The Canary Islands represent one of the most intensively studied intraplate volcanic systems in the eastern Atlantic. The origin of Canary Island magmatism remains a matter of debate. Nevertheless, isotopic studies consistently indicate that mantle sources beneath the archipelago are compositionally heterogeneous and spatially complex. This study presents a methodologically consistent compilation of more than 300 Sm–Nd isotopic analyses from all emerged islands of the Canary Archipelago, complemented by new high-precision ID-TIMS data of the most recent eruption from La Palma Island. All isotopic parameters, including εNd(0), εNd(T), and single-stage depleted mantle model ages (TDM), were recalculated using consistent decay constants and CHUR reference values to ensure comparability across the dataset. The results reveal a heterogeneous spatial distribution of isotopic variability across the archipelago. Western islands (El Hierro and La Palma) display restricted εNd ranges and predominantly juvenile TDM ages. Central islands exhibit broader isotopic dispersion, whereas eastern islands (Fuerteventura and Lanzarote) show the widest εNd interval, including negative values, and the oldest TDM ages. Importantly, inter-island variability often exceeds the intra-island dispersion. This spatial pattern indicates laterally structured mantle domains beneath the archipelago. Although the data do not exclude a deep thermal anomaly, they are inconsistent with a purely homogeneous plume model. Instead, magma generation beneath each island is strongly influenced by the compositional architecture of the underlying mantle lithosphere. These findings support previous interpretations of compositionally heterogeneous mantle sources beneath the Canary Islands and provide additional constraints on the evolution of intraplate volcanism in the eastern Atlantic.
Xenoliths hosted in alkaline basaltic lavas provide constraints on the composition and evolution of the upper mantle and lower crust, as well as on deep igneous processes beneath volcanic zones. This study investigates xenoliths occurring in pyroclasts and lavas of the Roca Negra volcano (Neogene–Quaternary Catalan Volcanic Zone). Petrographic analysis and major- and trace-element mineral chemistry were used to characterise xenolith lithologies, to estimate their pressure-temperature equilibrium conditions and constrain the nature of the upper mantle and lower crust. The xenolith assemblage includes ultramafic and mafic rocks corresponding to classical Type II (aluminous-augite) xenoliths in basaltic lavas, together with leucocratic igneous to meta-igneous rocks. Ultramafic and mafic xenoliths are cumulates dominated by clinopyroxene and/or amphibole and formed from the crystallisation and mixing of alkaline and tholeiitic melts more evolved than the host basalts. Most leucocratic xenoliths (gabbronorites, gabbros and anorthosites), with cumulate and granoblastic textures, derive from more saturated tholeiitic or high-Al basalts emplaced earlier within the lower-middle crust. Thermobarometric estimates for the ultramafic and mafic xenoliths (1140–949 °C; 1.0–0.6 GPa) indicate equilibrium conditions spanning the upper mantle and lower crust, whereas estimates for leucocratic xenoliths (1159–933 °C; 0.7–0.4 GPa) correspond to the lower to middle crust. These results indicate that the crust-mantle transition beneath the Catalan Volcanic Zone, at approximately 29 km depth, is composite, and consists of ultramafic-mafic cumulates intruded into mantle spinel peridotites and older layered igneous rocks of the lower to middle crust prior to the eruption of the host alkaline lavas.
The Tijekht and Tazoult n’Ouzina anticlines, located in the eastern Anti-Atlas of Morocco, exhibit a complex structural history, largely linked to the Variscan orogeny. This study presents a detailed analysis of the structural and tectonic evolution of these anticlines, emphasizing on both ductile and brittle deformation, and to determine the relationship between Variscan shortening and the large distribution of mineralized veins in the Tijekht and Tazoult n’Ouzina zones. Field data, satellite imagery, and structural analysis have been used to investigate the geometry and kinematics of key structures, such as anticlines and fault systems. The finding reveals a multi-phase tectonic history with three significant deformation phases, including early NW-SE compression that generated large-scale folds, followed by NE-SW compression, which reactivate pre-existing faults and generates miner folds with N-S to NNE-SSW axes, leading to an interference pattern and it is interpreted to have resulted in the refolding of the Tijekht anticline. The later phase is represented by extensional tectonics associated with the opening of the Central Atlantic. The structural analysis exhibit four fault systems: NE-SW, N-S to NNE-SSW, ENE-WSW, and E-W to ESE-WNW. Particularly the NE-SW and E-W oriented fault systems, are closely associated with significant mineralization, including barite, lead, copper, and zinc sulfides. These structures reflect a multi-phase tectonic history affecting the Tijekht and Tazoult n’Ouzina anticlines.
