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International audience; La question de la correspondance entre les caractéristiques cérébrales et endocrâniennes est cruciale pour les applications en paléoneurologie et n’a jamais été abordée. Pour ce faire, le projet PaleoBRAIN, financé par l’ANR (ANR-20-CE27-0009), va étudier pour la première fois la corrélation entre la forme du cerveau et celle de l’endocrâne au sein d’un échantillon d’humains actuels en utilisant des acquisitions par imagerie à résonance magnétique (IRM), dont certaines avec une séquence spécifique (UTE) qui permet la caractérisation des tissus osseux. Cette contribution sera décisive pour l’étude détaillée des informations neurologiques provenant d’humains fossiles. Nous reconstruirons ensuite le cerveau d’Homo erectus et le cerveau d’Homo neanderthalensis, ainsi que leurs schémas de croissance respectifs, en tenant compte des spécificités de ces espèces. Au-delà de l’analyse détaillée des relations cerveau-endocrâne pour améliorer notre compréhension de l’anatomie des hominines fossiles, plusieurs objectifs complémentaires sont abordés. Nous analyserons les modèles de variation et de corrélation entre asymétries cérébrales et crâniennes, dont celles concernant les structures internes. Nous aborderons aussi les éventuelles relations entre asymétries du cerveau et latéralisations comportementales sur le même échantillon de volontaires. Tous ces résultats, confrontés à la variation observée chez les hominines fossiles, vont documenter les connaissances sur l’évolution du cerveau et donc sur le lien généralement supposé entre forme et fonction. Nous présentons ici les méthodes, les grands axes de recherche et les premiers résultats de ce projet qui se terminera en 2025. La pluridisciplinarité et l’interdisciplinarité seront des composantes fortes de PaleoBRAIN ainsi que des conditions essentielles pour atteindre nos objectifs scientifiques. En outre, ce projet est engagé dans une politique de science ouverte : tous les ensembles de données d’imagerie virtuelle produits seront mis à la disposition d’autres scientifiques pour leurs recherches.

International audience; The group of large five-spotted Hemichromis species from West Africa and Lower Guinea was revised using an integrative approach combining morphometry (measurements, meristics and colour patterns) and genetics (cytochrome b gene). Specimens from 100 populations were sorted into three main groups on the basis of morphological criteria. Samples from Lake Bosumtwi clustered together with others from West Africa in a large well-supported clade (bootstrap values and posterior probabilities: 98/96/100), both in morphometric and genetic analyses, raising again the hypothesis of synonymy of H. frempongi with H. fasciatus. Samples from southern Lower Guinea, including the type locality (Gabon) of H. elongatus, constituted a second weakly resolved cluster (64/38/51), resulting from a potential admixture of populations of diverse origins which share common morphological traits. Populations from northern Lower Guinea (Atlantic coastal basins) and the upper Chad basin in Cameroon formed a third strongly supported clade (99/100/100), which corresponds to a new species, Hemichromis camerounensis sp. nov., herein described.

International audience; To survive in complex and seasonal environments, primates are thought to rely upon cognitive capacities such as decision-making and episodic memory, which enable them to plan their daily foraging path. According to the Ecological Brain hypothesis, feeding ecology has driven the expansion of the brain to support the corresponding development of cognitive skills. Recent works in cognitive neurosciences indicate that cognitive operations such as decision-making or subjective evaluation (which are contextual and dependent upon episodic memory), relied critically upon a small part of the frontal lobe, often referred to as the ventromedial prefrontal cortex (VMPFC). Several authors suggested that this area might be important for foraging, but this has never been tested. In the present study, we quantified the relation between the size of the VMPFC (along with other cerebral measures: the whole brain, the gyrus rectus and the somatosensory cortex) and key socio-ecological variables in five primate species (Macaca mulatta, Macaca fuscata, Gorilla gorilla, Pan troglodytes and Homo sapiens). We hypothesized that the size of the VMPFC would be greater in primates with a large dietary spectrum and complex foraging strategies. We also hypothesized that the impact of feeding ecology would be stronger on this specific region than on other regions (somatosensory cortex) or on more global cerebral measures (e.g., whole brain). In line with these hypotheses, we found that all cerebral measures were more strongly related to feeding ecology than group size, a proxy for social complexity. As expected, the VMPFC volume is more precisely related to feeding ecology than the whole brain, and appears to be critically related to dietary quality. Thus, combining a comparative approach with predictions coming both from behavioral ecology and cognitive neurosciences, our study provides evidence that feeding ecology played a key role in the development of specific cognitive skills, which rely upon the expansion of a specific cortical area.

