F. Eynaud

• PhD, HDR
• Maître de conférences at University of Bordeaux

Species assemblage composition of marine microfossils offers the possibility to investigate ecological and climatological change on time scales inaccessible using conventional observations. Planktonic foraminifera - calcareous zooplankton - have an excellent fossil record and are used extensively in palaeoecology and palaeoceanography. During the L...

Les archives sédimentaires holocènes, prélevées en contexte de plateforme, offrent une vision pluri-séculaire permettant de reconstruire l’impact des variations climatiques sur les environnements de la marge métropolitaine atlantique en s’éloignant de la période Anthropocène. C’est particulièrement le cas du dernier millénaire avec la succession de...

Marine Isotope Stage (MIS) 4 (ca. 71–57 ka; within the Middle Weichselian Substage) is considered a significant Pleistocene glaciation, but it remains poorly constrained in comparison to that of the Late Weichselian Last Glacial Maximum (LGM; ca. 29–19 ka, during MIS 2), or even the Late Saalian MIS 6 (ca. 190–130 ka). Most MIS 4 glacial landforms...

We combine consistently dated benthic carbon isotopic records distributed over the entire Atlantic Ocean with numerical simulations performed by a glacial configuration of the Norwegian Earth System Model with active ocean biogeochemistry in order to interpret the observed Cibicidesδ13C changes at the stadial–interstadial transition corresponding t...

We combine consistently dated benthic carbon isotopic records distributed over the entire Atlantic Ocean with numerical simulations performed by a glacial configuration of the Norwegian Earth System Model with active ocean biogeochemistry, in order to interpret the observed Cibicides δ13C changes at the stadial-interstadial transition corresponding...

A multiproxy sedimentological study was conducted on five sediment cores retrieved between 67 and 79°N in the Greenland/Iceland/Norwegian seas in order to infer a common chronostratigraphic model for the selected cores. This model is based on the use of a series of geochemical, physical and micropaleontological proxies which are routinely measured...

Reconstructions of ocean primary productivity (PP) help to explain past and present biogeochemical cycles and climate changes in the oceans. We document PP variations over the last 50 kyr in a currently oligotrophic subtropical region, the Gulf of Cadiz. Data combine refined results from previous investigations on dinocyst assemblages, alkenones, a...

The physical, sedimentological, mineralogical and elemental geochemical properties of sediment cores AMD1803-02BC and 01PC from the Cape Norton Shaw Inlet were investigated to reconstruct glacial sediment discharges from southeastern Manson Icefield and document the impact of ice–ocean interactions on the sediment dynamics and opening of the North...

Marine microcharcoal records provide invaluable information to understand changes in biomass burning and its drivers over multiple glacial and interglacial cycles and to evaluate fire models under warmer climates than today. However, quantitative reconstructions of burnt area, fire intensity and frequency from these records need calibration studies...

The main drivers of Europe's climate during the Holocene result from the coupling and interplay of external and internal radiative processes with the shifting patterns of many dynamic components (e.g. glaciers, ocean currents, wind fields, vegetation cover). Those driving forces were expressed across a range of geographical scales, from local to gl...

Since its existence, paleoceanography has relied on fossilized populations of planktonic foraminifera. Except for some extreme environments, this calcareous protist group composes most of the silty-to-sandy fraction of the marine sediments, i.e., the foraminiferal oozes, and its extraction is probably the simplest among the currently existing set o...

The northern Bay of Biscay has previously proven its great potential for recording the ‘Fleuve Manche’ paleoriver (i.e., the largest Pleistocene river in Europe) fluvio-glacial activity. In this study, new dinoflagellate cyst (dinocyst) analyses have been carried out at sub-centennial resolution in core MD13–3438 to reconstruct the deglacial histor...

The Gironde estuary in SW France is the largest in Western Europe and has attracted human populations since prehistoric times. From the 1970s to the 1990s, intense archaeological research was undertaken on the long and highly dynamic coastline just south of the estuary mouth. In recent years, the combined action of increased coastal erosion and hum...

The northern Bay of Biscay has proven, in previous studies, its great potential for recording fluvio-glacial activity thanks to its proximity to the mouth of the 'Fleuve Manche' paleoriver, the largest Pleistocene river in Europe. In the present work, new dinoflagellate cyst (dinocyst) analyses have been carried out at multidecadal resolution in co...

