Maghreb Research Articles

Life History Parameters and Fishing Aspects of the Alien Nimble Spray Crab Percnon gibbesi in a Native Area of the Central-East Atlantic.

Percnon gibbesi is a native crab species characteristic of intertidal and subtidal zones of the Atlantic coast of the European Macaronesian archipelagos (Azores, Madeira, and Canary Islands), and probably also in the neighbouring rocky coasts of northwest Africa. P. gibbesi is considered an invasive alien species in almost all of the Mediterranean, with expanding populations from Spain to Turkey, including Libya; However, its biology and ecology are highly unknown, despite all its range of distribution. In the intertidal zones of Gran Canaria Island, this crab, in the intertidal zones of Gran Canaria Island, shows a carapace length range between 4.1 and 22.7 mm (4.1-22.7 in males and 5.7-22.3 in females), where females showed higher weights and lengths than males on average; However, males predominated in all samples, with a sex ratio of 1:0.57. The L∞ for this crab was estimated to be 27 ± 3 mm (23 ± 4 mm for females and 25 ± 4 mm for males). The growth coefficient (K) was 0.24 year-1, the total mortality (Z) was Z = 1.71 year-1, and the natural mortality (M) was 0.47 year-1. Although females grow faster than males, males are more abundant in the larger length classes. Although the presence of ovigerous females indicated that reproduction takes place twice a year, from March to April and from August to September, the number of cohorts detected by the modal progression analysis showed that reproduction takes place all year.

Fossil pollen resolves origin of the South African Proteaceae as transcontinental not transoceanic.

The prevailing view from the areocladogenesis of molecular phylogenies is that the iconic South African Cape Proteaceae (subfamily Proteoideae) arrived from Australia across the Indian Ocean during the Late Cretaceous (100-65 million years ago, Ma). Since fossil pollen indicates that the family probably arose in North-West Africa during the Early Cretaceous, an alternative view is that it migrated to the Cape from North-West-Central Africa. The plan therefore was to collate fossil pollen records throughout Africa to determine if they are consistent with an African (para-autochthonous) origin for the Cape Proteaceae, and to seek further support from other palaeo-disciplines. We used palynology (identity, date and location of records), molecular phylogeny and chronogram preparation, biogeography of plate tectonics, and palaeo-atmospheric and ocean circulation models. Our collation of the rich assemblage of Proteaceae palynomorphs stretching back to 107 Ma (Triorites africaensis) in North-West Africa showed its progressive overland migration to the Cape by 75-65 Ma. No key palynomorphs recorded in Australia-Antarctica have morphological affinities with African fossils but specific clade assignment of the pre-Miocene records is not currently possible. The Cape Proteaceae encompass three molecular-based clades (tribes) whose most recent apparent ancestors are sisters to those in Australia. However, our chronogram shows that the major Adenanthos/Leucadendron-related clade, originating 54-34 Ma, would have 'arrived' too late as species with Proteaceae affinities were already present ~20 million years earlier. The Franklandia/Protea-related clade arose 118-81 Ma so its distinctive pollen should have been the foundation for the scores of palynomorphs recorded at 100-80 Ma, but it was not. Also, the prevailing winds and ocean currents trended away from South Africa rather than towards, as the 'out-of-Australia' hypothesis requires. Based on the evidence assembled here, we list three points favouring an Australian origin and nine against; four points favouring an Antarctic origin and seven against; and nine points favouring a North-West-Central African origin and three against. We conclude that a gradual migration of the Proteaceae from North-West-Central Africa southeast→south→southwest to the Cape and its surroundings occurred via adaptation and speciation during the period 95-70 Ma. We caution that incorrect conclusions may be drawn from literal interpretations of molecular phylogenies that neglect the fossil record and do not recognize the possible confounding effects of selection under matched environments leading to parallel evolution and extinction of bona fide sister clades.