The early Paleogene is critical for understanding global biodiversity patterns in modern ecosystems. During this interval, Southern Hemisphere continents were largely characterized by isolation and faunal endemism following the breakup of Gondwana. Africa has been proposed as an important source area for the origin of several marine vertebrate groups but its Paleogene record is poorly sampled, especially from sub-Saharan Africa. To document the early Paleogene marine ecosystems of Central Africa, we revised the stratigraphic context of sedimentary deposits from three fossil-rich vertebrate localities: the Landana section in the Cabinda exclave (Angola), and the Manzadi and Bololo localities in western Democratic Republic of Congo. We provide more refined age constraints for these three localities based on invertebrate and vertebrate faunas, foraminiferal and dinoflagellate cyst assemblages, and carbon isotope records. We find an almost complete absence of Danian-aged rocks in the Landana section, contrary to prevailing interpretations over the last half a century (only the layer 1, at the base of the section, seems to be Danian). Refining the age of these Paleocene layers is crucial for analyzing fish evolution in a global framework, with implications for the early appearance of Scombridae (tunas and mackerels) and Tetraodontiformes (puffer fishes). The combination of vertebrate fossil records from Manzadi and Landana sections suggests important environmental changes around the K/Pg transition characterized by an important modification of the ichthyofauna. A small faunal shift may have occurred during the Selandian. More dramatic is the distinct decrease in overall richness that lasts from the Selandian to the Ypresian. The Lutetian of West Central Africa is characterized by the first appearance of numerous cartilaginous and bony fishes. Our analysis of the ichthyofauna moreover indicates two periods of faunal exchanges: one during the Paleocene, where Central Africa appears to have been a source for the European marine fauna, and another during the Eocene when Europe was the source of the Central Africa fauna. These data indicate that Central Africa has had connections with the Tethyian realm. Keywords: Central Africa, Paleogene, Stratigraphy, Carbon isotope, Planktonic foraminifera, Vertebrates

The composition of melt inclusions in tourmaline was studied from graphic quartz-tourmaline intergrowth assemblages of common, muscovite – rare-element class pegmatites belonging to the lithium-caesium-tantalum family. This study applied laser ablation inductively coupled quadrupole mass spectrometry in combination with 2D and 3D microscopic volume calculation to analyse these unhomogenised melt inclusions. The determination of the analytical precision of the method is performed by repeated microscope-scanning and laser ablation analyses of tourmaline mineral inclusions in muscovite hosts for which the compositions have been independently measured by electron microprobe. The analysed melt inclusions are hosted in schorl-dravite series tourmaline from the early-Neoproterozoic pegmatite dykes of the Gatumba-Gitarama field in Rwanda. Multiple dykes have been studied, representing three regional pegmatite zones showing an increasing bulk regional degree of differentiation. The sampled graphic quartz-tourmaline assemblages are the only manifestation of an internal mineralogical zonation within these pegmatite dykes. The melt inclusions dominantly contain muscovite, quartz, dickite, feldspars, jeremejevite and childrenite minerals and variable amounts of Cs-rich, interstitial fluid. The major element composition of the ablated melt inclusions is variable but mainly plot on the low Ca-granitic compositional trend. The inclusions show, moreover, a significantly higher normative quartz content compared to bulk pegmatitic rock counterparts. The melt inclusions demonstrate a near-constant Rb concentration (100 up to 160 ppm) whereas Cs concentrations vary between 10 and 1000 ppm. Although Rb and Cs enrichment trends are accurate proxies to deduce pegmatite melt differentiation in general, both the Rb and Cs concentrations of the melt inclusions are remarkably unrelated to the regional degree of differentiation deduced from the constituent bulk rock and rock-forming minerals of the Gatumba-Gitarama pegmatites. A comparison of the alkali metal content of melt inclusions and cogenetic fluid inclusions with previously modelled bulk melt concentration indicates that this deviating Rb and Cs behaviour is caused by heterogeneous trapping of variable portions of the Cs-enriched aqueous fluid phase together with the residual melt and this during melt inclusion formation. The melt inclusions in tourmaline represent local and residual, hydrous boro-aluminosilicate melt compositions. The formation of graphic intergrowths inside the pegmatite dykes indicates rapid tourmaline growth rates causing in turn quartz saturation and nucleation in the surrounding residual melt. Fast tourmaline crystallisation contributed directly to the formation of these “melt pools” with distinct residual compositions. Our study shows that already for less-differentiated common pegmatites, melt inclusions from internal mineralogical zones represent closed melt subsystems that cannot be directly linked to the bulk system. These findings imply, moreover, that the use of tourmaline trace element compositions as an indirect geochemical proxy for the bulk melt composition of pegmatites and evolved granites, has to be considered with caution.

