The Quaternary millionth map of metropolitan France proposed here presents the geological polygons of Quaternary-age formations of metropolitan France as well as certain remarkable sites (prehistoric, of climatic interest, paleontological, palynological) that have been the subject of a comprehensive study over the past 20 years.
The polygons are RGF (Geological Referential of France) labeled and the RGF chronostratigraphic charter (compatible with the INSPIRE standard) was used for the chronological attributions. The map has been updated according to recent modifications of the international stratigraphic chart.
This map will in the end be integrated into the next map of the European Quaternary at 1 / 2,500,000 (IQuaME)
4-day training course in geochronology from 8 till 11 October 2019
The first three days (Tue-Thu) involve training on geochronological techniques and age-depth modelling given by experts in the field. The theoretical part will be followed by a field excursion on Friday, where sampling techniques for C-14, OSL, ESR, and CRN dating will be presented and discussed.
MSc and PhD students in geo-sciences and archaeology, as well as early career and advanced researchers and professionals are welcome in this geochronology training course. The full course qualifies for 30 contact hours or 4 ECTS. It is possible to participate in part (15h or 2 ECTS) of the training program. A certificate for the doctoral school can be issued on request.
Dedicated to the publications of the Q11 symposium held in Orléans in 2018, it first takes us to the Bao Bolon Valley in Senegal for a paleoenvironmental study of the second half of the Holocene (Stern et al., 2019). Back in France, in the Somme Valley, paleontological and geochronological data allow a reinterpretation of the archaeological site of Menchecourt (Bahain et al., 2019). Which large animals lived in the vicinity of the Neandertal occupations of the Ramandils cave (Port-la-Nouvelle, Aude, France)? Rush et al. (2019) study their assemblages to reconstruct the palaeoenvironmental and paleoclimatic framework during the Late Pleistocene.
Two articles are devoted to the region of Orleans which hosted the Q11 symposium. Coussot et al. (2019) describe the chronostratigraphy of the filling of a palaeovallon by silt in the context of the Beauceron plateau at Courville-sur-Eure (Eure-et-Loir, France), which extends from the second half of the Middle Pleistocene to the Holocene. From a sedimentary filling section at the prehistoric site of La Roche-Cotard IV (Indre-et-Loire, France), Marquet et al. (2019) conclude that the parietal productions with a symbolic character of the cave are very probably the work of the Neanderthal Man.
Finally, Armynot of Châtelet et al. (2019) have characterized foraminifers to reconstruct the environment of the Merovingian and Carolingian emporium of Quentovic, in the mouth of the Canche (France).
You can read a more detailed introduction of this issue and the Q11 colloquium in the foreword (Tissoux and Jacob, 2019).
An international research group, including scientists from three French laboratories (1), has revealed the systematic and negative impact of ocean warming on the extent of ice shelves in the East Antarctic Peninsula in recent decades and the 9000 last years.
The Antarctic Peninsula is one of the regions most affected by the current global warming. Over the last 50 years, it has lost almost 75% of the surface of its floating ice platforms, which are important barriers to ocean erosion for the continental ice cap and, therefore, limit the sea-level increase. The major collapses of these platforms in recent decades coincide systematically with joint and rapid increases in ocean temperature (+0.3°C) and atmospheric temperature (+3°C).
Scientists conducted geochemical analysis of marine sedimentary records which were compared to data from an ice core located only 50km from their study site. With these temperature reconstructions covering the last 9000 years, they have shown that the main period during which all the platforms have been greatly reduced in the Eastern Antarctic Peninsula, between 8200 and 6000 years BC, occurred during a major oceanic warming (+1.5°C) period, while the atmosphere was cooling. They also pointed out that the progressive warming of the ocean (+0.3°C) over the last thousand years has recurrently controlled the gradual removal of the ice shelves of this region.
Based on this observation, this research team focused on assessing the possible evolution of ocean and atmospheric temperatures over the next century, based on two scenarios established by the Intergovernmental Panel on Climate Change (IPCC). Only the pessimistic scenario of increasing atmospheric (+3°C) and oceanic (+0.3°C) temperatures would be enough to weaken these ice platforms even more, until they can collapse completely in the coming decades. Their future therefore belongs henceforth to the respect or not of the Paris Agreements, and to its objectives of limiting global warming to +2°C.
