The Numidian sand event in the Western Rif Chain (Northern Morocco)

We report on new sedimentological and biostratigraphical data concerning the “Numidian sandstones” outcropping in the Western Rif Belt. The analyzed sections are located south of Tangier city, close to the 9th April dam and pertain to the Intrarif Sub-domain, which, in turn, is part of the External Rif domain. In the western peri-Mediterranean chains, the “Numidian sandstones” display constant lithological features. We analysed six well-exposed lithostratigraphic sections, which are organized in three portions: (1) the “sub-Numidian”, mainly dominated by varicolored clays, (2) the “Numidian sandstones”, which includes predominantly massive quartzarenitic sandstones, sometimes interbedded with mudstones, and, finally, (3) the “supra-Numidian”, characterized by alternation of light green marls and thin-bedded siltstones. Stratigraphic sections of the “Numidian sandstones” were measured and described to provide detailed sedimentological characterization and facies analysis. The “sub-Numidian”, thick more than 100 meters, is commonly made of varicoloured clays, which in all the studied sections shows a horizon rich in Tubotomaculum. In the study area, the “Numidian sandstones” are about 1100 m thick; their facies analysis have been performed by using Pickering et al. (1995) classification scheme. The basal part of the examined sections shows similar characteristics: proximal channels filled by very thickbedded disorganised pebbly sandstones and amalgamated structureless sandstones (Facies A1.4 and B1.1). The base of the beds is scoured and sometimes shows decimetresized mud clasts torn away from the substratum. Paleocurrents measurements, mainly indicated by flute casts, are from southeast to northwest. Upward, coarse-grained quartzarenitic sandstones mainly characterize the middle part of all the sections. They are organized in massive and thick-bedded pebbly-sandstones, micro-conglomerates (Facies A2.4 and A2.5), and disorganised thick sandstones strata, often marked by fluid escape structures (Facies B1.1), revealing flows processes controlled by high-density turbidity currents and debris flows. These deposits evolve to plurimeter- to decimetre-thick mediumgrained sandstone and mud couplets (Facies C2.3) with a mainly fining-and thinning-upward trend, which we consider to be attributable to lobe and fringe lobe deposition. Commonly, the uppermost part of the sections shows a restoration of disorganised pebbly sandstones facies (Facies A1.4). The “supra-Numidian” caps the thick “Numidian sandstones” and is made up by about 200 m of bioturbated marls rich in planktonic foraminifera and fine-grained silty/muddy deposits. These latter show sedimentary structures related to unidirectional flows, probably owed to deep contourites currents. References Pickering K.T., Hiscott R.N., Kenyon N.H., Ricci Lucchi F. & Smith R. (editors) 1995. Atlas of architectural styles in turbidite systems. London: Chapman & Hal

The Numidian sand event in the Burdigalian foreland basin system of the Rif, Morocco, in a source-to-sink perspective

During the Tertiary evolution of the Western Mediterranean subduction system, a migrating foreland basin system developed between the Maghrebian orogenic belt and the adjacent African Craton. However, a comprehensive reconstruction of the foreland basin systems of the Rif Chain is still missing. By integrating field observations with quantitative biostratigraphic data from calcareous nannofossil assemblages, sandstone composition, and detrital zircon U-Pb geochronology from selected stratigraphic successions, we reconstruct the foreland basin system that developed in the early Miocene in front of the growing Rif orogen. The successions analyzed are representative of (1) the classical “Numidian Facies” from the Intrarifian Tanger Unit and (2) the Numidian-like deposits (mixed successions) of the “Mérinides Facies” from the “Maghrebian Flysch Basin” and the “Beliounis Facies” from the Predorsalian Unit. Our petrographic analyses and detrital zircon U-Pb ages show that the quartzarenites of the “Numidian Facies” originated from the African Craton, whereas the sublitharenites and feldspathic litharenites from the Mérinides and Beliounis Facies originated from a cratonic area and the exhuming Rif Chain. Our biostratigraphic analyses suggest a simultaneous arrival of the quartz grains in the Numidian, Mérinides, and Beliounis deposits, which indicates that their deposition occurred at ∼1 m.y. (ca. 20–19 Ma, early Burdigalian) and allows us to delineate the early Burdigalian foreland basin system of the Rif Chain. The foreland depozone received the “Numidian Facies,” the foredeep-hosted ~2000 m of the “Mérinides Facies” and the Beni Ider Flysch, whereas the wedge-top depozone was characterized by deposition of the “Beliounis Facies.” The Numidian Sandstones and the Numidian- like deposits analyzed in Morocco show the same age as similar deposits from Algeria, Tunisia, and Sicily, which suggests a comparable early Burdigalian tectono-sedimentary evolution along the southern branch of the Western Mediterranean subductionrelated orogen

The Jurassic climate change in the northwest Gondwana (External Rif, Morocco): Evidence from geochemistry and implication for paleoclimate evolution