Studies dedicated to palaeoenvironments and taphonomy have made wide use of rare earth elements (REE) contents of fossil bones as proxies. However, the complex diagenetic history of individual specimens combined with intra-bone REE fractionation and the uncertain timing of REE uptake generally prevents the robust interpretation of REE patterns. In this case study we show that combining REE analysis with, on the one hand, histology and microstructural observations and, on the other hand, additional analyses of other trace elements, allows deciphering at least three distinct trace element uptake stages, as well as one leaching event. More than 35 trace elements (including the REE) are analysed using laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) within compact rostrum bones of the Miocene-Pliocene beaked whale Globicetus hiberus from deep-sea deposits and a comparable extant specimen (Blainville's beaked whale Mesoplodon densirostris). Comparison of the extinct and the extant bones allows a better quantification of the diagenetic trace element content. This study highlights the crucial role played by diagenetic minerals such as the Fe-Mn oxyhydroxides in the uptake and release of trace elements (Co, Ni, Ti, V, Zr, Hf and Nb) and REE by bones, in response to changes of the diagenetic fluid redox conditions over time. Such changes of the geochemical environment help constraining the post-mortem history of the bone and its interaction with diagenetic fluids. We conclude that the unique interpretation of geochemical proxies within individual fossil bones requires a thorough investigation of each individual specimen.

International audience; The Nefza mining district in Northern Tunisia comprises late Miocene (Serravallian to Messinian) magmatic rocks belonging to the post-collisional magmatism of the Mediterranean Maghreb margin. They are mainly made up of Serravallian granodiorite (Oued Belif massif), Tortonian rhyodacites (Oued Belif and Haddada massifs) and cordierite-bearing rhyodacites (Ain Deflaia massif) in addition to rare Messinian basalts. They are all characterized by LILE and LREE enrichment and strong enrichment in Pb and W. The Messinian basalts, which are also enriched in LILE, exhibit transitional characteristics between calc-alkaline and alkaline basalts. Geochemical (major and trace elements) and Sr, Nd and Pb isotopic compositions indicate that: (1) granodiorite is linked to the differentiation of a metaluminous calc-alkaline magma derived from a lithospheric enriched mantle source and contaminated by old crustal materials; (2) rhyodacites result from the mixing of the same metaluminous calc-alkaline magma with variable proportions of melted continental crust. Cordierite-bearing rhyodacite, characterized by the highest Sr-87/Sr-86 isotopic ratios, is the magma comprising the highest crustal contribution in the metaluminous-peraluminous mixing and is close to the old crustal end-member; (3) late hasalts, transitional between the calc-alkaline and alkaline series, originated from an enriched mantle source at the lithosphere-asthenosphere boundary. In the Nefza mining district, magmatic rock emplacement has enhanced hydrothermal fluid circulation, leading to the deposition of polymetallic mineralizations (belonging to the Iron-Oxide-Copper-Gold and the sedimentary exhalative class of deposits, among others). Magmatic rocks are also a source for the formation of lead (and probably other metals) in these deposits, as suggested by their Pb isotopic compositions. Magmatic rock emplacement and connected mineralization events can be related to the Late Mio-Pliocene reactivation of shear zones and associated lineaments inherited from the Variscan orogeny.