The French laboratories involved are the Laboratoire environnements et paléoenvironnements océaniques et continentaux (EPOC/OASU, Université de Bordeaux/CNRS/EPHE), the Laboratoire d’océanographie et du climat: expérimentations et approches numériques (LOCEAN/IPSL, CNRS/UPMC/IRD/MNHN), and Unité mixte internationale TAKUVIK (UL/CNRS).
The pollen grains content of lacustrine sediments allowed to trace the history of mountain biomes in Cameroon during the last 90 000 years. This study, conducted by French laboratories LOCEAN and LSCE of the IPSL with the National Herbarium of Cameroon, showed that tropical mountain forests are extremely vulnerable to climate change.
Because they have forms and ornamentations that are specific to most plant species and are remarkably preserved in sediments, pollen grains are powerful tools for reconstructing the vegetation of the past and understanding biodiversity.
Bambili Lake, located on the volcanic line of Cameroon at an altitude of 2273m, has provided a unique palynological sequence in tropical Africa, the first that accurately covers such a long period, ie most of the last climatic cycle. This sequence makes it possible to precisely follow the response of mountain biomes to extreme climatic, glacial and interglacial situations.
The study shows that Cameroon’s mountain forest biome has been extremely sensitive to climate change in contrast to lowland forests that appear to have been much more stable. Its area has varied considerably over time, in particular because of the large movements of its upper limit. This ecological instability has not been a hindrance to the exceptional biodiversity of the high mountains of Cameroon, but has instead favored it.
Analyzes performed on the teeth of two Neanderthal children from the archaeological site of Payre (Ardèche) and excavated by Marie-Hélène Moncel, CNRS researcher, attest to the oldest exposure to lead in humans. An international team of researchers measured the metal levels in the enamel of these teeth, dating back around 250,000 years, and showed that both children had been exposed to lead during their stays in cavities as suggested by the presence of lead mines within a radius of 25 kilometers. With teeth growing at the same rate as tree rings, researchers were able to show that children became ill during the cold season, and that one of the Neanderthals was born in the spring. By measuring barium concentrations, a marker of milk consumption, the researchers also found that one of the two children had been breastfed for up to two and a half years, and weaned in the fall. The study published on October 31, 2018 in Science Advances is a major contribution to Neanderthal childhood knowledge.
Wintertime Stress, Nursing, and Lead Exposure in Neanderthal Children. Tanya M. Smith, Christine Austin, Daniel R. Green, Renaud Joannes-Boyau, Shara Bailey, Dani Dumitriu, Stewart Fallon, Rainer Grün, Hannah F. James, Marie-Hélène Moncel, Ian Williams, Rachel Wood, Manish Arora. October 31st, 2018, Science Advances. DOI : 10.1126/sciadv.aau9483
An international team(1) modeled the coupling between the extent of sea ice and marine ice shelves, and the temperature of the waters near the North Atlantic surface. This model explains the steep temperature changes in Greenland and the North Atlantic during the last ice age, between 130,000 and 15,000 years ago. It also reproduces the phase shift between the temperatures of the two hemispheres during this period, as estimated from measurements in ice cores in Greenland and Antarctica. This work should help assess the risk of such abrupt changes in the near future.
The last glacial interval was marked by abrupt climatic changes called Dansgaard-Oeschger (DO) events. These events, characterized by significant temperature increases over Greenland up to 15°C in a few decades and a return to glacial conditions over several centuries, have been repeated many times during the last glacial cycle. However, the cause of these transitions and their out-of-phase relationship with corresponding events in Antarctica remains unclear. Indeed, a satisfactory theory of the Dansgaard-Oeschger cycles was still missing.
The team built a dynamic model to explain these DO events in Greenland, but also their counterparts observed in Antarctica. This model focuses on the interactions between ice sheets from the northern hemisphere ice caps (and more specifically Greenland), sea ice and ocean currents. It demonstrates that the repetitive nature and speed of the warming phase of DO events is based on the rapid retreat and slower regeneration of thick marine ice platforms, several hundred meters, and the much thiner sea ice, only a few meters around the caps of the northern hemisphere.