Siderophile element and Hf-W isotope characteristics of the metal-rich chondrite NWA 12273 – Implication for its origin and chondrite metal formation

Metal phases in primitive chondrites contain important information for understanding early Solar System processes. Northwest Africa (NWA) 12273 is an ungrouped chondrite and, due to its preternatural high modal abundance of metal grains (>60%), provides a unique perspective on the formation and evolution of primitive planetesimals. To investigate the formation of metal phases in early solar system materials we report detailed petrography, siderophile geochemistry and Hf-W isotope geochronology for NWA 12273. The primitive textures and heterogeneous mineral chemistry of chondrules, as well as siderophile element compositions of Ni-rich metal, all indicate an affinity of NWA 12273 to unequilibrated (type 3.8) ordinary chondrites that experienced limited thermal metamorphism. Modeling shows that crucial inter-element fractionations among refractory siderophile elements for kamacite in NWA 12273, were most likely caused by solid metal-liquid metal partitioning, for example during partial melting of Fe-Ni metal containing ∼3.9 wt.% of S. Analysis of the metal fractions within NWA 12273 gives a Hf-W model age of ∼2.4 Ma after CAI formation (ε182W6/4=−3.29±0.11), older than metal formation in most of H chondrites and IIE irons. In comparison with published data for chondrites and ‘non-magmatic’ iron meteorites, siderophile element data suggest that the metal phases in NWA 12273 may have originated from similar precursor materials and/or accreted in adjacent nebular locations to IIE irons and H chondrites. These primary planetesimals experienced impact-related evaporation and mixing followed by rebuilding of the secondary body. This scenario is consistent with that proposed for IIE and other silicate-bearing iron meteorites, indicating that the building blocks of some chondrite parent bodies were not entirely primitive (undifferentiated) materials.

The genera Egmundella Stechow, 1921 and Cyclocanna Bigelow, 1918 (Cnidaria, Hydrozoa) in waters of Northwest Africa.

In this paper, we study material belonging to the hydroid genera Egmundella Stechow, 1921 and Cyclocanna Bigelow, 1918 collected off the coast of Northwest Africa, from Morocco to Guinea Bissau, between 2004 and 2012, during several international surveys. Currently, the genus Egmundella is included in the family Campanulinidae Hincks, 1869, but its taxonomic status is doubtful, since most of the life cycles of its species are unknown. A total of four species have been identified: E. grimaldii Leloup, 1940, E. modesta Millard & Bouillon, 1975, E. superba Stechow, 1921 and E. ansini n. sp. Egmundella grimaldii is found for the first time since its original description, and fertile material is described herein. Its gonotheca is morphologically similar to that of C. producta (G.O. Sars, 1874), suggesting that both species could be congeneric. A description of specimens of C. producta collected along the NW African coast is also provided.

Geology and stratigraphy of the Neogene section along the Oued Beth between Dar bel Hamri and El Kansera (Rharb Basin, northwestern Morocco) and its otolith-based fish fauna: a faunal inventory for the Early Pliocene remigration into the Mediterranean

The coquina on the banks of the Oued Beth in the Rharb Basin in northwestern Morocco has long been known to be exceptionally rich in fossils. The stratigraphic position ranging from the Late Miocene to the Pliocene has been controversial, however. In the course of my master’s degree field work in 1975/76, I mapped the right bank of the Oued Beth from Dar bel Hamri to El Kansera. Following multiple recent studies in the general region, I here review my results and present an updated comprehensive stratigraphic and geologic frame for the first time. The coquina near Dar bel Hamri is interpreted to be of Early Pliocene age, possibly containing some reworking of Late Miocene fossils. The coquina and other locations along the Oued Beth have yielded a rich otolith assemblage, which is described in this article. It represents the first fossil otolith-based fish fauna described from Northwest Africa and contains 96 species, 16 of which are new. The new species in the order of their description are Diaphus maghrebensis n. sp., Ophidion tuseti n. sp., Centroberyx vonderhochti n. sp., Myripristis ouarredi n. sp., Deltentosteus planus n. sp., Caranx rharbensis n. sp., Trachurus insectus n. sp., Parapristipoma bethensis n. sp., Pomadasys zemmourensis n. sp., Cepola lombartei n. sp., Trachinus maroccanus n. sp., Trachinus wernlii n. sp., Uranoscopus hoedemakersi n. sp., Uranoscopus vanhinsberghi n. sp., Spondyliosoma tingitana n. sp., and Opsodentex mordax n. sp. In addition, a new species is described from the Tortonian and Zanclean of Italy: Rhynchoconger carnevalei n. sp. Some additional otoliths are described from another Northwest Moroccan location of Early Pliocene age near Asilah, 50 km south of the Strait of Gibraltar. The Early Pliocene fish fauna from Dar bel Hamri in the Rharb Basin is also of interest, because it constitutes the nearest Atlantic fauna of the time of the reconnection of the Mediterranean with the Atlantic and may have acted as a hosting area for the remigration of fishes into the Mediterranean. Indeed, the correlation is high between the Northwest Moroccan and the well-known time-equivalent Mediterranean fish fauna, but the Moroccan fauna also contains a good proportion of putative endemic taxa and taxa with tropical West African affinities that apparently did not migrate into the Mediterranean. Thus, the Early Pliocene fish fauna from the Rharb Basin represents a unique assemblage for which I propose the biogeographic term “Maghrebian bioprovince.”