International audience; The Katanga Copperbelt region of the Democratic Republic of Congo hosts world-class cobalt deposits accounting for similar to 50% of the world reserves. Heterogenite (CoOOH) is the most abundant Co-bearing secondary mineral in the region. Its occurrence is the result of oxidation of Cu-Co-sulfides and associated Co reprecipitation in the uppermost part of the deposits, during the Pliocene. In addition to sediment-hosted copper and cobalt ore deposits, the Katanga Copperbelt also hosts numerous uraniferous mineral occurrences and deposits, which can be associated with heterogenite. Within these deposits, heterogenite can have high concentrations of U (up to 3.5%) and Pb (up to similar to 4%). In situ SIMS U-Pb ages were obtained for heterogenite samples from the U deposits of Shinkolobwe, Kalongwe and Kambove. These analyses yield distinct Neoproterozoic ages, at similar to 876 Ma, similar to 823 Ma and in the similar to 720 to similar to 670 Ma age range. As the geological context prevailing at those times was not favorable for heterogenite formation, these ages most probably record geological events that are not the formation of the mineral itself. For instance, the heterogenites could have inherited the U-Pb signature of a U-rich mineral, most likely uraninite, formed and/or yet reworked at similar to 876 Ma, similar to 823 Ma and in the similar to 720 to similar to 670 Ma time interval and spatially associated with primary Co-sulfides. In this hypothesis, the ages obtained in this paper are significant for understanding the cycling and re-deposition of U at given moments in the regional geological history. In such context, the similar to 876 Ma and the similar to 823 Ma age are consistent with syn-early diagenetic concentration of uranium in sediments of the Katanga basin. The similar to 720 to similar to 670 Ma ages are interpreted as a phase of U remobilization related to hydrothermal fluid circulation induced by late Nguba proto-oceanic rifting or by early stages of Congo-Kalahari craton convergence, and associated hydrothermal circulation.

International audience; The Pan-African Lufilian belt (Zambia and Democratic Republic of Congo) is known for its world-class copper and cobalt deposits. In addition, the Lufilian Copperbelt hosts several uranium occurrences concentrated within deformed siliciclastic rocks of the basal Neoproterozoic Katanga Supergroup. We report LA-ICPMS and EMP analyses of the rare earth element (REE) and yttrium (Y) abundances (designated as the REY signatures) of uranium oxides from two uranium mineralizing events of the Lufilian belt previously dated at 652 ± 8 Ma and 530 ± 6 Ma by the U–Pb method on uraninite. Uranium oxides dated at ca. 650 Ma from the External fold-and-thrust belt are characterized by (i) bell shape REE patterns centered on middle REE (MREE), (ii) positive europium (Eu) anomalies and (iii) relatively low Y contents. In contrast, uranium oxides dated at ca. 530 Ma from the Domes region are characterized by (i) REE patterns but with a less pronounced light REE (LREE) fractionation, (ii) negative Eu anomalies and (iii) higher Y contents. Moreover, the External fold-and-thrust belt also contains uranium mineralization dated at ca. 530 Ma having the same characteristics as the ca. 530 Ma uranium oxides from the Domes region (a moderately fractionated REE pattern and a negative Eu anomaly). As REY signatures are known to reflect mineralizing processes, the distinct geochemical signatures of the two uranium oxide generations (ca. 650 Ma and ca. 530 Ma) provide meaningful information about the uranium cycle during the Pan-African orogeny. Compared to the REY signatures of the known worldwide uranium deposit types, the REY signature of uranium oxides dated at ca. 650 Ma of the External fold-and-thrust belt is similar to the REE patterns from unconformity-related U deposits (Athabasca in Canada and Kombolgie in Australia). Uranium oxides of the Domes region and some of the External fold-and-thrust belt display similar characteristics to syn-metamorphic U deposit (Mistamisk in Canada). Accordingly, we propose that the two stages of uranium oxide crystallizations within the Lufilian belt, at ca. 650 and ca. 530 Ma, occurred under distinct physico-chemical conditions. The first stage, at ca. 650 Ma, may be related to late diagenesis hydrothermal processes, at the basement/cover interface, with the circulation of highly saline basinal brines linked to evaporites of the Roan Group. This Pan-African unconformity-related uranium deposit is the youngest of this type described to date. The second stage may be connected to metamorphic fluid circulations, at about 530 Ma, during the Lufilian orogeny in the Domes region and also in the External fold-and-thrust belt.

