Dans le cadre du PCR, une mission de carottage s’est déroulée le 17 août 2020 dans la plaine alluviale située en contrebas du fort de Girolata. L’équipe était constituée de Matthieu Ghilardi ...(chercheur CNRS au Cerege) et de Jean-Baptiste Mary (doctorant de l’université Lumière Lyon 2 et rattaché au laboratoire Hisoma), assistés de Jean-François Luciani (Mairie d’Osani).Les objectifs de cette mission étaient, dans un premier temps, de pouvoir reconstituer la mobilité du trait de côte depuis l...
Soil formation in Mediterranean periglacial karst landscapes remains poorly understood as the interplay between local and allochthonous sources of parent materials, and mineral alteration and ...pedogenesis, as dominant post‐depositional processes, depends on a variety of climatic and environmental factors. Herein, we investigate the balance between erosion and aeolian dust accretion in the formation of an alpine soil profile in the periglacial zone of Mount Olympus in Greece. We applied a wide range of analytical methods to 23 samples, from a soil profile developed in a glaciokarstic plateau, from colluvial sediment horizons interbedded in postglacial scree slopes of different maturity and formation age and from modern Sahara dust samples deposited on the snowpack. Colluvial sediment horizons exhibit high concentrations of carbonate gravel and calcite‐rich sand and represent the local erosion products. The soil B horizon developed on the glaciokarstic plateau, contains high amounts of fine earth and is rich in quartz, mica, plagioclase, clays and Fe–Ti oxides. Based on physical and textural characteristics, the soil profile is partitioned in a surficial weathered Bw and an illuvial Bt horizon that overlies the local regolith composed of fragmented glacial till and slope wash deposits. Radiogenic isotope systematics, textural and mineralogical analysis show that the contribution of aeolian (Sahara and locally sourced) dust to the development of the soil B horizon ranges between 50% and 65%. Cryoturbation results in fine earth translocation from Bw to the Bt horizon, whereas weak pedogenetic modifications of detrital (aeolian and bedrock‐derived) minerals result in magnetic mineral weathering and secondary clay formation. Our findings reveal that aeolian dust accretion from Saharan and lcal sources is the dominant process in providing alpine soil parent material and that cryoturbation, weak pedogenesis and clay mineral alteration occur within the Mediterranean periglacial zone of Mount Olympus.
The evaluation of the alpine soil production along a short 2‐km erosional gradient in the periglacial zone of Mount Olympus, Greece, allowed us to demonstrate that despite significant textural and mineralogical differences between sandy horizons interbedded in postglacial scree slopes and developed soils formed in a glaciokarstic plateau filled with glacial till and slope wash sand and gravels, aeolian dust accretion outweighs local erosion in providing soil parent materials, which after their initial deposition are paedogenetically modified, and disturbed by cryoturbation, which may be the case for the majority of Mediterranean periglacial landscapes.
The town of Rue was one of the most important coastal harbours of Picardy, Northern France, from the beginning of the 12th century to the end of the 15th century CE. Document sources and ancient maps ...confirm the existence of this vibrant harbour. Until now, however, no palaeoenvironmental studies have attempted to reconstruct the configuration of the region's coastline during medieval times. Here we employ a geoarchaeological approach to reconstruct the Mid-to Late Holocene shoreline and landscape changes in the Rue area. Our approach includes a geophysical survey (Electric Resistivity Tomography method) and a series of eight sediment cores that reveal the region's chronostratigraphy. Document sources were also used to shed light on the landscape configuration during the Late Middle Ages (ca. 1300 CE). Our coring results, based on sedimentological analyses, are combined with 2D geophysical profiles down to 21.50 m. This reveals, firstly, that a calm marine environment prevailed at the beginning of the 4th millennium BCE, particularly in depressions bordered by Pleistocene coastal spits (foraines). Secondly, from ca. 3500 BCE to ca. 1000 BCE, coastal swamps predominated. Then, thirdly, at around 1000–1250 CE, an estuarine depositional environment prevailed, prior to a final period of land reclamation of the former Maye Estuary from the 13th century CE onwards. These results agree well with recent work on sea level changes along the Atlantic and English Channel coasts of France, where continuous post-glacial sea level rise has been observed. Our study also proposes a location of the medieval harbour of Rue to the west of the town at the upstream boundary of the upper part of the Maye Estuary, near ‘Le Moulin de Saint-Jean’, although archaeological evidence of the exact site of this tidal harbour is still lacking.