Upper limits of water contents in olivine and orthopyroxene of equilibrated chondrites and several achondrites

AbstractHydroxyl defects in nominally anhydrous minerals (NAMs) were potential carriers of water in the early Solar System and might have contributed to the accretion of terrestrial water. To better understand this, we have conducted a nanoscale secondary ion mass spectrometry survey of water contents in olivine and orthopyroxene from a set of equilibrated ordinary chondrites of the L and LL groups (Baszkówka, Bensour, Kheneg Ljouâd, and Tuxtuac) and several ultramafic achondrites (Zakłodzie, Dhofar 125, Northwest Africa [NWA] 4969, NWA 6693, and NWA 7317). For calibration, we used terrestrial olivine and orthopyroxene with H2O contents determined by Fourier transform infrared. Our 99.7% (~3SD) detection limits are 3.6–5.4 ppmw H2O for olivine and 7.7–10.9 ppmw H2O for orthopyroxene. None of the meteoritic samples studied consistently shows water contents above the detection limits. A few exceptions slightly above the detection limits are suspected of terrestrial contamination by ferric oxyhydroxides. If the meteorite samples investigated accreted in the presence of small amounts of water ice, the upper limits of water contents provided by our survey suggest that the retention of hydrogen during thermal metamorphism and differentiation was ineffective. We suggest that loss occurred through combinations of low internal pressures, high permeability along grain boundaries, and speciation of hydrogen into reduced compounds such as H2 and methane, which are less soluble in NAMs than in water.

Biological features of nine deep-water fishes from the midslope of the Northwest African coast

The size distribution, sex ratio, spawning activity, and maturity of Alepocephalus bairdii, Alepocephalus productus, Alepocephalus rostratus, Bathygadus favosus, Bathygadus melanobranchus, Nezumia aequalis, Mora moro, Trachyscorpia echinata and Hoplostethus mediterraneus inhabiting the middle slope off Northwest Africa were analysed. Maturation takes place during the winter months, when a high proportion (>62%) of large individuals were observed in the mature, spawning or postspawning stage, with the exception of H. mediterraneus (57.3%). Negative allometric growth was recorded as a general pattern in both sexes, but isometric growth was recorded in females of A. productus, A. rostratus, and B. melanobranchus. Positive allometric growth was only observed in females of T. echinata. The length frequency distribution showed significant differences between sexes, except in A. productus and A. bairdii. Females of Macrouridae species were found to be larger and heavier than males. Sex ratios were generally unbalanced, but no bias was observed in N. aequalis, T. echinata, and H. mediterraneus. Relative size at sexual maturity ranged mainly between 0.66 and 0.72, but B. favosus, H. mediterraneus, and N. aequalis showed lower values (0.54–0.61). Sexual maturity is reached mainly at a size between 1 and 5 cm smaller in males than in females, except in A. bairdii and T. echinata.

Hand Magnets and the Destruction of Ancient Meteorite Magnetism

AbstractMeteorites provide invaluable records of planetary formation and evolution. Studies of their paleomagnetism have constrained accretion in the protoplanetary disk, the thermal evolution and differentiation of planetesimals, and the history of planetary dynamos. Yet, the potential of these magnetic records in advancing the field of planetary science is severely hindered by a widely used technique: application of hand magnets to assist in meteorite classification. Touching a meteorite with a magnet results in near‐instantaneous destruction of its magnetic record. Here, we showcase the destructive effects of exposing meteorites to magnets through numerical modeling, a controlled remagnetization experiment on a terrestrial basalt, and a paleomagnetic study of the oldest known Martian meteorite, the Northwest Africa (NWA) 7034 pairing group. NWA 7034 is a polymict regolith breccia containing zircon crystals with crystallization ages older than 4.4 billion years. As such it contains materials that are sufficiently old to have formed during the time Mars is most likely to have had a core dynamo. Unfortunately, we found that all nine paired stones of NWA 7034 that we investigated were remagnetized by hand magnets, as has been observed for many other hot desert meteorites. We recommend that magnets not be applied to meteorites during collection and curation. Instead, a low‐field susceptibility meter is a far more sensitive and completely nondestructive tool for meteorite classification.

