Camille François

Commission for the Geological Map of the World (CGMW)

Understanding processes of formation of accretionary wedges requires studying young and well preserved examples. The Lengguru wedge (West Papua) is younger than 10 Myr and is a result of oblique and fast subduction (11 cm/yr) of the Bird's Head (a part of the Australian margin beneath the Melanesian Arc). Thus, the rapid formation of this wedge (ac...

In this paper, we present new age constraints for the lower part of the Meso-Neoproterozoic sedimentary Mbuji-Mayi Supergroup (Democratic Republic of Congo, DRC). This Supergroup preserves a large diversity of organic-walled microfossils, evidencing the diversification of early eukaryotes for the first time in Central Africa. We use different metho...

Knowing which geodynamic regimes characterised the early Earth is a fundamental question. This implies to determine when and how modern plate tectonics began. Today, the tectonic regime is dominated by mobile-lid tectonics including deep and cold subduction. However, in the early Earth (4.5 to 2 Ga) stagnant-lid tectonics may also have occurred. Th...

Orogens develop in convergent settings involving two or more continental and/or oceanic plates. They are traditionally defined as zones of crustal deformation associated with mountain building resulting from either accretion of a terrane and/or an arc, continent-continent collision or rift-inversion. However, this definition does not consider the g...

Ultraviolet (UV)-screening compounds represent a substantial asset for the survival of cyanobacteria in extreme environments exposed to high doses of UV radiations on modern and early Earth. Among these molecules, the halochromic pigment gloeocapsin remains poorly characterized and studied. In this study, we identified a gloeocapsin-producing culti...

The acquisition of photosynthesis is a fundamental step in the evolution of eukaryotes. However, few phototrophic organisms are unambiguously recognized in the Precambrian record. The in situ detection of metabolic byproducts in individual microfossils is the key for the direct identification of their metabolisms. Here, we report a new integrative...

Des datations et des concepts plus précis sur les déformations crustales en extension et en compression permettent actuellement d’appréhender l’évolution spatio-temporelle des discordances stratigraphiques et donc les pics de déformation. Les marges continentales, bien documentées par la sismique réflexion montrent que l’extension et la rupture con...

Knowing the geodynamic processes of the Early Earth is not only crucial to understand the evolution of our planet but also because they have strong implications for its habitability. Today, the modern Earth geodynamics is governed by plate tectonics (mobile-lid tectonics). Precambrian Earth, however, had different thermal, rheological and lithologi...

Orogens are classically thought to develop in a convergence context involving two or more plates of continental and/or oceanic nature. They are defined as deformed crustal areas with topographic building developing from either arc-continent subduction, continental collision or inverted rift basins. However, this definition does not take into accoun...

One of the great puzzles of Earth's geodynamics is to determine when rigid plate tectonics (as we know it today), began on Earth and what geodynamic processes existed on early Earth. This implies to constrain the evolution of these processes over time, to know if the transition from an ancient tectonics to a modern tectonics happened quickly, by ep...

Orogens develop in convergent settings involving two or more continental and/or oceanic plates. They are traditionally defined as zones of crustal deformation associated with mountain building resulting from either accretion of a terrane and/or an arc, continent-continent collision or rift-inversion. However, this definition does not consider the g...

Orogens form in convergence settings involving two or more continental and/or oceanic plates. They are traditionally defined as zones of crustal deformation associated with mountain building resulting from either the accretion of an arc, a continent-continent collision or the inversion of a rift basin. However, this somewhat narrow definition does...

A l'occasion des Journées Nationales de la Géologie, la CCGM vous propose un atelier/conférence pour (re)découvrir la Charte Stratigraphique Internationale, la Carte Géologique du Monde et le Globe Géologique terrestre. L'objectif est essentiellement pédagogique (la Carte Géologique du Monde figure au programme de SVT de 1ère et Terminale S) et vo...

The Indian Ocean has witnessed some of the most important geodynamic events that shaped our present-day Earth during the last plate tectonic episode. From the early fragmentation of the Gondwana super-continent sustained by an intense hotspots activity to the real-time birth of a new volcano in 2019 in the Comoros Archipelago, almost 200 Myr of geo...