Résumé. L’étude de la production totale de coquilles typiques de l’association à Pupilla muscorum dans deux sites d’Europe occidentale (Nantois en Bretagne et Villiers-Adam dans le bassin de Paris) a permis de montrer l’existence de quatre brefs épisodes de réchauffement et d’augmentation de l’humidité pendant le Saalien supérieur. La comparaison a...

We discuss paleoenvironments of north-western France over the last 7 kyrs in terms of: i) long-term changes (relative sea-level rise and boreal summer insolation), ii) rapid climate changes (millennial-scale Bond events and multi-decadal regimes of the North Atlantic Oscillation: NAO) and iii) growing human impacts in watersheds. Our study focuses...

Coccolithophores are globally important marine calcifying phytoplankton. They contribute to the organic carbon pump through the primary production and the ballast of organic matter, and to the carbonate pump through the production of calcium carbonate. Here we compiled all available scanning electron microscopy (SEM) coccolithophore abundance obser...

Organic-walled resting cysts of planktonic dinoflagellates occur commonly in modern marine sediment where they represent, with rare exceptions, the only geologically preservable part of the life cycle. Although many species do not produce fossilizable resting cysts, upper Quaternary sediments contain a diverse cyst record that is used frequently fo...

We present a new version of the standardized Northern Hemisphere “modern” dinoflagellate cyst (“dinocyst”) database, which includes abundances of 71 taxa at 1968 sites across the Northern Hemisphere, cross-referenced with 17 environmental parameters extracted mostly from the 2013 World Ocean Atlas. Several taxa with tropical to warm temperate affin...

Sediment cores from the Mediterranean Sea have evidenced several periods of Sapropel deposition, which can be explained by events of anoxic bottom conditions. An explanation for such events calls for a very stratified sea, possibly related with freshwater input through increased precipitations and runoff discharges. It has been suggested that such...

On the seashore, archaeologi’cal remains appear well preserved and sometimes immediatly visible during erosion periods. But the constraints are accumulating at all levels : limited intervention time, water, movement of tides, rapid change due to erosion, access conditions to excavations, difficulty encountered in implementation of heavy infrastruct...

Rapid changes in ocean circulation and climate have been observed in marine-sediment and ice cores over the last glacial period and deglaciation, highlighting the non-linear character of the climate system and underlining the possibility of rapid climate shifts in response to anthropogenic greenhouse gas forcing. To date, these rapid changes in cli...

A coastal geoarchaeology analysis of the Aquitaine palaeoenvironments

Producing independent and accurate chronologies for marine sediments is a prerequisite to understand the sequence of millennial‐scale events and reveal potential temporal offsets between marine and continental records, or between different marine records, possibly from different regions. The last 40 ky is a generally well‐constrained period since r...

In the North Médoc (Gironde department), between the communes of Soulac-sur-Mer and Montalivet-les-Bains, the sandy shoreline has been exposed to a very strong erosion. Dealing with a rich archaeological, historical and environmental heritage, an interdisciplinary team has been constituted, consisting of archaeologists, geomorphologists and biologi...

Variations in North Atlantic Ocean mid-depth circulation during the Holocene are poorly understood. It is believed that they had a significant influence on the properties of water entering the Nordic Sea by redistributing heat and freshwater, potentially affecting deep-water formation and climate. To improve our knowledge of the NE Atlantic mid-dep...

The adaptation of territorial systems to the ongoing climate change is an issue which implies to test past populations abilities to cope, to “bounce back” or to adapt during similar past environmental changes. The chronostratigraphical and archaeological results, obtained in the frame of the LITAQ project, make it possible to better understand chan...

Located at the mouth of the Gironde estuary (southwestern Atlantic coast of France), the Amélie beach recorded a huge coastal erosion during the recent stormy events, especially in the winter 2013-2014. The dune scarping and the sediment depletion on the beach uncovered a set of estuarine and aeolian sediment deposits containing numerous archaeolog...

Abstract QUATINT_2019_45 Onshore and offshore evidences for four abrupt “warming” episodes during MIS 6 at the westernmost tip of continental Europe: did they control the migrations of Neanderthals? Full Length Article The total shell production typical of the Pupilla association in the onshore site of Nantois (Brittany, France) evidenced for the f...

In marine sediments of late Cenozoic age, Spiniferites is a very common genus of dinoflagellate cysts (dinocysts). Despite some taxonomical ambiguities due to large range of morphological variations within given species and convergent morphologies between different species, the establishment of an operational taxonomy permitted to develop a standar...

