Pierre Giresse

• PhD
• Professor Emeritus at University of Perpignan

The Appendix lists the 160 archaeological radiocarbon dates from sites within and around the Sangha River Interval

There is a broad agreement that towards the end of the Holocene in Central Africa there was a drier “Late Holocene Forest Crisis” (LHFC) that impacted the Central African rainforest between c. 2500-2000 cal yr BP. The Sangha River Interval or SRI is such a hypothesized rainforest region. This climate-driven LHFC has been thought to have benefited t...

Clay mineral authigenesis at continental margins plays an important role in global marine element cycles. However, despite being increasingly used as tracers for both modern and past oceanographic conditions, the behavior of the rare earth elements (REEs) and their isotopes during marine clay authigenesis still remains poorly known. In this study,...

The Great Amazon Reef System is a living biogenic mesophotic reef ecosystem that has been recently described along the shelf break of Brazil. An oceanographic cruise was carried out in 2019 along the outer edge of the French Guiana Shelf. A side-scan sonar survey was conducted to locate reef outcrops and allowed twelve in situ 80- to 120-m depth di...

The Gulf of Lions shelf (southern part of the French Mediterranean coast) displays several occurrences of beachrocks, thus offering an exceptional opportunity to determine the stages of the last marine transgression. These beachrocks crop out especially on the outer shelf and near the modern shoreline. In addition, several other exposures are locat...

The vast tropical rainforests of West and Central Africa were impacted by marked climatic deterioration, which mainly developed between 2500 and 2000 cal yr BP. However, the incidence of human intervention in these rainforests appears all the more speculative, although this was the period when the first stages of Bantu migration occurred towards th...

The Great Amazon Reef System is a living biogenic mesophotic reef ecosystem that has been recently described along the shelf break of Brazil. An exploration mission was carried out in 2019 along the outer edge of the French Guiana Shelf. A side-scan sonar survey was conducted to locate reef outcrops and allowed twelve in situ 80 to 120 m depth dive...

The Great Amazon Reef System is a living biogenic mesophotic reef ecosystem that has been recently described along the shelf break of Brazil. An exploration mission was carried out in 2019 along the outer edge of the French Guiana Shelf. A side-scan sonar survey was conducted to locate reef outcrops and allowed twelve in situ 80 to 120 m depth dive...

A core from a peat bog in the “Niayes” region, northwest of Senegal, provides a valuable insight into the evolution of the landscape and fire regime related to the West African Monsoon rainfall and to human impact over the Holocene. The high-resolution multiproxy approach based on stable carbon isotopic composition (δ¹³C), Rock-Eval® thermal analys...

For a long time, particular attention was paid to glauconitization in the surficial sediments lying on the outer continental shelves of present oceans. Subsequently, the processes observed and analyzed may have served as models for studies of glauconite in Cenozoic or even Mesozoic shelf deposits. Access to the sedimentary domains of deep oceans, p...

an Open Access Journal by MDPI Formation and Evolution of Glauconite. New Scale Approach Guest Editor: Prof. Dr. Pierre Giresse CEFREM, UMR 5110 CNRS, Université de Perpignan Via Domitia, 66860 Perpignan, France giresse@univ-perp.fr Deadline for manuscript submissions: 16 June 2022 Message from the Guest Editor For a long period of time, particular...

Contourite sediment accumulations at continental margins are related to strong bottom water circulation, where intense winnowing can result in neoformation of authigenic grains of glauconite at the seafloor. In this study, we investigated whether such glauconite grains could faithfully record ambient bottom-water neodymium (Nd) isotopic composition...

Off French Guiana and Surinam, NADW and AABW oceanic currents contour the Demerara marginal plateau, which promotes the formation of contourites. We have studied these contourites thanks to a new compilation of high-resolution sub-bottom profiles calibrated by sedimentary cores. The echo-facies and isopach maps we constructed highlight a sedimentar...

Published by Science Advances, 13 May 2021 - Response to the published paper “Seidensticker (D.), Hubau (W.), Verschuren (D.), Fortes-Lima (C.), de Maret (P.), Schlebusch (C.M.) & Bostoen (K.), 2021, Population collapse in Congo rainforest from 400 CE urges reassessment of the Bantu Expansion, Science Advances, Published online: 12 February 2021, V...

