New age estimates for the Palaeolithic assemblages and Pleistocene succession of Casablanca, Morocco

Marine and aeolian Quaternary sediments from Casablanca, Morocco were dated using the optically stimulated luminescence (OSL) signal of quartz grains. These sediments form part of an extensive succession spanning the Pleistocene, and contain a rich faunal and archaeological record, including an Acheulian lithic assemblage from before the Brunhes–Matayama boundary, and a Homo erectus jaw from younger cave deposits. Sediment samples from the sites of Reddad Ben Ali, Oulad J’mel, Sidi Abderhamane and Thomas Quarries have been dated, in order to assess the upper limits of OSL. The revision of previously measured mammalian tooth enamel electron spin resonance (ESR) dates from the Grotte des Rhinocéros, Oulad Hamida Quarry 1, incorporating updated environmental dose rate measurements and attenuation calculations, also provide chronological constraint for the archaeological material preserved at Thomas Quarries. Several OSL age estimates extend back to around 500,000 years, with a single sample providing an OSL age close to 1 Ma in magnetically reversed sediments. These luminescence dates are some of the oldest determined, and their reliability is assessed using both internal criteria based on stratigraphic consistency, and external lithostratigraphic, morphostratigraphic and independent chronological constraints. For most samples, good internal agreement is observed using single aliquot regenerative-dose OSL measurements, while multiple aliquot additive-dose measurements generally have poorer resolution and consistency. Novel slow-component and component-resolved OSL approaches applied to four samples provide significantly enhanced dating precision, and an examination of the degree of signal zeroing at deposition. A comparison of the OSL age estimates with the updated ESR dates and one U-series date demonstrate that this method has great potential for providing reliable age estimates for sediments of this antiquity. We consider the cause of some slight age inversion observed at Thomas Quarries, and provide recommendations for further luminescence dating within this succession

La grotte des Rhinocéros à Casablanca (Maroc) : conclusions préliminaires sur un site du second Acheuléen régional et perspectives de recherche

International audienc

La grotte des Rhinocéros à Casablanca (Maroc) : conclusions préliminaires sur un site du second Acheuléen régional et perspectives de recherche

International audienc

Green synthesis of silver nanoparticles using Phoenix dactylifera seed extract and their electrochemical activity in Ornidazole reduction

Over the past few decades, nanotechnology evolved into a significant, interdisciplinary research field on a global scale. Due to their extraordinary physicochemical, optical, and biological qualities, noble metal nanoparticles like gold, silver, palladium, and platinum are widely used in a variety of industrial and pharmaceutical procedures. In this study, a quick, low-cost, and environmentally friendly approach was used to create GAgNPs. Without using hazardous chemical substances, GAgNPs were produced using Phoenix dactylifera seeds extract as a reducing and stabilizing agent. The synthesized GAgNPs were characterized by UV-Visble, X-ray diffraction, and scanning electron microscopy. The presence of GAgNPs confirmed by the appearance of peak at 420 nm employing UV-Vis method, also affirmed by X-ray diffraction pattern, and the calculated size was about 28.72 nm. The electrochemical activity of GAgNPs was investigated through the elaboration of carbon paste-based sensor for the determination of ornidazole. The GAgNPs modified carbon paste electrode displayed a linear concentration range from 1.0 × 10−3 mol L−1 to 5.0 × 10−5 mol L−1 with a detection limit and quantification limit of 3.8 × 10−6 mol L−1 and 1.2 × 10−5 mol L−1, respectively. The proposed sensor was used for ornidazole analysis in milk samples, providing satisfactory recoveries of 105.7% and 102.7% with RSD below 4%