Variability of the last glacial interval as expressed by changes in oxygen isotope ratio (18O) obtained from two ice cores: blue in Greenland (NGRIP-North GReenland ice core project) and orange in Antarctica (WAIS ice core – West Antarctic ice sheet divide project). Age in thousands of years before the year 2000.
The proposed model successfully replicates the observed characteristics of changes in the oxygen isotope ratio, such as the sawtooth form of DO cycles (with sudden warming and slower cooling to glacier conditions), the intervals between successive DOs during the last 130 000 years, and also the phase shift of the climate signal observed in the ice cores of Greenland and Antarctica: when Greenland warmed, Antarctica cooled, and conversely, the abrupt warmings observed in Greenland not having their counterparts in Antarctica.
In addition, this study provides an explanation for abrupt climate changes and could thus help to more accurately assess the risk of abrupt climate transitions in the near future.
(1) Laboratories and institutes involved: Laboratoire de météorologie dynamique (LMD/IPSL, CNRS / ENS / École Polytechnique / Sorbonne Université), Potsdam institute for climate impact research (Germany), Grantham institute (Imperial college, UK), University of California (USA) and Columbia University (USA)
Boers, Niklas, Michael Ghil and Denis-Didier Rousseau. ”Ocean circulation, ice shelf and sea ice interactions explain Dansgaard-Oeschger cycles”. Proceedings of the National Academy of Sciences USA (2018) www.pnas.org/cgi/doi/10.1073/pnas.1802573115
Most models of climate simulations and vegetation indicate that ongoing climate change will have a global and far-reaching impact on terrestrial species and ecosystems for decades to come. Field observations would probably give researchers more confidence in future projections and thus allow more appropriate decisions to be made. An original approach has been implemented based on the observations and expertise of over 40 paleoecology researchers around the globe.
Each researcher assessed changes in ecosystem structure and composition during the transition from the last ice age, centered around 20,000 years ago to about 14,000 years ago, in fossil sequences in his study area. These fossil recordings represent a unique and invaluable archive and provide concrete observations of the relationship between global climate change and the composition and structure of ecosystems. The chosen period of time is very interesting in terms of increasing temperatures and changing ecosystems on a global scale even if it can not be considered as analogous to the expected climate changes, in particular because of the concentrations of CO2 that were weaker than currently.
This expert-based approach examined several hundred published paleoecological records to assess changes in the composition and structure of global terrestrial vegetation. The synthesis of the results published in the journal Science and their comparison with simulations shows that in the case of the RCP2.6 scenario (temperature increase of about 1.5 ° C, in line with that of the Paris Agreement of 2015) the impact would be limited but in the case of the RCP8.5 scenario, terrestrial ecosystems would be strongly threatened by rising temperatures and most ecosystems would risk profound and irreversible changes such that ecosystem services and biodiversity would be irretrievably affected.
Researchers from the Institut des Sciences de l’Évolution de Montpellier, the Institut méditerranéen de biodiversité et d’écologie marine et continentale, the Centre européen de recherche et d’enseignement de géosciences de l’environnement and the Laboratoire d’océanographie et du climat were involved in this study.
French and Italian research teams have analyzed by X-ray scans the oldest human teeth discovered on the Italian peninsula. These specimens, some 450,000 years old, from the Italian sites of Fontana Ranuccio, 50km from Rome, and from Visogliano, less than 20km from Trieste, already show Neanderthal characteristics. The study conducted by Clément Zanolli, paleoanthropologist at Toulouse III University, has just been published in the journal PLOS One.
The history of the Neanderthals is still unknown, especially in the earliest period of their development, from the time their lineage splits from ours around the transition from the Lower and Middle Pleistocene (between 1 million years and about 650,000 years ago), to the emergence of classical Neanderthals less than 200,000 years ago. One of the key periods for understanding the origin of Neanderthals is thus between 500,000 and 350,000 years ago.
An international collaboration involving French and Italian researchers allowed to study the internal structure of dental remains from these two Italian sites using high-resolution imaging methods. X-ray microtomography analysis of various parameters such as the proportions of the dental tissue, the thickness of the enamel, the morphology of dentin and pulp cavity allowed to highlight some characteristics commonly found in Neanderthals, which clearly differ from those specific to modern humans. The results suggest a demographic division and more or less prolonged periods of isolation. One of the important factors to consider is the climate. 450,000 years ago, northern Europe was covered by ice, and northern Spain and Italy had to be at the northern limit of habitable areas.