Zircon studies in mafic and ultramafic rocks are particularly valuable because they can reveal deep-mantle petrogenetic and geodynamic processes. These studies, however, are hindered by the scarcity and uneven distribution of zircon in the mantle and mantle-derived rocks. Consequently, finding zircon in these rocks is inherently difficult and strongly influenced by the zircon abundance, grain size, volume, and the number of samples searched. Here, we describe a method for in-situ zircon identification and extraction for further analytical studies. To this end, we cut four representative 2 × 3 cm slabs, one from the granite and three from the gabbro, and carefully polished one side to enable automated large-area elemental mapping with SEM, EPMA, and µ-XRF using WDS and or EDS. Of all these, µ-XRF offers the best balance among acquisition time, surface coverage, spatial resolution and result quality. To overcome spectral interferences affecting the Zr signal, the method uses multidimensional analysis based on suitable ratios of the X-ray lines produced by the sample's major and, eventually, minor elements. Zircon-bearing pixels are then discriminated utilising a combination of global, local, and probabilistic statistical classifiers, such that zircon identification is accepted only where consistent statistical behaviour is reproduced across independent methods. Overall, the protocol enables reproducible detection and extraction of zircon down to 50 µm in grain size while minimising both false positives and false negatives. The same methodology can be used to locate other Zr-bearing (e.g., baddeleyite, zirconolite, srilankite) and Zr-lacking (e.g., apatite, xenotime monazite, rutile, chromite) accessory minerals that may be present in the rock sample.
The Puente del Congosto intrusive complex, exposed along the northern margin of the Ávila batholith (Central Iberian Zone, Spain), documents the post-collisional association between sanukitoid (vaugnerite-type) mafic–intermediate rocks and granodiorites. Field relationships show high-Mg gabbros forming angular bodies enclosed by diorites and quartz-diorites, which interact with granodiorites through magma mingling and enclave formation. Despite sharp contacts, whole-rock geochemistry defines a near-continuous compositional spectrum from high-Mg gabbros (MgO >10 wt
210Pb short-lived radionuclide provides a valuable tool for reconstructing depositional histories and environmental changes over the last 110 years. However, the complex environmental dynamics and the numerous anthropogenic processes that characterize coastal areas have the potential to disrupt radionuclide activity profiles in geological archives and, therefore, to hinder the accuracy of geochronological models. In this study, we evaluate the radioisotopic records (210Pb, 137Cs, and 239+240Pu) of five case studies representing different environmental conditions in Cantabrian coast estuaries, through a multidisciplinary perspective that combines sedimentological (grain size), micropaleontological (benthic foraminifera), and geochemical (trace metals and Hg) data, alongside documentary records (historical aerial photography). Distinct downcore radionuclide fingerprints were identified and classified into four different profile styles: ideal, smoothed, interrupted, and erosional. The integration of multiproxy evidence allowed the validation of 210Pb-derived geochronological frameworks and, in those cases where absolute chronology could not be obtained, to establish relative age models. The study highlights the importance of a critical evaluation of radionuclide profiles within a multiproxy approach to accurately reconstruct the recent environmental transformation of coastal ecosystems.
A large sample of helical burrows based on the circular helix typical of the ichnogenus Gyrolithes is analysed. The main goals are: (1) a statistical analysis of four measurements taken from the burrows, and the calculation: based on these—of four dimensionless parameters defined for their morpho-theoretical study: relative pitch, adaxial ratio, helix slope and eccentricity; and (2) to quantitatively test the hypothesis that helical penetration into the sediment implies energy saving, since this type of helical tubes can be considered mechanically analogous to an inclined plane. A principal component analysis of the four measurements clearly separates two groups: a large group of burrows characterized by measurements exceeding 1 cm, and a small group with measurements below 1 cm. The large group differs from the small one in the values of relative pitch and adaxial ratio; however, helix slope and eccentricity are similar in both groups. The adaxial ratio, eccentricity and helix slope allow for the calculation of the helix length per whorl. Both helix slope and adaxial ratio exhibit critical values that determine whether the burrow structure remains stable or collapses; therefore, there is also a critical value for the helix length per whorl. The energy-saving hypothesis implies a low helix slope (a critical threshold) and moderately high adaxial ratio values, but in both cases close to their respective critical values. The helix length per whorl values have also to be short and slightly exceed its critical value. The Gyrolithes sample generally conforms to these criteria. An image analysis of the ichnogenus Daimonelix yields similar results for helix slope, adaxial ratio and eccentricity. The energy-saving strategy results in a burrow morphology that allows it to meet various environmental requirements of its producers. This allows for a discussion of the notion of behavioral exaptation.