A mid- to late-Holocene paleohydrological reconstruction from the northeast Atlantic is proposed through the study of a high-resolution sedimentary record from the northern continental shelf of the Bay of Biscay (BoB). Three foraminiferal species dominate the assemblages with Rosalina globularis showing an overall decrease in absolute and relative...

La version numérique est disponible ici : https://www.terres-du-passe.com/page-123-reunion-des-sciences-de-la-terre-2018.htm Le détroit de Fram est la seule connexion directe actuelle entre les eaux chaudes et salées de l’Atlantique Nord et les eaux froides et plus douces de l’Arctique. Le courant atlantique remonte par l’est, le long de la marge...

Lille. France

Lille, France

A proper understanding of local palaeoenvironmental histories is an iterative process. Previously settled interpretations suddenly demand a reconsideration triggered by findings from sites not accessible before. The coastline of the Médoc area in South-West France faced considerable recent erosion, providing new valuable insights into the history o...

The past two million years of eastern African climate variability is currently poorly constrained, despite interest in understanding its assumed role in early human evolution. Rare palaeoclimate records from northeastern Africa suggest progressively drier conditions or a stable hydroclimate. By contrast, records from Lake Malawi in tropical southea...

The dynamics of Northern Hemisphere ice sheets during Late Quaternary glacials have yet been dominantly examined from a Lauren tide Ice Sheet perspective, which helped shaping the idea of moisture‐starved glacials and small‐scale ice volume variability. However, the waxing and waning of the European Ice Sheet (EIS) casts doubt on this perception. U...

This paper illustrates a new compilation of sea-surface hydrographic data (SST mainly) derived from multiproxy reconstructions on high time-resolution (decadal to centennial) marine archives. This compilation is focussed on the boreal Atlantic and gathers Holocene sedimentological records (defining the HAMOC database) which were retrieved in the vi...

Neogloboquadrina pachyderma represents a key planktonic foraminifera species in the boreal Atlantic and has been extensively used as a paleoceanographic tool in polar to subpolar environments. The species shows an intraspecific morphological variability, displaying at least 5 different morphotypes previously documented from northern and southern oc...

Reconstructing the colonization and demographic dynamics that gave rise to extant forests is essential to forecasts of forest responses to environmental changes. Classical approaches to map how population of trees changed through space and time largely rely on pollen distribution patterns, with only a limited number of studies exploiting DNA molecu...

Dansgaard–Oeschger and Heinrich events constitute ones of the most enigmatic features of the last glacial period. Many studies have focused on their characteristic millennial climatic variability, testing atmospheric/cryospheric/oceanic couplings, but major uncertainties and discrepancies still remain. Anew scenario, robustly supported by an approa...

For the first time a very high resolution palynological study (mean resolution of 1 to 5 years) was carried out over the last 150 years in a French estuarine environment (Bay of Brest; NW France), allowing direct comparison between the evolution of landscapes, surface water, and human practices on Bay of Brest watersheds, through continental (espec...

Toulouse, France

Toulouse, France

The last glacial millennial Heinrich and Dansgaard–Oeschger events have been the subject of many studies in recent decades. However, significant uncertainties remain, notably regarding associated oceanic mechanisms. Here we investigate the evolution of hydrographical conditions in the 3–41 ka cal BP interval of core MD99-2285 located in the souther...

Dansgaard–Oeschger oscillations constitute one of the most enigmatic features of the last glacial cycle. Their cold atmospheric phases have been commonly associated with cold sea-surface temperatures and expansion of sea ice in the North Atlantic and adjacent seas. Here, based on dinocyst analyses from the 48–30 ka interval of four sediment cores f...

This paper documents the evolution over the last 10 kyr of one of the key parameters of climate: sea-surface temperatures (SSTs) in the North Atlantic. We focus on the southern Bay of Biscay, a highly sensitive oceanographic area regarding the dynamics of the North Atlantic subpolar and subtropical gyres (SPG and STG respectively). This site furthe...

Dansgaard-Oeschger oscillations constitute one of the most enigmatic features of the last glacial cycle. Their cold atmospheric phases have been commonly associated with cold sea-surface temperatures and 15 expansion of sea ice in the North Atlantic and adjacent seas. Here, based on dinocyst analyses from the 48-30 ka BP interval of four sediment c...

Paleoceanographical changes during the Holocene were reconstructed from the study of core MD95-2002 situated in the northern Bay of Biscay, which is marked by the direct influence of the northeastern return branch of the North Atlantic Drift. Palynological data, sea-surface condition estimates based on dinocyst assemblages and stable isotope measur...