International audience; Alkaline massifs worldwide are generally atectonic. In Burundi, during the break-up of Rodinia, 700 Ma ago, the Upper Ruvubu Alkaline Plutonic Complex emplaced syntectonically. Large shear zones affecting the intrusion accommodated a regional NE-SW shortening in the regional extensional setting associated with Rodinia breakup. Magmatic dykes and magmato-hydrothermal mineralized veins strike NE-SW and have accommodated NW-SE stretching. C and O isotope characterization of the central Matongo carbonatite body attests for superimposed hydrothermal alterations, which induced REE and HFSE mobilizations on various scales.

Supergene manganese deposits commonly contain K-rich Mn oxides with tunnel structure, such as cryptomelane, which are suitable for radiometric dating using the 39Ar-40Ar method. In Africa, Mn deposits have been dated by this method for localities in western and southern parts of the continent, whereas only some preliminary data are available for Central Africa. Here we present new 39Ar-40Ar ages for Mn oxide samples of the Kisenge deposit, in southwestern Katanga, Democratic Republic of the Congo. The samples represent supergene Mn oxide deposits that formed at the expense of primary Paleoproterozoic rhodochrosite-dominated carbonate ores. Main phases of Mn oxide formation are dated at c. 10.5Ma, 3.6Ma and 2.6Ma for a core that crosses a mineralized interval. The latter shows a decrease in age with increasing depth, recording downward penetration of a weathering front. Surface samples of the Kisenge deposits also record a ≥c.19.2Ma phase, as well as c. 15.7Ma, 14.2Ma and 13.6Ma phases. The obtained ages correspond to distinct periods of paleosurface development and stability during the Mio-Pliocene in Katanga. Because Katanga is a key area bordered to the North by the Congo Basin and to the East by the East African Rift System, these ages also provide constraints for the geodynamic evolution of the entire region. For the Mio-Pliocene, the Kisenge deposits record ages that are not systematically found elsewhere in Africa, although the 10.5-11Ma event corresponds to a roughly simultaneous event in the Kalahari Manganese Field, South Africa. The rest of the Katanga paleosurface record differs somewhat from records for other parts of Africa, for which older, Eocene ages have been obtained. This difference is most probably related to the specific regional geodynamic context: uplift of the East African Plateau, with associated erosion, and the opening of the East African Rift System at c. 25Ma are events whose effects, in the study area, interfere with those of processes responsible for the development of continent-wide paleosurfaces.

International audience; The Matongo carbonatite intrusion belongs to the Neoproterozoic Upper Ruvubu alkaline plutonic complex (URAPC), that is located in Burundi along the western branch of the East African Rift. Beside the Matongo carbonatite, the URAPC alkaline complex comprises feldspathoidal syenites, diorites, quartz-bearing syenites and granites. Three main facies have been recognized in the Matongo carbonatite: (1) Sövites represent the dominant facies. Two varieties have been recognized. A scarce coarse-grained sövite (sövite I), which is altered and poorly enriched in REE (4 < ΣREE < 8 ppm), is encountered in highly fractured zones. A fine-grained sövite (sövite II), which is made of saccharoidal calcite, commonly associated with apatite, aegirine and amphibole, is abundant in the intrusion. Sövite II is enriched in LREE (442 < ΣREE < 1550 ppm, 49 < LaN/YbN < 175). (2) Ferrocarbonatites, that form decimeter-wide veins crosscutting the sövites, are characterized by a LREE enriched patterns (225 < ΣREE < 1048 ppm, 17 < LaN/YbN < 64). (3) K-feldspar and biotite-rich fenite facies (silicocarbonatites) have been recognized at the contact between the carbonatites and the country rock. They are likewise LREE-enriched (134 < ΣREE < 681 ppm, 25 < LaN/YbN < 46). Additionaly, "late" hydrothermal MREE-rich carbonatite veinlets can be found in sövite I. They are characterized by moderate enrichment in REE (ΣREE = 397 ppm), with a MREE-humped pattern (LaN/YbN = 3.7). The different facies represent the typical magmatic evolution of a carbonatite, while the silicocarbonatites are interpreted as resulting from the fenitisation of the country host-rocks. In addition, the most REE-depleted and fractionated facies, i.e. the coarse-grained sövite facies and the "late" calcite veinlets testify for hydrothermal processes that occurred after carbonatite emplacement and result from REE mobilization and redistribution. Large idiomorphic zircon crystals (megacrysts), found in the vicinity of the carbonatite can directly be related to the carbonatite evolution. They have been dated at 705.5 ± 4.5 Ma (U-Pb concordant age, LA-ICP-MS). Similar zircon megacrysts of the Lueshe carbonatite (DRCongo) have been dated and give a concordant age at 798.5 ± 4.9 Ma (U-Pb, LA-ICP-MS). Considering that an extensional tectonic regime occured at that time in Central Africa - what remains debated - both ages could relate to different stages of Rodinia breakup, with uprise of mantle-derived magmas along Palaeoproterozoic lithospheric zones of weakness.