In the Cabo Ortegal Complex, NW Iberia, the subduction-related Variscan (ca. 390 Ma) high-pressure granulites of the Bacariza Formation (Cambrian protolith age, ca. 500 Ma) commonly show banding/regions defined by varying mineral abundance of amphibole and plagioclase-quartz that overprint high-pressure high-temperature (HP-HT) garnet and Na-rich diopsidic clinopyroxene, implying retrogression-related replacements triggered by the infiltration of H2O-bearing fluids. Regions with varied amphibole+plagioclase and garnet+clinopyroxene abundances are similar in bulk-rock composition, however, denoting insignificant metasomatism during the post-peak infiltration of H2O-fluid. On the contrary, bands rich in carbonate (Mg-calcite) denote substantial changes in bulk-rock composition relative to the original magmatic protoliths. This study presents petrographic and geochemical data and thermodynamic modelling of metamorphosed banded metasomatic carbonate-bearing mafic granulites of the Bacariza Formation. The textural-mineral assemblage development of the rocks made of varied amounts of garnet, Na diopside, calcite, epidote, scapolite, plagioclase, amphibole, rutile, titanite and phengite, plus relict K-feldspar and chlorite, denotes pre-metamorphic CaO-K2O-CO2-SO3-H2O metasomatic transformations to varied extent and subsequent roughly isochemical granulitic HP–HT metamorphism characterized by garnet + Na diopside+calcite+epidote+titanite+SO4-CO3-rich scapolite±plagioclase in the more carbonated bands. U-Pb dating of texturally-peak titanite yielded 387.3 ± 1.4/5.8 Ma, interpreted as a cooling age near the peak of metamorphism, while dating of texturally-peak epidote yielded 373.2 ± 3.7 / 6.6 Ma of uncertain significance. Subsequently, these assemblages did not experience significant retrogression during exhumation and cooling, implying a limited influx of fluid. Hence, the localized metasomatism of the Bacariza Formation occurred prior to early Devonian Variscan HP-HT metamorphism due to infiltration of aqueous CO2-SO3-Ca-K rich fluids during the Cambrian volcanic-arc stage that formed the protoliths of this Formation or after its accretion to the margin of Gondwana, perhaps during the Ordovician rifting stage that affected this margin.
At the Geominero Museum (Spanish Geological and Mining Institute, Spanish National Research Council), important Spanish paleontological collections are preserved and safeguarded, among others. These collections were assembled from provincial geological surveys carried out by the Spanish Geological Map Commission since its establishment in 1849. This work discusses some of the results obtained from the reviews of mollusk and brachiopod collections conducted between 1996 and 2002. Professor Antonio Goy participated directly or indirectly in the reviews carried out in the 20th century, thereby contributing to the updating of taxonomy, correction of systematic or biostratigraphic attribution errors, as well as the geographic origin of the material.
In the Folded Middle Atlas belt, the Middle Jurassic sequence is often rich in brachiopods. A Bathonian section (Sidi L’Arbi) located 1 km northwest of the village of Boulemane has been studied. This section contains, in its upper part, immediately above a sandy limestone bed, two closely spaced stratigraphic levels rich in the lower Bathonian brachiopods and contains rare bivalves and gastropods. This brachiopod fauna is widely dominated by rhynchonellides, mainly the genera Kallirhynchia and Burmirhynchia. Five rhynchonellide taxa have been identified, which are: Burmirhynchia athiensis Rousselle, B. moulani Alméras, Kallirhynchia oranensis (Flamand) roussellei nov. subsp., K. oranensis (Flamand) guefaïtensis (Rousselle), and Cymatorhynchia reynesi (Oppel). Terebratulids are represented by three species: Holcothyris angulata Buckman, Ptyctothyris biplicata (Rousselle), and Lazithyris andjelkovici Radulović. Except Lazithyris andjelkovici, the other brachiopod species have a wide geographic distribution in the northern and southern (North Africa) margins of the western Tethys. Most of these taxa range from the late Bajocian to the early Bathonian. The silty marl and silty limestone facies of the two fossiliferous levels and the upper part of the section suggest a relatively shallow marine environment preceding the emersion, from the latest Bathonian, of all the Moroccan Jurassic basins located East of the Western Moroccan Meseta.