Le linteau en marbre blanc de l’église abbatiale de Saint-Genis-des-Fontaines, dans le sud du Roussillon, est reconnu comme la plus ancienne sculpture romane datée de l’Occident (1020-1021). Il présente de fortes analogies stylistiques avec le linteau et la table d’autel de l’église voisine de Saint-André-de-Soréde. Ce sont ces trois pièces sculpté...

Thirty-eight samples were taken from the banks of the Sanaga River and its main tributaries draining different plant ecosystems, but also from rivers in the coastal basins of Cameroon. This study aims to characterize the origins of pollen and the dominant mode of transport of pollen inputs to the continental shelf. The classical method of pollen sp...

La montagne peut paraître à première vue étrangère aux circulations des hommes comme des ressources. Pourtant, l’espace montagnard, lieu de départ ou de refuge depuis toujours, se caractérise par des circulations permanentes qui, en dépit des difficultés imposées par des contraintes naturelles qui peuvent être fortes, se caractérisent par leur ampl...

Paleoclimatic changes are the most probable causes of the rainforest crises 2,600 y ago in Central Africa.

Plusieurs églises romanes de l'Est des Pyrénées (Albères, Aspre, Cerdagne) édifiées sur des terrains schisteux paléozoïques renferment des pierres de construction rouge foncé à structure bréchique et à ciment ferro-siliceux qui n'avaient jamais été signalées à ce jour. Ces pierres furent spécialement choisies à des fins ornementales (encadrements d...

Several Romanic churches of eastern Pyrenees (Albères, Aspre, Cerdagne) built on Paleozoic schistose bed-rocks show dark red building stones with breccia structure and ferro-siliceous cement that were never reported so far. Considering the abundance of schistose sandstones in the landscape around, this uncommon dark red stone with light gray clasts...

A wide range of lithological materials was used for the numerous architectural monuments build in the eastern Pyrenean domain during the brief Majorquine dynasty and that are inlarge part slightly well preserved nowadays. The lithology and the mineralogy of materials implemented in monuments were defined and compared with the various facies observe...

During the warmer Holocene Period, two major climatic crises affected the Central African rainforests. The first crisis, around 4000 cal yr BP, caused the contraction of the forest in favor of savanna expansion at its northern and southern periphery. The second crisis, around 2500 cal yr BP, resulted in major perturbation at the forest core, leadin...

This region, comprised between the Kouilou estuary and Pointe-Noire, is characterised by a very specific morphological setting. On the continental side, the coastal sector is dominated by cliffs of sand over 100 m high, referred to as the Série des Cirques, whereas, on the ocean side, very active erosion is presently taking place which has resulted...

Sedimentological and geochemical analyses and 14C dating were performed for a sedimentary core sample from the Lopé 2 marsh in the northern zone of Gabon's Lopé National Park. The results produced a division of the core sample into three main units. The basal part of the core sample was dated to 2,320 years cal BP. At this time, the Lopé 2 marsh wa...

Le plateau de Demerara forme un promontoire bathymétrique le long de la Guyane française et du Surinam. Il est décrit comme un plateau marginal issu d’une structuration en mode transformant (Mercier de Lépinay, 2016). Ce relief est composé d’un plateau continental suivi d’un second plateau plus profond, compris entre 200 et 3200 m, dont la partie d...

L'analyse des données de sismique réflexion haute résolution et leur comparaison à la lithologie des carottes des sédiments fini-quaternaires de la partie septentrionale du plateau continental camerounais permettent d'évaluer la qualité de la réponse sismique et d'envisager l'apport de cet outil dans la caractérisation des sédiments et de la dynami...

Clay fraction contents distribution in the Senegal River estuary after the building of the anti-salt Diama dam has shown that upstream sediments are very muddy. Clay fraction content is as high as 60 % of sediments in the middle of the channel with a pronounced downstream decreasing trend on the banks comparing to the contents in the middle of the...

The Demerara Plateau, belonging to the passive transform margin of French Guiana, was investigated during the IGUANES cruise in 2013. The objectives of the cruise were to explore the poorly-known surficial sedimentary column overlying thick mass transport deposits as well as to understand the factors controlling recent sedimentation. The presence o...