Because of the outbreak of the global Covid19 pandemic, the 36th IGC scheduled between March 2nd and 8th, 2020 had to be cancelled and postponed to August 2021. Along with this event was our CGMW General Assembly and our Bureau Meeting. As some members of our community were not in the position to reschedule their journey, we have chosen to postpone...

On the basis of phylogenetic studies and laboratory cultures, it has been proposed that the ability of microbes to metabolize iron has emerged prior to the Archaea/Bacteria split. However, no unambiguous geochemical data supporting this claim have been put forward in rocks older than 2.7–2.5 giga years (Gyr). In the present work, we report in situ...

Important biological and geological events occurred during the early to middle Neoproterozoic. Among diversifying eukaryotic assemblages, populations of Cerebrosphaera, a distinctive and robust organic-walled vesicular microfossil (acritarch), show restricted stratigraphic distribution in several late Tonian to early Cryogenian worldwide succession...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Fungi are crucial components of modern ecosystems. They may have had an important role in the colonization of land by eukaryotes, and in the appearance and success of land plants and metazoans1–3. Nevertheless, fossils that can unambiguously be identified as fungi are absent from the fossil record until the middle of the Palaeozoic era4,5. Here we...

Cyanobacteria played an important role in the evolution of Early Earth and the biosphere. They are responsible for the oxygenation of the atmosphere and oceans since the Great Oxidation Event around 2.4 Ga, debatably earlier. They are also major primary producers in past and present oceans, and the ancestors of the chloroplast. Nevertheless, the id...

The main rationale of the IGCP 667 project is to perform a map (1/10 000 000) of world (ancient and modern) orogens and to represent them along the geological history of the Earth. Therefore, the definition of an orogen is critical and obliges us to go back to the fundamentals of geology by identifying the key elements of an orogen and place them a...

Understanding the geodynamic processes of the Early Earth is crucial because they have strong implications for the habitability of the Earth but also for other planets. The Earth is the only proven planet in the solar system displaying lithospheric plate tectonics. However, plate tectonics on Earth did not always function as today, and the Archean...

We report for the first time the petro-geochemical study and the emplacement age of the Flamanville granitoid pluton, which is one of the most pedagogical and frequently visited granitoid in France. This study shows that it consists of a potassic alkaline to calc-alkaline and metaluminous granodiorite with biotite, hornblende and pluri-centimetric...

Knowing which geodynamic regimes characterised the early Earth is a fundamental question. This implies to determine when and how modern plate tectonics began. Today, the tectonic regime is dominated by mobile-lid tectonics including deep and cold subduction. However, in the early Earth (4.5 to 2 Ga) stagnant-lid tectonics may also have occurred. Th...

Since the Archean (between 4 to 2.5 Gyr ago) was much hotter than the present time because of higher rates of internal heat production, it is traditionally accepted that the mantle was convecting faster, resulting in faster mixing time and also plates at the surface of the Earth moving faster. Short-lived isotope systems are particularly adapted to...

Knowing the plate tectonic regime of the early Earth is a fundamental but ongoing question and its resolution implies to know when and how plate tectonics and subduction began on Earth. Today, the tectonic regime is ruled by mobile-lid tectonics including subduction. However, in the early Earth stagnant-lid tectonics (or sagduction) could also occu...

The question of how and when plate tectonics and subduction processes initiated on Earth is still a subject of debate. Subduction requires the oceanic lithosphere to sustain differential stress without creep. Today, mid-to high-pressure mineral assemblages are commonly interpreted in terms of plate tectonic processes including subduction. While in...

Sedimentary rocks containing microfossils are crucial archives to reconstitute early life evolution on Earth. However, the preservation of microfossils within rocks depends on several physico-chemical factors. Among these factors, the thermal evolution of the host rocks can be decisive. Here, we investigated carbonaceous shale samples containing ex...

Evaluate the thermal maturity of old sedimentary basins containing microfossils is crucial to reconstruct early life evolution on Earth. Here, we investigate carbonaceous shale samples containing exquisitely preserved organic-walled microfossil assemblages from three Proterozoic shallow marine sedimentary sequences: the Mbuji-Mayi Supergroup (Democ...