Thermal effects of the excitation laser power on carbonaceous meteorite Northwest Africa 6603 by Raman spectroscopy: an undergraduate research project

Raman spectroscopy has been used extensively on meteoritic samples since it is a nondestructive tool that provides information about their structure and mineralogical composition, which can give important clues about planet formation. However, the power of the excitation laser used in this technique can alter the properties of the samples due to thermal effects. In this undergraduate research work, the laser-induced thermal effects produced on the carbonaceous chondritic meteorite Northwest Africa 6603 were studied in detail by analyzing the low- and high-resolution Raman spectra parameters of the minerals found in the inclusions and matrix of this sample as a function of the excitation power. Olivine (forsterite), graphitic carbon, pyroxene (enstatite), hematite and gehlenite were the minerals identified in the studied regions. The Raman parameters of these minerals were affected by the laser power to a greater or lesser extent, indicating an increase in structural disorder. In general, the alterations observed were permanent (reverse changes were not observed). These thermal effects were correlated with the topography of the irradiated regions by analyzing their changes using optical microscopy. The micrographs of a few regions showed changes on their topography after irradiating the regions with the maximum applied power (e.g., more depressed areas). These findings exhibited strong evidence of the thermal effects induced by the laser power on the materials found in this fragment, which must be considered to avoid alterations of the physical and chemical properties of the meteoritic samples. In addition, this work presents the first study done on the mineralogical composition of Northwest Africa 6603 using Raman spectroscopy. Furthermore, from an educational standpoint, this project exposed the involved undergraduate physics students to numerous research steps (e.g., experiment preparation, data acquisition/analysis, and manuscript preparation) which provided them with a broad spectrum of valuable scientific and technical tools for their future careers.

The Missing Link in the Genesis of the Lower Paleozoic Copper Deposits of the Anti-Atlas (Morocco): The Late Triassic Central Atlantic Magmatic Province Event

Copper mineralization in the Lower Paleozoic sedimentary cover of the Anti-Atlas (Morocco) is continually being revised not only to improve its mining capacity, but also to determine its origin, which remains a matter of debate. As evidenced by the various models proposed, the related research is fragmented, localized, and confusing. The origin of the Anti-Atlas Lower Paleozoic copper mineralization is shared between synergistic and epigenetic processes or a superposition of the two processes. Based on new tectono-magmatic data and a reinterpretation of the ore structural arrangement, we propose a link between the last concentration of copper deposits and the Late Triassic–Early Liassic CAMP (Central Atlantic Magmatic Province) tectono-thermal event, as evidenced by the significant concentration of copper mineralization in the three NE–SW corridors affected by extensional faults, some of which are filled with dolerite CAMP magma. The heat flow generated by the mafic dykes within these reactivated corridors causes mineralized fluids to up well into the sedimentary layers, depositing material rich in juvenile or leached copper, or even a mixture of the two. In some cases, these fluids are trapped by fracture systems that accompany passive folds initiated on normal faults. In other cases, these fluids can infiltrate bedding planes, and even karst caves, formed during carbonate exhumation. Notably, extensive NE–SW faults systematically cover the early Hercynian structures, suggesting that they belong to a post-Hercynian extensional episode. During the Late Triassic, the global fragmentation of the Pangaea supercontinent was manifested by the stretching of the continental crust at the margin of northwest Africa, with the simultaneous opening of the Central Atlantic Ocean and emplacement of CAMP magmatism. This last and often overlooked tectonothermal event must be considered in the remobilization and reconcentration of copper mineralization and other mineralization in Morocco.

