Study of Monogenic Volcanism in a Karstic System: Case of the Maar of Lechmine n’Aït el Haj (Middle Atlas, Morocco)

The Lechmine n’Aït el Haj maar (LNH) is a mixed phreatomagmatic-strombolian vent located in the Causse of the Middle Atlas. The application of tephrostratigraphic, and geophysical studies to the volcaniclastic deposits allowed interpreting the volcanic dynamics of this volcano set up during the Quaternary. Pyroclastic deposits allow us to understand the chronology of the eruptions. These are organized in four eruptive phases. The basal sequences are phreatomagmatic, followed by a strombolian unit. The last activity of LNH is phreatomagmatic. The structural analysis revealed a localized distension signed by fracture geometry, the mixed nature of the volcanism, tectonic markers, and the mechanisms of syn-eruptive tectonics. This subsidence, controlled by the NW-SE to WNW-ESE directions tends towards a strike-slip regime fault NE–SW during the phreatomagmatic-strombolian transition. The latter is favored by the position of the LNH volcano on the path of faults of cryptokarstic origin. The LNH maar is one of numerous well preserved monogenic volcanoes of the Causse of the Middle Atlas. The appropriation of this geoheritage is very important for tourism and territorial development of the region

Antimicrobial and antiradical properties of Hammada scoparia (Pomel) Iljin

Background: Hammada scoparia (Pomel) Iljin (HS), is commonly used by traditional healers in Morocco against microbial and fungal infections. We studied antimicrobial, antifungal and antiradical effects of organic extracts in vitro in order to confirm traditional utilization after phytochemical screening.Materials and methods: Aerial parts of HS have been extracted by hydro-distillation using Clevenger-type apparatus, and the chemical composition was realized by Gas Chromatography coupled with Mass Spectroscopy (GC/MS). The antioxidant activity has been evaluated using DPPH test, while the antimicrobial tests of HS extract were conducted on twenty-eight bacterial strains and antifungal on twelve fungal strains.Results: Chemical characterization of HS essential oils (EO) confirmed the presence of carvacrol (82,28%), p-cymene (2,52%), γ- terpinene (2,18%) and Z-caryophyllene (2,04%). Antimicrobial tests of HS extract showed a moderate antibacterial activity without antifungal effect. In addition, HS exhibited a very powerful antiradical activity with IC50 = 1,2 mg/ml compared to that of ascorbic acid (IC50 = 0,5 mg/mL) and butylated  hydroxyanisole (0,8 mg/mL).Conclusion: To our knowledge, this is the first demonstration that HS directly inhibits the growth of microorganisms in vitro, and further validates its traditional use as an antiseptic by traditional Moroccan healers. Keywords: polyphenolics, Hammada scoparia, antimicrobial, antifungal, antioxidant

Ba- and Ti-rich oxymica from nephelinites in the Middle Atlas Volcanic Province, northern Morocco

International audienceA Ba- and Ti-rich mica (up to 14.0 wt% BaO and 13.1 wt% TiO2) occurs in nephelinites from the Middle Atlas Volcanic Province, Morocco. The rocks show a porphyritic texture composed of olivine, Ti-rich augite, nepheline and Ti-rich magnetite. Oxyphlogopite is found in secondary assemblages consisting of zeolites, clinopyroxene and Ti-oxides. This mineral occurs mostly as euhedral to subhedral crystals lining the walls of zeolitic veinlets and cavities in the nephelinites. The coupled substitutions of (1) Ba for K in the interlayer site and Si for Al in the tetrahedral site and (2) Ti4+ for Mg in the octahedral site and O2- in the (OH, F) site are major mechanisms of Ba and Ti incorporation in these micas. The average structural formula, calculated on the basis of 12 (O, OH, F, Cl), is (Si2.515-Al1.482-Fe3+0.003)4.000 (Al0.050-Ti0.661-Fe2+0.798-Mn0.012-Mg1.500)3.021 (Ca0.014-Ba0.398-Na0.066-K0.502)0.980 O10 (F0.308-Cl0.009-O1.319-OH0.365)2.001, suggesting a combination of oxyphlogopite and oxykinoshitalite, with contribution from the hypothetical end-member "Ti-eastonite". Ba- and Ti-rich oxymica in the nephelinites may have crystallized under the influence of Ba-rich fluids derived from nephelinitic melts during late magmatic stages. The Ba enrichment in the host nephelinites indicates a lithospheric mantle source enriched by the circulation of metasomatic fluids

ANTIMICROBIAL AND ANTIRADICAL PROPERTIES OF HAMMADA SCOPARIA (POMEL) ILJIN

Background: Hammada scoparia (Pomel) Iljin (HS), is commonly used by traditional healers in Morocco against microbial and fungal infections. We studied antimicrobial, antifungal and antiradical effects of organic extracts in vitro in order to confirm traditional utilization after phytochemical screening. Materials and methods: Aerial parts of HS have been extracted by hydro-distillation using Clevenger-type apparatus, and the chemical composition was realized by Gas Chromatography coupled with Mass Spectroscopy (GC/MS). The antioxidant activity has been evaluated using DPPH test, while the antimicrobial tests of HS extract were conducted on twenty-eight bacterial strains and antifungal on twelve fungal strains. Results: Chemical characterization of HS essential oils (EO) confirmed the presence of carvacrol (82,28%), p-cymene (2,52%), γ-terpinene (2,18%) and Z-caryophyllene (2,04%). Antimicrobial tests of HS extract showed a moderate antibacterial activity without antifungal effect. In addition, HS exhibited a very powerful antiradical activity with IC50 = 1,2 mg/ml compared to that of ascorbic acid (IC50 = 0,5 mg/mL) and butylated hydroxyanisole (0,8 mg/mL). Conclusion: To our knowledge, this is the first demonstration that HS directly inhibits the growth of microorganisms in vitro, and further validates its traditional use as an antiseptic by traditional Moroccan healers