Lime mortars are used to establish the chronology of historic buildings. The process seems straightforward since atmospheric 14C is fixed into the calcite of the binder during the setting of the mortar. Nevertheless, the radiocarbon dating of mortars can present certain complications, leading to inconclusive dating results. Mineralogical studies are essential to select suitable samples for dating and avoid potential complications. Since the nature of the aggregates is a potential source of contamination the microtexture and mineralogy of the mortar components were determined using an optical polarising microscope (OM) on polished thin sections. The binder was analysed using Scanning Electron Microscopy (SEM) and the mineral composition was determined by powder X-ray diffraction (XRD), thermogravimetric analysis (TGA), micro-Raman analysis and Fourier Transform Infrared spectroscopy (ATR FT-IR). The most frequent complications faced by the authors during the radiocarbon dating of mortars were dolomitic, magnesian or impure limestone aggregates yielding layered double hydroxide (LDH) phases. The LDHs constituted a potential contaminant mineral phases for lime mortar radiocarbon dating preventing obtaining reliable ages. The results obtained in Castillo de Portilla (Álava) predate the historical period and the age discrepancy is related to the LDH content. The state of ruin of the building or the protection of built heritage could complicate the accurate sampling of lime mortar for radiocarbon dating. Rejuvenated ages at Irulegi Castle are attributed to the incorporation of inorganic carbon resulting from the recrystallization of the binder carbonates. The use of buried samples, as at San Juan de Barbadillo, can lead to rejuvenated ages due to the incorporation of recent organic carbon into the system.
Detailed studies on conodont biofacies from upper Frasnian to middle Famennian in the Compte section (Central Pyrenees area) allow recognition of different eustatic fluctuations and the Kellwasser, Nehden, and Condroz events. Five conodont biofacies have been identified: Palmatolepis, Palmatolepis–Polygnathus, Polygnathus–Palmatolepis, Palmatolepis–Icriodus and the new Icriodus–Palmatolepis biofacies. The evolution of conodont biofacies during the end Frasnian reflects a sudden regressive episode at the base of FZ13b subzone and a maximum transgressive trend at the top of FZ13b subzone, which aligns with the Upper Kellwasser Event. The Kellwasser crisis dramatically reduces the conodont biodiversity, which recovers during the lower Famennian. A transgressive trend is recorded during the Palmatolepis crepida–Palmatolepis gl. prima zone interval, which may be referred to as the Nehden Event. Within La Mena Formation two regressive trends are identified by sharp conodont biofacies changes in the Palmatolepis rhomboidea and Palmatolepis gr. gracilis zones: the lower and upper Condroz Events.
A combined structural, petrological, and anisotropy of magnetic susceptibility (AMS) study of the Cisuralian (285 ± 2 Ma) Cerro Redondo dacitic intrusion (Iberian Chain, NE Spain) has been conducted to reconstruct its emplacement kinematics and determine its 3D geometry at the outcrop scale. This small igneous body, covering only 0.17 km2, displays a well-defined magmatic foliation that is affected by asymmetrical, steeply plunging folds at different scales. Our multidisciplinary analysis suggests that the Cerro Redondo intrusion formed through the emplacement of successive magma pulses, during which the original magmatic foliations were passively folded. Detailed AMS data reveal a superposition of three kinematic processes recorded in the magnetic fabric, all occurring prior to complete crystallization: the development of an early planar magmatic fabric, localized simple shear deformation, and subsequent folding of the magmatic foliation. This integrated structural, petrological, and AMS study indicates that the Cerro Redondo intrusion is a sub-vertical, asymmetric subvolcanic body, emplaced at upper crustal levels under the control of extensional (or transtensional) movements of the late-Variscan Pardos Fault.