Lead-lead (Pb-Pb) dating of eucrites and mesosiderites: Implications for the formation and evolution of Vesta

Asteroid 4 Vesta is the largest known differentiated body in the asteroid belt, and is thought to be the likely parent body of howardite, eucrite, and diogenite (HED) meteorites. Howardites likely represent the vestan surface, eucrites likely crystallized as lavas in the upper crust, and diogenites likely originated from a plutonic layer deep in the crust. HEDs are potentially linked to another group of meteorites: the stony-iron mesosiderite group, due to mineralogical, geochemical, and isotopic similarities. Collision and disruption processes in the asteroid belt are key to understanding the evolution of asteroids, with impact events generating significant volumes of melt, which, if dated, can provide information on the timing and nature of such events. We performed in situ lead-lead (Pb-Pb) dating using Secondary Ionization Mass Spectrometry (SIMS) on melt clasts (mainly comprised of pyroxene, plagioclase, ± iron-nickel metal and/or glass) in two eucrites (Serra Pelada and Northwest Africa (NWA) 2696) and phosphates targeted within three mesosiderites (Vaca Muerta, Hainholz, and Estherville), respectively. The eucrite melt clasts yielded ages of 4520 ± 11 Ma and 4528.6 ± 6.3 Ma, in Serra Pelada and NWA 2696, respectively, and are likely indicative of a major heating event, such as an impact, metamorphism due to burial, or prolonged magmatism on the parent body. Our results from targeted mesosiderite phosphate analysis yielded a younger age range of ∼3968 – 4112 Ma, similar to ages reported previously for phosphate analysis in eucrites, as well as the broad range observed previously for many HEDs, and towards the upper end of the age range observed in lunar materials. These data may suggest a period of increased impact flux or possibly several higher-magnitude impacts on the mesosiderite parent body within that timeframe. Our results add further support to the likelihood of the existence of (at least) two different parent bodies for the HEDs (Vesta) and mesosiderites (Mesosiderite Parent Body – MPB).

Disentangling orbital, sub-orbital, and tectonic signatures from lacustrine sediments developed upon a half-graben (Lake Ifrah Basin, Northwest Africa): Insights into lowest-rank T-R sequences in low accommodation basins

Lacustrine settings constitute a unique environment that preserves detailed expressions of allocyclic signals such as those of climate and tectonics. Possible decryption of these signatures stems from careful scrutiny of the sedimentation dynamics (temporary base-level variations), lake-level fluctuations (accommodation), and resulting strata bounding surfaces that are used to build a conventional sequence stratigraphic framework. However, due to discrepancies between marine, to which this approach has been initially dedicated, and lacustrine settings (especially regarding the physical scale), deciphering climate from tectonic forcing becomes unwieldy in such interior basins. The present work deals with this challenge and provides insights from a case study where lacustrine sedimentation occurs on a tectonically active half-graben within a key climate region (Lake Ifrah, Northwest Africa). We conducted conventional sedimentological and high-resolution sequence-stratigraphic analyses, integrated with palaeolimnological proxies (geochemical elements and ostracod species). Up to five facies models (accounting for lithological domination, wind-driven energy, and lake-level state) and three lowest rank T-R sequences, deposited since the Marine Isotope Stage-3 (MIS-3), have been identified. Periods with sustained high lake levels appear to be mainly precession-paced (as during MIS-3 and the Early Holocene), although the role of obliquity is shown to influence the hydrological budget as well. Furthermore, sedimentation dynamics are shown to respond to millennial timescale climate variability associated with North Atlantic cooling events (Dansgaard-Oeschger stadials, Heinrich Events) and, interestingly, to enhanced Saharan winds during the deglacial period. On the other hand, tectonism had a rather instantaneous effect on lake level and sedimentation. Two tectonic pulses marking instantaneous differential hanging-wall subsidence have triggered a sharp drop in relative lake level, hence conditioning a forced regression.We highlight the importance of the conventional high-resolution sequence stratigraphy in shaping our understanding of the cyclic interplay between orbital/sub-orbital and tectonic forcings, so as the resulting sedimentation dynamics and lake-level cycles in lacustrine settings. We stress the role of the forced regression concept and associated systems tract and bounding surfaces, as well as the importance of using ostracods and geochemical proxies to trace transgressions and cryptic surfaces with sequence-stratigraphic significance, such as the maximum flooding surface, in lacustrine settings.