Relative sea level change occurred along the western coast of the Istrian peninsula in Croatia. Sediments from two cores located in the bay of Santa Marina and Soline Bay have been analyzed for ...microfaunal and sedimentological investigations. Chronostratigraphical evidence was obtained from
14C dating of lagoonal shells (gastropods). From the sedimentological and paleo-environmental analysis, 4300 years of continuous deposition in a shallow marine environment was determined. At around 550 cal BP, marine sedimentation changed to continental. Consequently, the initial sedimentation rate of 0.7 mm/y changed to 2.36 mm/y after 550 cal BP. Those upper deposits of continental origin are today partly submerged. The data were further compared with a geophysical model which allows the prediction of the local sea level curve. As the results from the cores are largely below the curve, tectonic subsidence of the area is confirmed. Radiocarbon analysis allowed the age of the shells to be related to the age of the submerged tidal notch that occurs almost continuously some hundreds of meters south-eastwards, from the Gulf of Trieste to the Dalmatian coast.
In this study, we present a new glacial chronology based on 20 in situ-produced 36Cl-based cosmic ray exposure datings from moraine boulders and bedrock from the Throne of Zeus (TZ) and Megala ...Kazania (MK) cirques on Mount Olympus. The 36Cl derived ages of glacial landforms range from 15.6 ± 2.0 to 0.64 ± 0.08 ka, spanning the Late-glacial and the Holocene. The Late-glacial, recorded in both cirques, is partitioned in three distinct phases (LG1-3): an initial phase of moraine stabilization at 15.5 ± 2.0 ka with subsequent deglaciation starting at ∼14 ka (LG1), followed by a shift to marginal conditions for glaciation at 13.5 ± 2.0 ka (LG2), sustained by large amounts of wind-blown snow, despite regional warming. Glacial conditions returned at 12.5 ± 1.5 ka (LG3) and were characterized by low air temperatures and glacier shrinking. The Holocene glacial phases (HOL1-3) are recorded only in the MK cirque, likely due to its topographic attributes. An early Holocene glacier stillstand (HOL1) at 9.6 ± 1.1 ka follows the regional temperatures recovery. No glacier activity is observed during the mid-Holocene. The Late Holocene glacier expansions, include a moraine stabilization phase (HOL2) at 2.5 ± 0.3 ka, during wet conditions and solar insolation minima, while (HOL3) corresponds to the early part of the Little Ice Age (0.64 ± 0.08ka). Our glacial chronology is coherent with glacial chronologies from several cirques along the northeast Mediterranean mountains and in pace with numerous proxies from terrestrial and marine systems from the north Aegean Sea.
•The first 15ka-long glacial chronology of the southern Balkans, based on 20 36Cl-based cosmic ray exposure datings from Mount Olympus, Greece.•Three Late-glacial (LG1:15.5-14.0 ka, LG2:13.5ka, LG3:12.5ka) and three Holocene (HOL1: 9.6ka, HOL2: 2.5ka, HOL3: 0.64ka) glacial phases.•HOL1-3 glacial phases occur only in the NW-oriented Megala Kazania cirque emphasizing the role of the local topography on Mediterranean glaciations.•Glacial variability and solar insolation exhibit an out-of-phase behavior during the Late-glacial, but are synchronized during the Holocene.•The new glacial record provides additional evidence for a seesaw Mediterraean climatic pattern during the Younger Dryas and the Little Ice Age.
This paper presents the results of a geoarchaeological study undertaken in Upper Egypt, in the western part of the Karnak Temples complex. The geoarchaeological approach helps to better understand ...the fluvial dynamics of the Nile in the proximity of the Pharaonic site during the late Holocene. Until recently, most researchers assumed that Karnak was built on a fluvial island and that a large basin connected to the Nile was built in front of the first pylon during the dynastic period. However, recent excavations conducted by the archaeologists of the Supreme Council of Egyptian Antiquities revealed a jetty or quay with probable direct access to the Nile. Therefore in order to reveal in more detail the landscape and waterscape changes in the most western part of Ancient Karnak, a palaeoenvironmental study was conducted. We studied several stratigraphic profiles, manual boreholes (maximum depth of 5.50 m) and percussion drillings (maximum depth of 25 m). Sedimentological and magnetic susceptibility analyses helped to characterize Nile River deposits and to identify the presence of aeolian deposits (associated with
wadi fan deposits) in the lower part of the drillings. Fluvial dynamics characterized by flood events, sandy accretions and thick Nile silts/clay deposits are presented and discussed here for later palaeoenvironmental reconstruction. Accurate leveling of the different profiles and boreholes, together with a topographic survey, allow us to recover long sedimentological sequences and to correlate the different sedimentary units. Finally, in order to obtain a chronostratigraphic sequence, radiocarbon dates were obtained from wood, charcoal and ash samples (analyses undertaken at the laboratory of radiocarbon dating of Ifao, Cairo, Egypt). The presence of the Nile River in front of the first pylon in Karnak is attested from the end of the Second Intermediate Period (SIP, ca 1600 BC) until the end of Roman Times (ca. 350 AD), which both correspond to two main phases of Nile River floods.