We report for the first time the petro-geochemical study and the emplacement age of the Flamanville granitoid pluton, which is one of the most pedagogical and frequently visited granitoid in France. This study shows that it consists of a potassic alkaline to calc-alkaline and metaluminous granodiorite with biotite, hornblende and pluri-centimetric...

The Lengguru wedge in West Papua is younger than 10 Myr and is a result of oblique and fast subduction (11cm/yr) of the Bird's Head, a part of the Australian margin beneath the Melanesian Arc. Thus, the formation of this wedge, recently and very rapidly, may be attributed to a single tectonic event. High pressure (HP) metabasic and metased-imentary...

The Mbuji-Mayi Supergroup, DRC, is located between the Archean-Paleoproterozoic Kasai Craton and the Mesoproterozoic Kibaran Belt. This sedimentary sequence is unaffected by regional metamorphism and preserves a large diversity of well-preserved microfossils, evidencing the evolution of complex life (early eukaryotes) for the first time in Meso-Neo...

The Interuniversity Attraction Pole (IAP) ‘PLANET TOPERS’ (Planets: Tracing the Transfer, Origin, Preservation, and Evolution of their Reservoirs) addresses the fundamental understanding of the thermal and compositional evolution of the different reservoirs of planetary bodies (core, mantle, crust, atmosphere, hydrosphere, cryosphere, and space) co...

The Mbuji-Mayi Supergroup, DRC, is located between the Archean-Paleoproterozoic Kasai Craton and the Mesoproterozoic Kibaran Belt. This sedimentary sequence, unaffected by regional metamorphism, preserves a large diversity of well-preserved microfossils, evidencing the evolution of complex life (early eukaryotes) for the first time in Meso-Neoprote...

A well preserved and diversified microfossil assemblage is reported from the Meso–Neoproterozoic Mbuji-Mayi Supergroup in the Kasai oriental Province, central part of Democratic Republic of Congo. A total of 49 taxa belonging to 27 genera were identified, including 11 species of unambiguous eukaryotes, 10 species of possible eukaryotes or prokaryot...

The Mbuji-Mayi Supergroup is a sedimentary sequence in DRC unaffected by regional metamorphism. It consists of two distinct successions: a lower, ∼500 m thick siliciclastic sequence of the BI Group and an upper, ∼1000 m thick carbonate sequence with stromatolitic build-ups and black shales of the BII Group directly overlain by basaltic lavas [1]. R...

The Mbuji-Mayi Supergroup is a sedimentary sequence in DRC unaffected by regional metamorphism [1]. It consists of two distinct successions: a lower, ~500 m thick siliciclastic sequence of the BI Group (dated at 1125 Ma [2] or between ca. 1175 Ma and 882 Ma [3]) and an upper, ~1000 m thick carbonate sequence with stromatolitic build-ups and black s...

The Sankuru-Mbuji-Mayi-Lomami-Lovoy (SMLL) basin, DRC, located between the Archean-Paleoproterozoic Kasai Craton and the Mesoproterozoic Kibaran Belt, includes the Mbuji-Mayi Supergroup, a sedimentary sequence unaffected by regional metamorphism and containing a large diversity of well-preserved acritarchs [1]. Lithostratigraphically, this Su...

Archaean granitic domes and intervening greenstone basins are often interpreted in terms of sagduction, a process which corresponds to the gravitational sinking of surficial greenstone covers and coeval exhumation of deeper granitic crust into broad domes. Alternatives models that can account for the regional dome and basin pattern include fold int...

The interpretation of high-grade rocks in the Archean is controversial. Mid- to high-pressure assemblages are commonly interpreted in terms of plate tectonic processes including subduction. In the Archean however, mid- to high-pressure assemblages could have been also produced during the sagduction of greenstone covers into their crustal basement....

High pressure metasediments together with retrogressed eclogites and migmatites have been found in the internal part of the Lengguru prism (Wandamen peninsula, W-Papua). The tectonic context is very active in this area with convergence rate between Australia and Caroline plates that reach 11 cm/yr. Our tectonic study (Bailly et al., 2009) shows tha...