During the late Pliocene, the Roussillon plain was the site of repeated accumulations of fine-grained silty deposits, locally intercalated with sandy-gravelly flood deposits. Such sediment-accumulation processes implied that, around 4 Ma ago, the manifestations of structural collapse of the plain had virtually ceased, and that subsidence had become...

The IGUANES cruise took place in May 2013 on the R/V L’Atalante along the Demerara passive transform margin off French Guiana and Surinam. Seismic, multibeam and chirp acquisitions were made. Piston cores were collected for pore geochemistry and sedimentology. A mooring was deployed on the sea-bottom for 10 months (temperature, salinity, turbidity...

A Contourite Depositional System (CDS) has been described at the Demerara Plateau (DP) based on seismic investigations, but little is known about the mechanisms of associated sediment deposition and its interaction with past deep ocean circulation patterns (e.g. bottom current velocity) and bottom morphology related to ancient event of slope instab...

Le Plateau de Demerara a été le sujet d’une campagne océanographique (IGUANES) en Mai 2013. L’un des objectifs de cette mission et l’objectif de ce travail est de comprendre les différents processus sédimentaire qui affectent cette zone particulière et leurs possibles interactions entre eux. Pour cela, de nombreuses données géophysiques (bathymétri...

Sur le plateau de Demerara, un CDS (Contourite Depositional System) a été décrit grâce à la présence de différentes structures sur le fond marin (« comet tail », « longitudinal waves », contourite drifts, contourite moats) mais aussi grâce à la présence de séquence de contourites décrites au sein des carottes sédimentaires. En parallèle des variati...

A dense grid of high- and very high resolution seismic data, together with piston cores and borehole data providing time constraints, enables us to reconstruct the history of the Bourcart canyon head in the western Mediterranean Sea during the last glacial/interglacial cycle. The canyon fill is composed of confined channel-levee systems fed by a se...

The Pleistocene alluvial conglomerates of the Verdouble River valley, close to the famous Palaeolithic site of Tautavel, were the object of lithologie determinations including microtextural analysis intended to define their provenance, their sedimentary facies and their calcite cement. Previous age assignments by other authors envisage that these c...

In order to better constrain the relationship between tectonics and sedimentation of the Eastern Sardinian Margin, from the Messinian to the present day (METYSS project), a lithostratigraphic study was carried out on the Late Neogene deposits along the Cedrino Valley (eastern Sardinia). The late Neogene evolution is documented from sedimentological...

In order to better constrain the relationship between tectonics and sedimentation of the Eastern Sardinian Margin, from the Messinian to the present day (METYSS project), a lithostratigraphic study was carried out on the Late Neogene deposits along the Cedrino Valley (eastern Sardinia). The late Neogene evolution is documented from sedimentological...

Le projet METYSS-METYSAR est un chantier terre-mer bénéficiant du soutien programmatique « Actions Marges » qui a notamment pour objectif de contraindre les relations entre tectonique, sédimentation, et évolution géodynamique de la Marge Est- Sarde (Gaullier et al., 2014). L’ouverture arrière-arc de la Mer Tyrrhénienne, entre la Sardaigne et le dom...

La campagne océanographique IGUANES a eu lieu en mai 2013 sur le Plateau de Demerara dans le cadre d’un partenariat entre le CEFREM et l’IFREMER. L’un des objectifs de cette mission était d’appréhender les processus sédimentaires affectant la marge guyanaise peu connus jusqu’à maintenant. Ce plateau forme un promontoire de 380 km de long, 220 km de...

We report preliminary data for a multidisciplinary investigation of the eastern Demerara Plateau conducted in 2013 during the IGUANES cruise (seismic and bathymetric data, sediment cores, and mooring). Our first observations show the presence of a vast field of longitudinal bed forms and comet marks between 2000 and 2800 m water depth, with a NW-SE...

The narrow shelf and upper slope immediately above the Gonone canyon head off NE Sardinia represent areas of very low sedimentation rates. Along the sides of the canyon head (1,600 m water depth), the sediment deposits are homogeneous but show alternating light-grey intervals rich in carbonate and dark-grey ones rich in organic matter, possibly rel...