The last glacial millennial climatic events (i.e. Dansgaard-Oeschger and Heinrich events) constitute outstanding case studies of coupled atmosphere-ocean-cryosphere interactions. Here, we investigate the evolution of sea-surface and subsurface conditions, in terms of temperature, salinity and sea ice cover, at very high-resolution (mean resolution...

New dinoflagellate cyst (dinocyst) analyses were carried out at high resolution in core MD99-2339, retrieved from a contouritic field in the central part of the Gulf of Cadiz, for the Marine Isotope Stage (MIS) 3 interval, allowing for discussion of palaeohydrological changes over the last 50 ky in the subtropical NE Atlantic Ocean. Some index dino...

This paper documents the last 10 ka evolution of one of the key parameters of climate: sea-surface temperatures (SST) in the subpolar North Atlantic. We focus on the southern Bay of Biscay, a highly sensitive oceanographic area because of its strategic and nodal position regarding the dynamics of the North Atlantic subpolar and subtropical gyres. T...

New dinoflagellate cyst (dinocyst) analyses were carried out at high-resolution in core MD99-2339, retrieved from a contouritic field in the central part of the Gulf of Cadiz, for the Marine Isotope Stage (MIS) 3 interval, allowing to discuss paleohydrological changes over the last 50 ky in the subtropical NE Atlantic Ocean. Some index dinocyst tax...

The present study aims at reconstructing past climate changes and their environmental impacts on plant ecosystems during the last 6000 years in the Middle Atlas, Morocco. Mean January temperature (Tjan), annual precipitation (Pann), winter (Pw) and summer (Ps) precipitation, and a seasonal index (SI) have all been quantified from a fossil pollen re...

Bordeaux, France.

Bordeaux, France.

FAST-LITAQ aims to better define the geomorphological, climatic and environmental factors that govern the deposition and fossilization of the Late Quaternary sediments outcropping along the Medoc Peninsula.

IODP 339 Site U1385 ("Shackleton site", e.g. Hodell et al., 2013a), from the SW Iberianmargin, offers the opportunity to study marine microfossil population dynamics bycomparing several past interglacials and to test natural shifts of species that occurred acrossthese warm periods, in a subtropical context. Here, more specifically, we present resul...

The Sahara experienced several humid episodes during the late Quaternary, associated with the development of vast fluvial networks and enhanced freshwater delivery to the surrounding ocean margins. In particular, marine sediment records off Western Sahara indicate deposition of river-borne material at those times, implying sustained fluvial dischar...

The last glacial period was punctuated by abrupt climatic events with extrema known as Heinrich and Dansgaard–Oeschger events. These millennial events have been the subject of many paleoreconstructions and model experiments in the past decades, but yet the hydrological processes involved remain elusive. In the present work, high-resolution analyses...

Les études antérieures portant sur les systèmes turbiditiques du golfe de Gascogne (systèmes Celtique, Armoricain et du Cap-Ferret) n’ont jamais permis d’atteindre leurs parties terminales (Bourillet et al., 2006) et ce uniquement en raison de l’absence de levés dans ces zones. Afin de connaitre leurs extensions réelles nous avons compilé des donné...

Pontarlier, France.

The Holocene climate is known to be rather stable although with few abrupt changes that lasted few decades. The present study is related the climate changes and their environmental impacts during the last 6000 years from a fossil record collected in the Middle Atlas, Morocco. Reconstruction of three climate variables (January temperature (Tjan), an...

The last glacial period was punctuated by abrupt climatic events with extrema known as Heinrich Events and Dansgaard–Oeschger cycles. These millennial events have been the subject of many paleoreconstructions and model experiments in the past decades, but yet the hydrological processes involved remain elusive. In the present work, high resolution a...

Brest, France.

The core MD03-2693 (43 degrees 39.258N; 01 degrees 39.805W; 431m water depth) was collected on an abandoned meander of the Capbreton Canyon (SE Bay of Biscay), filled over the last millennia by very high sedimentation rates (mean sedimentation rate of 1.2cm/yr) linked to its specific environmental location and fine-grained clayed sediment decantati...

Full text, figures and supplement available in open access at: http://www.clim-past.net/10/2115/2014/ Glacial climate was characterised by two types of abrupt events. Greenland ice cores record Dansgaard–Oeschger events, marked by abrupt warming in-between cold, stadial phases. Six of these stadials appear related to major Heinrich events (HEs),...