Valérie Masson-Delmotte, paleoclimatologist at the French Laboratory for Climate and Environmental Sciences (LSCE), is co-chair of the IPCC’s (Intergovernmental Panel on Climate Change) Working Group on Climate Physical Basis. Following the publication of a special report on the impacts of a global warming of 1.5°C, she was auditioned in the Senate. A video of her testimony and the questions and answers that followed is available on the Senate website.
In a 13-minute presentation, she summarizes in very accessible and educational terms the construction and conclusions of this report. It was prepared following a request from COP 21, arising from countries most vulnerable to global warming. This report has an unprecedented interdisciplinary dimension in the drafting of each of its chapters. It includes two very innovative chapters on action options and the benefits of acting now towards sustainable development goals.
The four key messages of the report are the following :
Climate change is already affecting people, ecosystems and livelihoods everywhere
There are undeniable advantages in limiting global warming to 1.5°C compared to 2°C or more, and every half degree counts
Limiting global warming to 1.5°C is not impossible but would require unprecedented transitions in all aspects of society and political will is crucial
Limiting global warming to 1.5°C can go hand in hand with achieving global sustainable development goals for improving the quality of life for all
Valérie Masson-Delmotte concludes her intervention with this message:
Every half degree counts, with respect to climate risks. Each year counts, with respect to the consequences in order to control climate change. Every decision counts. Not to act today is to increase the burden on younger generations who will have to deal with the consequences of global warming and the deployment of more difficult and riskier actions. Limiting global warming to 1.5°C is not impossible, but the political will to accelerate transitions is essential.
This intervention is followed by an in-depth discussion, which notably evokes alarmism, and the need for courage, the production of knowledge on the local impacts of global warming, the local to global action options, the links relating climate – health – sustainable development – eradication of extreme poverty – demography. Energy trajectories. The individual and collective responsible choices. The functioning of the IPCC and its role vis-à-vis the political community and the actors of change. Vulnerable countries and regions. The role of education and the mobilization of youth.
The detection, thanks to Lidar technology, of thousands of Mayan ruins in northern Guatemala was revealed last January. Their extensive analysis was published on September 28, 2018 in the journal Science by an international collaboration in which two French researchers, a CNRS archaeologist and a geographer from the University Paris 8 Vincennes Saint-Denis participated.
Thanks to the Lidar, 135 km2, or 70 times the study area studied so far, could be explored. First surprise: the density of human occupation in this region, much higher than we imagined until now (more than 62 000 structures identified including 12 000 for the Naachtun area). And among the other discoveries are the inter-connectivity, unsuspected on this scale, of Mayan cities between them via the construction of long roads that cross areas of hills and wetlands, the diversity of agrarian and hydraulic developments or the use of elaborate defensive systems. With the density of the occupation, it is the landscaping that surprise the most since, to take only the example of Naachtun, no less than 18 000 agricultural terraces, 5 400 drainage and irrigation channels in connection with agricultural micro-plots and 70 large reservoirs were identified. These results reveal an intensive and large-scale exploitation of environmental resources as well as risk management by the Mayan populations of the so-called classical period (150 to 950 AD).
Canuto M. A., Estrada-Belli F., Garrison T. G., Houston S. D., Acuña M. J., Ková? M., Marken D., Nondédéo P., Auld-Thomas L., Castanet C., Chatelain D., Chiriboga C. R., Drápela T., Lieskovský T., Tokovinine A., Velasquez A., . Fernández-Díaz J. C. and Shrestha R. 2018, Ancient Lowland Maya Complexity as Revealed by Airborne Laser Scanning of Northern Guatemala, in Science.
Geomorphological analyses have revealed the most ancient infrastructures of water management, dated 8000 years ago, at the Georgian Neolithic site Gadachrili Gora (Caucasus). A water stream rerouting using canals induced an inundation of the Neolithic village. The hydraulic infrastructures were then abandoned. Isotopic analyses on seeds from the archaeological site were used to identify the use of the canals for irrigation.