The upper Miocene Oued Belif ring-shaped breccia is located in the Nefza mining district of northern Tunisia, within the internal zone of the collisional Alpine Maghrebide belt. It encloses chaotic Triassic material (evaporites, altered siltites, and pelites) within an extrusive diapiric structure reactivated in a late Miocene nappe emplacement episode. This deep-rooted structure drove the hydrothermal activity that caused the brecciation of the Oued Belif breccia and the emplacement of two generations of shallow felsic magmatism, which, most notably, include a Serravallian granodiorite stock and a Tortonian rhyodacite dome. The inverted cone-shaped matrix-supported Oued Belif breccia comprises clasts of Triassic material and others deriving from the regional substrate, as well as a very small amount of volcanic-related material that suggests a possible phreatomagmatic origin. Fine-grained, low-Ti, Si-Al-rich hematite (≥20 vol %) is the main matrix mineral, along with rare earth element (REE) minerals (bastnaesite, parisite, and subordinate monazite) and U minerals (uraninite). The Oued Belif breccia is not an economic Cu-Au deposit, although it does possess a distinct geochemical anomaly in mafic (Cu-Co-Au) elements, with local Cu enrichment at depth (from drill core material), as well as in felsic (Bi-W-Sn-U) elements. A multiphase alteration episode (K-Fe-(Mg) metasomatism) responsible for the formation of K-feldspar, Fe phlogopite, Fe muscovite, and tourmaline, with fluorite and barite, predates the Fe-light REE (LREE)-U mineralization. The major brecciation event occurred slightly after this alteration and is coeval with the main iron oxide-LREE-U mineralization event and the emplacement of the Oued Belif rhyodacite intrusion. Hydrothermal mineralizing fluids were hot (≥540°C), saline and F-CO 2-rich brines, possibly with a mixed, basinal (salt-related) and magmatic (alkaline-related) origin. Except for its lack of economic Cu and Au content, the Oued Belif breccia shares most typical attributes of the hematite group of iron oxide copper-gold (IOCG) deposits. One may therefore classify it either as an "iron oxide-associated-alkali-altered" (Porter, 2010) or as an "iron oxide uranium" (Skirrow, 2010) mineral system. K-Ar dating of K-feldspar sets the Oued Belif breccia formation at 9.2 ± 0.25 Ma, which could make it the youngest presently known representative of the iron oxide-associated-alkali-altered-IOCG class of deposits. From a geodynamic viewpoint, the Oued Belif structure fits within a still active collisional belt, even though the Oued Belif breccia was formed in a postcollisional stage. In this respect, Oued Belif differs from most other IOCG deposits, especially from older Proterozoic ones. It nevertheless shares two essential characteristics considered necessary to yield IOCG deposits (Skirrow, 2010), namely a metasomatized subcontinental lithospheric mantle and a lithospheric delamination process. Identifying the Oued Belif breccia as a member of the iron oxide-associated-alkali-altered-IOCG family opens new frontiers within the study of IOCG deposits within the geodynamic environment of collisional belts. Future research in this area should focus particularly on the circum-Mediterranean segment of the Alpine belt. © 2013 Society of Economic Geologists, Inc.