The Tafilalt Biota of southern Morocco has been shedding valuable light into the biodiversity and palaeoecology of the Upper Ordovician. The fossil remains of lightly-sclerotised discoidal organisms (eldonioids) are a common component among the Tafilalt assemblages preserved in sandstone. In this region, these non-biomineralised stem-group deuterostomes are widely distributed in the Upper Tiouririne Formation of eastern Tafilalt and in a relatively small area of northwestern Maïder, at the top of the First Bani Group. Within this stratigraphic range (Sa1–Ka3), the record is virtually restricted to a single species, Discophyllum peltatum Hall, which was locally described as ‘Eldonia berbera’ Alessandrello Bracchi, a junior synonym. Although D. peltatum is the most abundant “soft-bodied” organism of the Tafilalt Biota, the Moroccan material has not yet been the subject of a modern taxonomic revision. An important study on the African fossils, which formed part of a PhD Thesis submitted in 2012 at the University of Galway (Ireland), remains unpublished. Therefore, we deemed it necessary to revisit this topic and consolidate the knowledge of the Tafilalt Biota in the present study, while formalising the proposal of certain suprageneric taxa (Order Eldonida, nov., and Family Paropsonemidae, nov.) underpinning the classification of eldonioids.
The Moroccan Carboniferous orogenic formations are marked by numerous magmatic bodies associated with the evolution of the Variscan belt. Mafic rocks are interbedded within the Upper Visean detrital sediments, while granitoid bodies are late- to post-orogenic. The Khouribga–Oulmes structural unit, in the NE part of the Moroccan Central Hercynian Massif, features mafic rock series emplaced as layered sills and associated basaltic flows comparable to those of the Fourhal basin. This study focuses on the recently discovered Boucharmit sill, mainly composed of gabbros showing mineralogical and textural variations defining phase, size, or modal igneous layering. The petrographic study defines six gabbroic cumulate units dominated by plagioclase and clinopyroxene, with subordinate olivine, amphibole, and ilmenite. The study combines petrographic, mineralogical, and geochemical analyses with LA-ICP-MS trace element data on clinopyroxenes to constrain parental magma composition using appropriate partition coefficients. Main results include: six gabbroic units with olivine-bearing lenses at the bottom and pegmatitoid at the top; fractional crystallization following the olivine-plagioclase-clinopyroxene-amphibole-ilmenite sequence; late magmatism probably linked to hydrothermal fluids forming Ti–rich brown amphibole and ilmenite; cumulates geochemistry showing large element dispersion due to modal variations, not representing equilibrium melts; parental melts derived from a mantle source equilibrated in the spinel stability field; geochemical signatures indicating arc-related tectonic setting. These results are in agreement with models considering the Carboniferous basins at the NE of Moroccan Hercynian Central Massif as compressional foreland basins.
Detailed structural and geological mapping, along with the construction of deep cross-sections, focused on the border of a Mesozoic extensional basin (the Western Asturian Basin), has enabled the reconstruction of a complex evolution of the initial sedimentary infill. This evolution was driven by the reactivation of Variscan Paleozoic faults. The comprehensive surface and subsurface characterization of the basin was made possible through fieldwork and borehole data. Using these methods, five fault types have been identified: Variscan thrusts, Late Variscan right-lateral faults, Late Variscan thrusts, Mesozoic (Alpine) normal faults, and Cenozoic (Alpine) reverse and strike-slip faults. The Mesozoic faults commonly reactivated the Paleozoic faults during four extensional phases: Middle–Late Triassic, Early Jurassic, Late Jurassic, and Early Cretaceous. As a result of this reactivation, an asymmetric graben with complex geometry developed, controlled by the inherited Variscan and Late Variscan faults. Furthermore, this area has been demonstrated, for the first time, to represent the western boundary of a large Middle–Late Triassic rift basin, a boundary where extensional activity continued during the Early Jurassic, unlike in the inner Asturias Basin, where the extension almost stopped. The studied basin margin was partially inverted during the Eocene–Oligocene Alpine compression, leading to the reactivation of Paleozoic and Mesozoic faults with favorable orientations as reverse faults, and the development of associated open folds. Buttressing is also common, due to the geometry of most of the pre-existing faults.