The Gadachrili Gora site, its canals and stratigraphy of the water management structures (CAD and photos : Vincent Ollivier).
River management for water supply is generally considered to have started 5500 years BC in the Middle East, with the development of the first Neolithic societies. In the South Caucasus, proofs of surprisingly early water management were found. A multidisciplinary team associating a past vegetation team (UMR 7209 du Muséum d’Histoire Naturelle, Paris) and radiocarbon dating as well as stable isotopes specialists (LSCE UMR 8212, Université Versailles St Quentin) allowed to perform a detailed reconstruction of the landscape and societies evolution in this Caucasus region.
The most ancient example of abstract drawing, performed with ochre, has been discovered on a fragment of siliceous rock in archaeological layers dated 73 000 years before present, in the Blombos cave (South Africa). This fragment holds on one of its sides nine lines, willingly drawn with an ochre fine-point pencil. It precedes by at least 30 000 years the most ancient abstract drawings using the same technique known before. This discovery was published on September 12, 2018 in Nature by an international team involving tow French labs : Pacea(1) ans Traces(2).
What is a symbol ? difficult question when the most ancient graphic designs has to be analyzed. Recent archaeological discoveries in Africa, Europe and Asia indicate an early use of symbols.
In this new article, researchers describe the most ancient known ochre pencil drawing. It was identified on a small piece of siliceous rock when analyzing rock tools from the Blombos cave in South Africa.
An abstract drawing from the 73,000-year-old levels at Blombos Cave, South Africa. Christopher S. Henshilwood, Francesco D’Errico, Karen L. van Niekerk, Laure Dayet, Alain Queffelec & Luca Pollarolo. 12 septembre 2018, Nature. DOI : 10.1038/s41586-018-0514-3
(1) laboratoire Pacea (CNRS/Université de Bordeaux/Ministère de la Culture)
(2) laboratoire Traces (CNRS/Université Toulouse – Jean Jaurès/Ministère de la Culture)
IN fifteen years, nearly 13 000 research articles have been published in the main science conservation journals. Nevertheless, biodiversity remains endangers everywhere in the world. Two CNRS researchers examined this paradox by reviewing the abundant literature on the subject. According to them, a major obstacle is the constant search for arbitrations more favorable to human activities than protection of nature. This study was published on September 10, 2018 in Trends in Ecology and Evolution.
The main threats to biodiversity have been known for about 40 years and are (i) the too strong use of resources (ii) species habitat fragmentation (iii) the introduction of invasive species and (iv) chain extinctions resulting from the three first factors. Today’s climate change further imbalance natural environments.
According to the researchers, proposals of durable solutions are not lacking. The major issue is rather the demand for arbitrations always more favorable to human activities than protecting the environment, in spite of scientific recommendations which are already shy.
An international team(1) has reconstructed a paleoprecipitation map which occurred in the tropical Andes 15 500 years ago, allowing to understand atmospheric processes which produced abrupt changes in the water cycle in tropical South America.
In the Southern part of the tropical Andes, today’s climate is extremely dry in the largest salted desert of the world: the Salar Uyuni. However, 15 500 years ago, this region was covered by the huge Tauca lake, with a size comparable to the Michigan lake.
In this study, researchers from CRPG and their colleagues used the glacial deposits on the Altiplano, together with a new methodology. A lake and a glacier have different sensitivities to precipitations and temperatures because more energy is needed to evaporate a lake than to melt a glacier. By reconstructing the simultaneous extents of Tauca lake and neighbouring glaciers, they quantified the temperature and precipitation conditions prevailing 15 500 years ago. They produced the first regional map of paleoprecipitations at the Altiplano scale.
(1) Centre de recherches pétrographiques et géochimiques (CRPG, CNRS / Université de Lorraine), Institut des géosciences de l’environnement (IGE/OSUG, CNRS / IRD / UGA / Grenoble INP), Laboratoire de géographie physique : environnements quaternaires et actuels (LGP, CNRS / Université Panthéon-Sorbonne / Université Paris-Est Créteil Val-de-Marne / INRAP), Centre européen de recherche et d’enseignement en géosciences de l’environnement (CEREGE/PYTHÉAS, CNRS / Aix-Marseille Université / IRD / Collège de France / INRA), Oslo University and Université Libre de Bruxelles