► First Radiocarbon dating have been performed in Upper Egypt in order to obtain a chronostratigraphy of the Nile River sediment accumulation. ► Circa 4000 years ago, the first temples in Karnak have been installed on a sandy levee system called a Gezirah. ► Nile River was flooding in the most western part of the Karnak Temples complex from the 16th Century BC until the 4th Century AD. ► Two phases of high flows of the Nile have been recorded during the New Kingdom (15th Century BC) and Roman times (from the 2nd to the 4th Century AD).
A new dataset of 16 C-14 radiocarbon dates better constrains Relative Sea Level (RSL) changes in Corsica Island since the late Neolithic (similar to 3.6 ka BCE). Conflicting Holocene RSL histories ...between the northern and southern portions of Corsica coast are presently available in literature. Here we provide new RSL data obtained by sediment coring and beachrock analysis performed along the eastern coast of the island. These data, coupled with previously available ones, were compared with the predicted RSL variations modelled by means of the sea-level equation solver SELEN. Data from different coastal sectors of Corsica indicate a coherent pattern of RSL since the late Neolithic when the RSL was placed similar to 3.8 m below the present mean sea level. Then sea-level rose at rate of similar to 2 mm a(-1) in the Chalcolithic period (similar to 3.5 and similar to 2.3 ka BCE) followed by a significant deceleration with rates <= 0.4 mm(-1) from the early Bronze Age to present time (last 4.0 ka). The total RSL variation since similar to 0.5 BCE does not exceed similar to-0.9m. Our data are in good agreement with previous sea-level estimates made using fixed biological indicators collected in NW Corsica and derived from geo-archaeological investigations in continental France. Conversely, beachrock samples from the Bonifacio strait (southern Corsica) seem to significantly underestimate the RSL position especially between similar to 3.5 and similar to 0.5 ka BCE. Such discrepancy might reflect radiocarbon calibration issues rather than sea-level variation. These results suggest that further multiproxy investigations are fundamental to better assess the regional sea-level evolution of this archaeologically important sector of the Mediterranean. (C) 2016 Elsevier Ltd. All rights reserved.
As part of the Changing the Face of the Mediterranean Project, we consider how human pressure and concomitant erosion has affected a range of Mediterranean landscapes between the Neolithic and, in ...some cases, the post-medieval period. Part of this assessment comprises an investigation of relationships among palaeodemographic data, evidence for vegetation change and some consideration of rapid climate change events. The erosion data include recent or hitherto unpublished work from the authors. Where possible, we consider summed probabilities of 14C dates as well as the first published synthesis of all known optically stimulated luminescence dated sequences. The results suggest that while there were some periods when erosion took place contemporaneously across a number of regions, possibly induced by climate changes, more often than not, we see a complex and heterogeneous interplay of demographic and environmental changes that result in a mixed pattern of erosional activity across the Mediterranean.
Comparison of historical leveling and of recent GPS data reveal that the wider Thessaloniki plain (North Greece), a 2500 years old delta, has subsided in the last 50+ years up to 3.5 m. These results ...are consistent with independent estimates of subsidence in the suburbs of Thessaloniki and testify to a plain-wide effect. Rather localized increased subsidence resulting from hydrocompaction due to intense pumping is superimposed on the plain-wide subsidence. The latter seems to mimic the long-term tendency of landscape change, as the correlation between recent surface deformation and deformation derived from boreholes reveals. Furthermore, differential subsidence seems to control the flow of rivers and the overall morphology of the delta. The significance and necessity of geoid corrections in the comparison of historical and GPS data is also indicated.
En 2019, les activités du PCR se sont poursuivies avec la réalisation d’opérations de prélèvement par carottage dans la lagune de Biguglia, ainsi qu’avec de nouvelles analyses de laboratoire pour les ...autres sites étudiés (Crovani, Calenzana et San Ciprianu, Lecci) (fig. 1). Fig. 1 – Cartographie des activités 2019 DAO : M. Ghilardi (CNRS). Un carottage de 4,20 m de longueur a été réalisé en octobre (équipe : Matthieu Ghilardi, CNRS et François Warichet, Université de Liège, Belgique) en coll...
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