International audience; Major volcano flank collapses strongly affect the underlying magmatic plumbing system. Here, we consider the magma storage zone as a liquid pocket embedded in an elastic medium, and we perform numerical simulations in two-dimensional axisymmetric geometry as well as in three dimensions in order to evaluate the consequences of a major collapse event. We quantify the pressure decrease induced within and around a magma reservoir by a volcano flank collapse. This pressure reduction is expected to favor replenishment with less evolved magma from deeper sources. We also estimate the impact of the magma pressure decrease, together with the stress field variations around the reservoir, on the eruptive event associated with the edifice failure. We show that, for a given magma reservoir geometry, the collapse of a large strato-volcano tends to reduce the volume of the simultaneous eruption; destabilization of large edifices may even suppress magma emission, resulting in phreatic eruptions instead. This effect is greater for shallow reservoirs, and is more pronounced for spherical reservoirs than for vertically-elongated ones. It is reduced for compressible magmas containing a large amount of volatiles. Over a longer time scale, the modification of pressure conditions for dyke initiation at the chamber wall may also explain an increase in eruption rate as well as an apparent change of magma storage location.

International audience; The study of endocranial asymmetries of hominids is a central topic in paleoneurology. However, our knowledge about the emergence of these asymmetries during human evolution is still limited. This is partly due to the fact that, so far, these 3D asymmetries have been mostly analyzed using landmarks-based methods. Such methods are limited as they only provide a partial description of the anatomy and thus of the possible asymmetries. The endocranial anatomy may be better described by its whole contour, and the recent advent of computational tools allowing to process 3D free-form surfaces opens new tracks for automated and objective characterization of 3D endocranial asymmetries. One key problem before assessing the evolution of patterns of asymmetry in hominids is the identification of confounding factors such as age, sex and intra-specific variability. For this purpose, we use a new method for the automated quantification of 3D virtual endocranial shape of 60 Pan paniscus and 59 Pan troglodytes of different dental age and sex. 3D statistical analyzes are led to assess significantly asymmetrical areas on the endocasts within each population, and a comparison is made between the two populations. Several fossil hominin endocasts (such as Australopithecine species and fossil Homo species) are then reexamined in light of the previously estimated variability with these two extant Pan species. These new computational tools may offer a new way to address the question of how the typical endocranial asymmetries within modern humans (e.g. protrusions of the frontal and occipital lobes) emerged during evolution.

The Katanga Copperbelt, in the southeastern part of the Democratic Republic of the Congo (DRC), occurs within the Pan-African Lufilian fold-and-thrust belt and hosts numerous uraniferous mineral occurrences in addition to the world-class sediment-hosted copper and cobalt ore deposits. In the 1950s and 1960s, Cahen et al. gave a relatively wide range of U mineralization ages, using U–Pb dating on whole-rock samples. Although these ages nowadays appear as inaccurate because of large error ranges, they were frequently used to discuss the regional geodynamic events. This paper offers a reappraisal of the age range previously published, using in-situ SIMS U–Pb analyses. Based on these analyses, two ages are regarded as analytically reliable and significant (652.3 ± 7.3 Ma and 530.1 ± 5.9 Ma), and hence as having implications for the understanding of geological and geodynamic context in the study area. In the Katanga Copperbelt, the siliciclastic rocks of the Lower Roan Group are slightly enriched in uranium. A major U mineralization/(re-)mobilization episode took place at ~ 652 Ma, during proto-oceanic rift basin development. This phase took place in an extensional tectonic regime and led to the (re-)mobilization of U within fractures and voids. Such deposits are observed along the ~ 250 km-long Kalongwe–Luishia tectonic lineament. This metal concentration was reworked at ~ 530 Ma, at the occasion of the climax of Lufilian deformation and metamorphism. This event gave rise to the U deposits in the southern border of the Katanga Copperbelt (and in Northern Zambia). The Kolwezi deposit is a deposit located further to the North. Notwithstanding its initial position further to the south, the deposit is heavily faulted and the thrusts and faults could have focused the fluids associated with the deformation, at ~ 530 Ma.