Anchovy (the Engraulidae family) and All of the Potential Aspect: A literature Review

Anchovies are little pelagic fish that are widely distributed in the ocean. This fish has great potential, therefore it must be nurtured. The classic review is the research approach utilized in the literature review. The Mediterranean Sea, Northwest Africa, Bone Bay, Jepara, Ambon Bay, Morocco's Atlantic Coast, Kayeli Bay, Sri Lanka, India, Malaysia, the Red Sea of Eritrea, and Argentina are inhabited to 172 species of anchovy. The catch size, length, and weight of the fish also vary considerably. Seasonal and environmental variables play a significant effect. In certain areas, the potentials for collecting anchovies can still be expanded while maintaining sustainability. This fish is consumed by the general populace. Comprehensive nutrient profile so that it may be turned into food products (food diversification). Moreover, anchovies include vitamins A, B12, D, and E. Dried anchovies, pepes, tinned anchovies, peanut brittle, fried flour anchovies, cassava/kaoami, biscuits, snacks, chili sauce, infant food additions, and anchovies crispy-sweet are among the several forms of anchovies. By empowering the community, anchovy diversification is accomplished very successfully since it may boost their economic. Anchovy waste may also be converted into fish meal for use as quail feed

Effect of permanent stress on the time-dependent earthquake probability: implication for seismic hazard assessment in the African continent

SUMMARY Earthquake hazard assessment is the first step towards implementing prevention, preparedness and response or faster recovery actions to reduce the risk of seismic disasters. In this paper, we present a comprehensive study on present-day seismicity in terms of the estimated waiting time and conditional probability in Africa by 2022–2072 using four competing distribution models (Brownian passage time (BPT), gamma, lognormal and Weibull). We also investigate how much Coulomb stress change $\ ( {\Delta {\rm CFF}} )$ induced by previous earthquakes that occurred in neighbouring active sources should revise the probability of occurrence at the location of the next events. We analyse large earthquakes with moment magnitude, ${M}_{\rm w} \ge 6.0$, collating data from the Global Centroid Moment Tensor and from several published literature that list fault plane solutions of large African earthquakes since 1900. We assume that the data set is stationary and consists of independent events. First, the model's parameters are estimated and the results of the statistical analysis of the interevent times show clear evidence of quasi-periodic recurrence behaviour for large earthquakes ${M}_{\rm w} \ge $ 6.0 in different seismotectonic regions in Africa. Next, a comparison among the distribution models is performed with the aim of selecting the most suitable one. The results in terms of the maximum likelihood criterion and its extension (Akaike Information Criterion) indicate that, in general, the BPT and Weibull models had similar fits to each other, and performed slightly better than gamma and lognormal models. Then, we use Gaussian random distributions to treat parameter uncertainties (e.g. aperiodicity, maximum expected magnitude, slip rate and mean recurrence time) of the distribution models associated with each seismotectonic region. From repeated Monte Carlo draws, we assess uncertainties of the 50-yr conditional probability values for the next earthquake obtained from two distribution models (BPT and BPT + $\Delta {\rm CFF}$) related to the 50th percentile. The results of the BPT distribution indicate very high chances of future earthquakes in the study region where the conditional probability of a large earthquake reaches 99.5, 95.6, 83.1 and 82.2 per cent for the western branch of the East African Rift System (EARS), northwest Africa, the Afar region, and the eastern branch of EARS, respectively. Taking into account the effect of stress change from interacting sources (BPT + $\Delta {\rm CFF}$), these probabilities are slightly modified to 99.8, 98.4, 89.9 and 87.3 per cent for the western branch of EARS, northwest Africa, the Afar region and the eastern branch of EARS, respectively. These marginal increases suggest that the estimated effect of the earthquake interaction introduced by the coseismic slip of previous earthquakes on neighbouring active sources is minor if compared with the uncertainties affecting the renewal models used for the basic time-dependent conditional probability assessment.

The global spatial-temporal distribution and EOF analysis of AOD based on MODIS data during 2003–2021