Since ophiolites are remnants of ancient oceanic crust, which are later emplaced along convergent plate boundaries, they provide key insights into the magmatic and tectonic processes linked to mid-ocean ridges (MOR) and subduction zones, particularly in the Arabian Nubian Shield (ANS). This study presents an integrated mineralogical and geochemical investigation of ophiolitic metagabbros (MG) and metabasalts (MB) from two tectonically distinct regions of the Egyptian Eastern Desert: W. Um Qarati in the Central Eastern Desert (CED) and G. Gerf in the Southern Eastern Desert (SED). The Um Qarati rocks form part of a dismembered ophiolite thrust over an island arc assemblage, whereas the Gerf rocks preserve one of the most intact ophiolite sequences in the ANS. The primary mineral phases (plagioclase, hornblende, and clinopyroxene) are variably overprinted by greenschist to amphibolite facies metamorphism, as evidenced by secondary actinolite and chlorite. Plagioclase compositions in metagabbros range from oligoclase to labradorite with minor albite, exhibiting normal zoning in Um Qarati and reversed zoning in G. Gerf. Hornblende thermobarometry yields crystallization temperatures of 800–870°C and pressures of 3.99‒5.78 kbar. The presence of interstitial quartz, alongside apatite, and ilmenite points to a high degree of magma evolution. The studied metagabbros and metabasalts seem to represent a transitional stage between mid-ocean ridge (MOR) and island-arc tholeiitic (IAT) magmas. Their chondrite-normalised LREE patterns and HFSE ratios (Nb/Yb = 0.41–5.97 in MG and 0.74–11.47 in MB) suggest derivation from heterogeneous mantle sources ranging from depleted MORB-like to enriched OIB-like compositions. However, the negative Nb anomalies and high Th/Yb ratios in the metagabbros, point to metasomatic enrichment by slab-derived fluids and melts. The concentrations of immobile elements (Ti, V, Zr, Nb, and Y), along with structural features, including sheeted dykes and deformed pillow basalts, support a subduction initiation setting. In this context, early-stage extension and mantle upwelling generated MORB-type magmas, followed by progressive subduction-related input, yielding IAT-like compositions. The transitional geochemical character of the studied ophiolites closely resembles that of globally recognized subduction-initiation complexes, such as the Izu-Bonin-Mariana forearc and the Balkan Tethyan belt. These findings highlight the role of the Egyptian ophiolites as valuable analogues for understanding crustal generation during Neoproterozoic subduction initiation and early arc development.
The study of new collected, stratigraphically constrained ammonites from the uppermost Pliensbachian to Toarcian succession in three basinal sections of the Rich area (Central High Atlas, Morocco) allows refinement of the regional biochronostratigraphy for this interval and recognition of several unconformities with associated hiatuses of variable extent. Two of the sections (Azag and Ait el Abbas), located on the flanks of former diapiric anticlines, display relatively reduced thicknesses (110 and 91 m, respectively), whereas the Agounou section, situated within a syndepositional, halokinetic-related syncline (minibasin), is nearly seven times thicker. Hiatuses are identified by the absence or condensation of stratigraphic intervals ranging from ammonite subzones to entire stages. Ammonites from the Azag section enabled characterization of the Polymorphum, Levisoni, Bifrons, Gradata, Bonarelli, and Speciosum zones beneath an erosional surface capped by a condensed, decimetric-thick calcarenitic-conglomeratic bed with a ferruginous hardground of early Bajocian (Discites–Laeviuscula zones) age. This indicates a hiatus spanning at least the upper part of the late Toarcian to the Aalenian. In Ait et Abbas, the hiatus related to erosional truncation is even larger, encompassing at least from the Gradata Zone (Middle Toarcian) to the Aalenian. Moreover, the Semicelatum Subzone appears to be absent or only partially developed in the studied sections, suggesting an additional hiatus affecting the upper part of the Polymorphum Zone, as observed in other Tethyan and European sections. These hiatuses are interpreted as resulting primarily from erosion and/or sedimentary thinning toward diapiric highs, as well as from gravity-driven sliding related to the synsedimentary mobility of Triassic evaporites. The interplay of these regional halokinetic processes with supraregional tectonic events, climatic perturbations, and sea-level fluctuations shaped the stratigraphic evolution of the area. The chronostratigraphic framework and interpreted Toarcian–Lower Bajocian tectonosedimentary evolution of the Rich area are likely applicable to the Central High Atlas basin as a whole.
This communication analyzes the distribution of benthic foraminifera in the infralittoral zone of northern Chile located between 26° and 29°S at depths between 7 and 12 m. Twenty-six taxa have been identified, whose density is mainly conditioned by grain size and hydrodynamics of the environment. A comparison with other coastal sectors of the Pacific coast of South America allows us to identify the most representative species of this area from southern Chile to Colombia. The results obtained are very interesting for their possible application in the reconstruction of Holocene paleoenvironments in the Atacama Desert.
