian margin. The studied volcanics are typical orogenic calc-alkaline magmatism. The origin of garnet in the Bled Mekrach rhyolites (phenocrysts, xenocrysts, restites, or secondary reaction products) will be discussed on the basis of their textures, mineral relationships and chemistry data. We determined U-Pb zircon ages by Sensitive High-Resolution Ion Microprobe (SHRIMP) on the Bled Mekrach garnet-bearing rhyolitic dome. The sample BM 20 (GPS: 32°38'19.21"N, 7°45'5.23"W) yielded two predominant ages (611 ± 20 Ma and 285.3 ± 4.9 Ma): the last age is more concordant, being interpreted as the age of crystallization of rhyolites, while 611 Ma indicate inherited zircon that is sourced from the Pan-African crust under the Rehamna. The 285 Ma rhyolite age is very similar to that one obtained on the microgranitic dykes.Peer reviewe