The long-term global distribution study of Aerosol Optical Depth (AOD) has great significance for air pollution control, forest fire prevention and climate studies. The global spatial-temporal distribution and variation of the AOD at 550 nm are analyzed using AOD550 product of Modis/Aqua during 2003–2021. The AOD550 is also studied by Empirical Orthogonal Function (EOF) analysis method. The results show that the distribution of AOD550 has obvious regional and seasonal characteristics, and the interannual variation is distinct. The AOD550 distribution with latitude/longitude is closely related to the distribution of population and aerosol natural source. The high-AOD550 areas are mainly distributed in eastern Asia, southeast Asia, south Asia, the Middle East, northwestern Africa, central and western Africa, western waters of Africa and the Amazon region of South America; The AOD550 seasonal distribution results are JJA > MAM > DJF > SON over globe, SON > DJF > (MAM ≈ JJA) over the southern hemisphere, and MAM > JJA > DJF > SON over the northern hemisphere, respectively. Moreover, the seasonal distribution characteristics varies in different regions especially over ocean and land. The results of interannual variation show an upward trend during 2005–2011, and fluctuates during 2012–2020. The annual mean AOD550 over the northern hemisphere (0.187–0.207) is significantly higher than that of southern hemisphere (0.110–0.135), while the latter shows an increasing trend (0.0009/year). The EOF analysis results demonstrate the complexity of the AOD550 global distribution. The annual mean results show the change trends of aerosols in different regions and find some special aerosol events. While the monthly mean results show that aerosols over ocean are mostly dominated by land sources (dust and biomass burning sources), and the ocean transport pattern presents an annual cycle.

The long vowels in Maghreben dialects

The difficulty of Maghreb dialects is a stereotype for many non-Maghribans; and Our research aims to remove them. In fact, these dialects are Arabic but it differs from other Arabic dialects by a set of characteristics Like a lot of sculpting, using long vowels, and facilitating The hamza letter… In addition to the characteristics that distinguish each dialect from its Maghrebian sisters.
 Our research will attempt to analyze the phenomenon of long vowels in Western Algerian dialects; In fact, the choice of the region limits the examples presented in the research folds only; All dialects of the Islamic Maghreb share this characteristic. What are the types of long vowels in the Maghreb dialects? What is the reason for their abundance in these dialects?
 In order to answer these questions, it is necessary first to define the long vowels and enumerate their types, then to refer to the long vowels resulting from facilitating the The hamza letter, and then to search for the reasons for the large number of tides among Maghribans.

Taxonomy and nomenclature of Abutilonalbidum (Malvaceae, Malvoideae), a cryptic Saharo-Canarian species recently rediscovered in Tenerife.

Abutilonalbidum, a cryptic Saharo-Canarian species, was thought to have been last collected in 1945 in Tenerife by E.R. Sventenius. In 2019, it was rediscovered in the same area. The characteristic features of the Canarian plants are discussed, especially in relation to the morphologically similar-looking and probably closely-related species Abutilonindicum and A.bidentatum. It is concluded that the plants from Tenerife and north-western Africa indeed represent a distinct species. The species is illustrated and a key for the identification of this and related species is presented.

Appraising the late-stage magmatic fO2 of diabasic angrites with a novel phase equilibrium approach. Implications for new and existing models of angrite petrogenesis

One of the enduring problems in angrite petrogenesis is how to reconcile the extraordinary Fe-rich compositions of many angritic liquids – which seemingly require modestly oxidized fO2 conditions that fall outside the stability field of Fe-Ni alloys during primordial melting – with the geochemical and paleomagnetic evidence that the angrite parent body contains a small metallic Fe-Ni-S-C core. One of the major impediments to resolving these contradictions stems from a distinct lack of rigorous fO2 data for the angrite meteorite clan. To begin addressing this issue, we have developed a new approach for calculating magmatic fO2 values directly from the late-stage olivine-ulvöspinel- silicate liquid assemblages that are common in the volcanic or hypabyssal angrites. The adaptation of the olivine-spinel-aSiO2liq oxybarometer for use in angrites requires a careful assessment of aSiO2liq of angritic liquids. We apply the results of metal saturated angrite crystallization experiments and an analysis of the Ca-Tschermak’s-anorthite-aSiO2liq equilibrium to obtain estimates for the aSiO2liq values of angritic magmas. We then use the aSiO2liq estimates derived from the experiments and thermodynamic analysis in conjunction with the olivine-spinel-aSiO2liq oxybarometer to calculate the magmatic fO2 of Sahara 99555, D’Orbigny, and Northwest Africa 12004. With this approach we estimate oxygen fugacity values that range from ΔIW + 0 to ΔIW + 0.25. The relatively reducing fO2 values obtained from our analysis are inconsistent with redox conditions required by the oxidized melting hypothesis. Some caution is warranted in extrapolating these late-stage magmatic fO2 values to higher temperatures; however, we stress that fractionated silicate liquids typically become more oxidized with increasing crystallization via auto-oxidation (i.e., the accumulation of incompatible ferric iron in the liquid). Therefore, we suggest that late stage magmatic fO2 values from our calculations may represent the most oxidized conditions along the angrite liquid line of descent. If this interpretation is correct, a large-scale oxidation event on the APB need not be invoked to reconcile mildly reducing conditions (ΔIW−1.35) thought to have prevailed during core formation with the magmatic fO2 record preserved in angritic meteorites. Future redox studies of compositionally primitive angrites (e.g., Northwest Africa 12774) may shed new light on the redox relationships among primitive angrite magmas, evolved angrite magmas, and core forming alloys.