The recent paper in this journal by Thié blemont et al. (2013) (TH) discusses mainly about the coarse-grained stone lines (S L) in central Africa, particularly the most recent one, and also the fine-grained Cover Horizon (C H) above the S L. This study supplies various interesting precisions on the implementation of S L and C H. So ''geochronologic...

Lake level changes of Barombi Mbo (Cameroon) during the Late Quaternary : compared catchment and crater lake records.

In recent years, Nguène Lake and Kamalété Lake (Gabon, West Central Africa) have been studied repeatedly, providing comprehensive reconstructions of environmental changes over the last millennia. Both lakes are in different geomorphological and environmental settings. They are therefore excellent sites to test new methodological approaches. Indeed,...

Effects of density, shape, hydrodynamic conditions of deposition, samples from Catalonia (Spain), southern Cotentin (France), and Gabon

Bayon et al. (Reports, 9 March 2012, p. 1219) claim that the “rainforest crisis” in Central Africa centered around 2500 years before the present “was not triggered by natural climatic factors” and that it was caused by widespread deforestation resulting from the arrival of the Bantu colonists. However, there is a consensus among palaeoecologists th...

After the discoveries of pre-Acheulian and Acheulian industry accumulations in the depression of the external ring of Guelb er Richât (Mauritanian Adrar) by Théodore Monod, it was proceeded to an exhaustive study of surrounding Quaternary sediments. Slopes in the south of the cliffs of Ordovician quartzite sandstones are covered with chaos of block...

This paper presents the results from field observations, geochemical and mineralogical analyses, radiocarbon dating and magnetic susceptibility of the Holocene sediments of two crater lakes, Mbalang and Tizong, located within the woody savanna of the Adamawa Plateau (Cameroon). In the Mbalang core (M4) with an age of 7318 cal. BP at the base, the f...

Past limnological conditions of Lake Mbalang (7°19′ N, 13°44′ E, altitude: 1130 m) and vegetation type were reconstructed from diatoms and sedimentary stable carbon isotope records (δ¹³C) since 7200 cal yr BP. The data showed that before 3600 cal yr BP, the water column was dominantly stable except around 5000–5300 cal yr BP where diatom...

Deux carottes KS02 et KS07 ont été prélevées à des profondeurs assez proches (1602 m et 1648 m) sur les versants du canyon d'Orosei, le long de la marge est-sarde, lors de la campagne "METYSS 2" (avril 2010, N/O " Téthys II "). Elles présentent des logs lithologiques assez comparables. Sur la base de 8 premières datations AMS du 14C, on constate de...

Cette étude se situe dans la perspective de l'analyse de l'évolution post-messinienne de la marge ouest-tyrrhénienne (programme Metyss). Les pentes accidentées des reliefs granitiques au dessus de la vallée du Cedrino sont couvertes de l'amont vers l'aval par des blocs chaotiques, des accumulations de poudingues et brèches polygéniques ou monogéniq...

Le projet terre-mer METYSS a pour objectif de comprendre les effets immédiats et différés de la Crise de Salinité Messinienne (CSM) ainsi que les relations tectonique et sédimentation sur la marge est-sarde. Cette marge résulte de l'ouverture de la Mer Tyrrhénienne à partir du Tortonien et jusqu'au Messinien (c. 9 à 5 Ma). Des bassins profonds exis...

The equatorial west African continental margin comprises depocenters located offshore major river mouth (e.g. Ogooué, Congo, Cunene.. .). Accumulation rate in these deep-sea-fans steadily increases as from Early Oligocene, and reaches a maximum in the Plio-Quaternary time. Such increase in terrigenous sedimentation indicates an increase of continen...

Past limnological conditions of Lake Mbalang (7 • 19 N, 13 • 44 E, altitude: 1130 m) and vegetation type were reconstructed from diatoms and sedimentary stable carbon isotope records (δ 13 C) since 7200 cal yr BP. The data showed that before 3600 cal yr BP, the water column was dominantly stable except around 5000–5300 cal yr BP where diatoms evide...

Seismic data and sediment cores collected offshore from the Sanaga River and Nyong River mouths were used to analyse a loose mantle of yellow to reddish sandy gravel with a range of fluvial and deltaic characteristics cropping out in the middle part (25–65 m water depth) of the continental shelf of Cameroon. Contrary to most of the Atlantic shelves...