The present work deals with Jurassic deposits belonging to the External Rif chain. It is well known that the Jurassic time was a crucial period in the earth’s history as witness of significant climate changes. This work aims to provide a preliminary reconstruction of the regional Jurassic paleoclimate of the northwest Gondwana hinterland and its global paleogeographic context. We used diverse geochemical proxies to unravel paleoclimate of the Jurassic sediments accumulated in the Atlantic and Tethysian hyperextended passive margins bordering the northwest Gondwana. We reconstituted their paleo-humidity, paleo-precipitation, paleo-weathering, paleoproductivity, paleo-floral landscape distribution in the Gondwanaland, the paleo-redox, paleo-oxygenation and paleosalinity of the bordering oceanic sinks. The obtained results indicate that the early Jurassic climate was cool with low rainfall and productivity, while the middle Jurassic was characterized by a semi-moist warm climate with high chemical weathering and subsequent seaward terrigenous supply. The Uppermost Jurassic climate was warm, semi-moist to moist with a return to an arid cold climate marked by high rainfall amount which yielded more terrigenous material to the bordering Tethysian and Atlantic hyperextended passive margins around the northwest Gondwana hinterland. The result of this research reveals, among others, the control of the first-order geodynamic processes on the Jurassic mid-latitude climate change, such as plate tectonics reorganization, oceanic seafloor spreading, and subsequent volcanic activity. The latter may triggered a climate shift from early Jurassic dry “cool” to middle-late Jurassic wet warm “greenhouse” climate conditions around the northwest Gondwanaland. Besides, the Jurassic climate change may have been also controlled by successive megamonsoons that occurred through the Inter-Tropical Convergence Zone (ICZ) over margins and oceanic realms bordering the northwest Gondwanaland

Tubotomaculum: a bacterially-mediated polymetallic nodule

Since the 50s of the last century, several authors have investigated the nature of Tubotomaculum: enigmatic Mn-Fe mineralizations occurring in the latest Oligocene – Early Miocene varicoloured clays of the western Mediterranean area. Some authors regarded these structures as fossil traces[1], as fossil corals covered by Fe-oxides and manganite[2], or as inorganic Mn-Fe nodules with rhodocrosite, siderite, and non-crystalline Mn-oxides[3]. Due to the lack of mineralogical and geochemical data the processes of crystallization and growth are still unclear and questionable. Mn-oxides are significant environmental indicators for composition, pH, Eh, and biological activities. However, since they occur typically as cryptocrystalline and fine-grained mixtures of different Mn-phases and additional minerals, like Fe-oxides, carbonates and silicates, their characterization is a real challenge that requires a multimethodological approach. The Tubotomaculum samples analyzed in this work are from the western Rif in northern Morocco. The samples come from the pre-Numidian varicoloured clays of a section sampled close to the dam of the Reservoir Lake 9th April. This work is a first contribution aimed at providing a proper characterization of these mineralizations and to define the processes that led to their crystallization and growth. The final aim of this work is to provide evidence of the paleo-environmental conditions affecting the late Oligocene-early Miocene pre-Numidian sedimentary basin of northern Morocco. Crossing SEM-EDS, XRPD, TEM, 3D ED and FT-IR and Raman spectroscopy data, a proper characterization of the samples was achieved. Tubotomaculum consists of a very fine mixture of birnessite [(Ca,Na)(Mn4+,Mn3+)O4·1.5HO] and todorokite [(Ca,Na,K)(Mn4+,Mn3+)6O12·nHO], Mn-phases commonly recognized in oceanic nodules[4]. In particular, todorokite could be related to biological processes[5]. Goethite, hematite, kaolinite, and quartz were also found. All these minerals have a clear spatial distribution in the samples: millimetric Mn-Fe rich layers grow around central nuclei of clay minerals, quartz and/or bone fragments. In these layers 3-5 μm Mn-rich spheroidal structures occur in a Fe-rich matrix. SEM analyses reveal the presence of rounded structures suggesting microbial colonies. Their occurrence points to a biofilm formed by a single species of bacteria. These features allow to exclude the secondary diffusion of Mn and Fe from the surrounding sediment, suggesting a primary deposition of these mineralizations, possibly mediated by bacterial activity. According to these evidence, Tubotomaculum cannot be considered as a fossil trace or fragments of fossil coral. They are polymetallic nodules made up of a very fine-grained mixture Mn-Fe oxides, whose growth was biologically mediated by bacterial activity. Allegedly, such activity played a key role in catalyzing the oxidation of Mn2+ on the late Oligocene-early Miocene sea floor of northern Morocco

Genomic Instability and Pro-Tumoral Inflammation are associated with Primary Resistance to Anti-PD1 + Anti-Angiogenesis in Malignant Pleural Mesothelioma

International audienceCancer immunotherapy combinations have recently shown to improve the overall survival of advanced mesotheliomas especially for patients responding to those treatments. We aimed to characterize the biological correlates of malignant pleural mesotheliomas primary resistance to immunotherapy and anti-angiogenics by testing the combination of pembrolizumab, an anti-PD-1 antibody, and nintedanib, a pan anti-angiogenic tyrosine kinase inhibitor (TKI), in the multi-center PEMBIB trial (NCT02856425). Thirty patients with advanced malignant pleural mesothelioma were treated and explored. Unexpectedly, we found that refractory patients were actively recruiting CD3+CD8+ cytotoxic T-cells in their tumors through CXCL9 tumor release upon treatment. However, these patients displayed high levels of somatic copy number alterations in their tumors that correlated with high blood and tumor levels of IL-6 and CXCL8. Those pro-inflammatory cytokines resulted in higher tumor secretion of VEGF and tumor enrichment in regulatory T-cells. Advanced mesothelioma should further benefit from stratified combination therapies adapted to their tumor biology