Constraints on martian depleted shergottite volcanism from the petrogenesis of olivine-phyric shergottites NWA 2046 and NWA 4925

The 1.1Ma ejection-paired depleted shergottites are sourced from a long-lived volcanic centre, likely located on the Tharsis plateau. Here we present bulk-rock geochemistry, mineral major- and trace-element concentrations, and in-situ maskelynite and pyroxene 87Sr/86Sr data for two depleted olivine-phyric shergottites, Northwest Africa (NWA) 2046 and NWA 4925, from this 1.1 Ma ejection event. The earliest formed olivine megacryst cores in NWA 2046 (Fo83) and NWA 4925 (Fo81) are among the most Mg-rich recorded in martian meteorites and are also in Mg–Fe equilibrium with their respective bulk-rock compositions. We infer the olivine megacrysts in NWA 2046 and NWA 4925 are phenocrysts and suggest that both samples represent melt compositions. CI chondrite-normalised rare earth element patterns for melts calculated to be in equilibrium with pyroxene in NWA 2046 and NWA 4925 are parallel to those of melts in equilibrium with maskelynite and merrillite, which suggests that both samples crystallised from continuously fractionating melts unaffected by crustal contamination. Oxygen fugacity estimates for NWA 2046 (QFM -2.7) and NWA 4925 (QFM -2.9), derived from the V-in-olivine oxybarometer, are comparable to other depleted olivine-phyric shergottites, including Tissint, Larkman Nunatak (LAR) 12095/12240, Dar Al Gani (DaG) 476 and Dhofar (Dho) 019.Effects of terrestrial alteration are observed in bulk-rock and mineral compositions from NWA 2046 and NWA 4925. The degree of terrestrial alteration is most pronounced in NWA 4925, consistent with an older reported exposure age relative to NWA 2046. The low Ni-contents of bulk-rock and olivine megacrysts in NWA 2046 and NWA 4925 suggests that both samples are not primary mantle-derived melt, but rather have undergone 8–10% and 10–13% fractional crystallisation, respectively, in a staging chamber at depth. Pyroxenes Ti/Al for NWA 2046 and NWA 4925, suggest initial crystallisation at ∼ 10 kbar, consistent with other ejection-paired olivine-phyric shergottites, indicating either a common or multiple staging chambers near the base of the martian crust. The 87Sr/86Sr compositions for unaltered maskelynite grains in NWA 2046 (0.70130 ± 7) and NWA 4925 (0.70128 ± 10) suggest that both samples originate from a similar mantle source to other depleted olivine-phyric shergottites, particularly DaG 476, and Sayh al Uhaymir (SaU) 005 and Yamato 980459 (Y-980459).

Non-destructive Elemental Analysis of Lunar Materials with Negative Muon Beam at J-PARC

In the last decade, non-destructive elemental analysis using negative muon beams advanced significantly. This method can be used to determine the elemental composition of bulk materials without causing damage. In this study, we performed a negative muon irradiation experiment for a Northwest Africa 482 lunar meteorite (NWA482), which was installed in a stainless steel analysis chamber. The analysis chamber was filled with helium gas to suppress the background signals caused by air-scattering muons. The muonic X-rays from Al, Fe, Ca, Mg, Si, and O in the samples were detected using six high-purity germanium semiconductor detectors arranged around the analysis chamber. To correct the X-ray self-absorption effect of the samples, a Monte-Carlo simulation using Geant4 toolkit was used. Based on the quantitative analysis for muonic X-ray measurement with the correction application from the simulation, we successfully investigated the analytical sensitivity of each element in meteorites based on the NWA482 data.