One of the prominent features of northeast Mediterranean (NEM) Holocene climate are recurrent phases of cold and aridity; their impacts on the hydrological cycle remain at large unknown, as few ...existing paleohydrological records are either restricted to lake-level fluctuations or focus near the ‘8.2 kyr BP’ event. Here, we present the detrital record of Aliakmon River in Lake Loudias between 9500 and 3000 cal. BP. Magnetic susceptibility (MS) exhibits high correlation with mean grain size (r = 0.7) of silt-sized fractions and is used as a proxy of the distal clastic input of Aliakmon River, whereas organic matter (OM), carbonate content (CaCO3), water content (WC), and clay concentrations decipher sedimentological and biological processes in Lake Loudias. Periods of high hydrological activity were interrupted by short intervals of low river discharge at c. 9400, 8600, 8200, 7500, 7000, 6200, 5300, and 4500 cal. BP and during a multi-century event centered at 3500 cal. BP, in agreement with marine and terrestrial paleoclimatic reconstructions from NEM. With exception of the wet period between c. 8.6 and 7.9 cal. BP, periods of increased hydrological activity are synchronous to contraction of Pinus forests and increased sea surface temperatures and silt transport in the Aegean Sea. The long-term (~580 years) variability of MS is in-phase with southeast Europe pollen-inferred annual temperature variations and with North Atlantic Ice Rafted Debris (IRD) events.
A recent suite of Relative Sea-Level (RSL) data for the past 12 ka BP has provided new insights into the sea-level histories of the western Mediterranean region. Our analysis of the ...chronostratigraphic context of sea-level indicators from Spain (Catalonia, the Balearic Islands and the Gulf of Valencia), France (Corsica Island) and Italy (Sardinia Island) has yielded 162 new sea-level index and limiting points. These data have considerably enhanced previous RSL compilations, in addition to improving the quality of spatio-temporal sea-level reconstructions and our capacity to estimate isostatic-related vertical motions in the western Mediterranean basin. The glacial and hydro-isostatic adjustment (GIA) pattern elucidated by the new database shows discrepancy with respect to those predicted by the available GIA models. In particular, the new results underscore a non-coherent isostatic response of the central portion of the western Mediterranean, with the Balearic Islands manifesting significant departures from the sea-level histories of Corsica, Sardinia and, more generally, along most of the western Mediterranean coast. Our results are a crucial contribution to defining both the pattern and the magnitude of the isostatic signal along the western Mediterranean coast. In fact, vertical isostatic motions represent a key to better assess any possible post-industrial acceleration in sea-level rise and to define future scenarios of coastal inundation in the context of global change.
•Recent studies in the western Mediterranean yielded 163 new sea-level datapoints.•We reconstruct the sea-level evolution along the Spanish coasts, Corsica and Sardinia.•We outlined a non-coherent isostatic response of the bulk of the basin.•The Balearic Islands manifested a significant departure from the GIA models.•We better defined the maximal magnitude of the isostatic signal in the Mediterranean.
Parmi les dix mille îles et îlots de Méditerranée, moins de trois cents seraient habités et seulement deux cents mesureraient plus de 5 km2. Ces îles sont des entités géologiques et géographiques ...complexes où coexistent des formations de roches très anciennes et d'autres créées très récemment (îles volcaniques). A la fois ouvertes sur l'horizon et les côtes continentales voisines, elles restent, paradoxalement, relativement fermées de par leur isolement, créant ainsi des spécificités quant à leur biodiversité et leur colonisation par les sociétés humaines. Les îles de Méditerranée forment ainsi un objet d'étude privilégié pour la géoarchéologie. Celte dernière emprunte les concepts, les méthodes et les techniques de disciplines relevant des sciences humaines et environnementales (l'archéologie, l'épigraphie, la philologie, la géographie. la paléoécologie, la paléontologie...). Cet ouvrage établit un premier état des connaissances dans le domaine de la géoarchéologie des îles de Méditerranée. L'éclatement géographique de ces dernières, ainsi qu'une histoire de l'occupation propre à chacune, démontrent toute la difficulté de globaliser ces espaces géographiques, progressivement transformés en territoires sous l'action répétée des sociétés humaines. Des spécialistes dressent ici les relations complexes entre les dynamiques et les processus paysagers et les logiques d'occupation humaine depuis la fin du Pléistocène. Le présent ouvrage recueille vingt-quatre contributions regroupées dans cinq parties intitulées « Anthropisation et mutations paysagères à la transition Paléolithique/Néolithique » ; « Mobilité et reconstitution des anciens niveaux marins depuis la fin de la dernière grande glaciation quaternaire » ; « Adaptation aux mutations paysagères à l'échelle intra-site : la nécessaire prise en compte des paramètres environnementaux » ; « Deltas, lagunes et marais : des interfaces propices à l'implantation des sociétés humaines » et « Matières premières ; exploitation et interactions ». Cet ouvrage s'adresse principalement à des spécialistes de géographie, d'archéologie et de paléoécologie mais aussi à un public plus large : étudiants des niveaux L-M-D, enseignants et simples néophytes souhaitant s'initier aux concepts, méthodes et techniques de la géoarchéologie.
This study investigates the possibility of Holocene glaciation on Mount Olympus (Greece) with a respective local temperature–precipitation equilibrium line altitude (TP-ELA) at c. 2200 m a.s.l., ...based on geomorphologic and paleoclimatic evidence. At present, the local TP-ELA is situated above the mountain’s summit (c. 2918 m a.s.l.), but permanent snowfields and ice bodies survive within Megala Kazania cirque between c. 2400 and c. 2300 m a.s.l., because of the cirque’s maritime setting that results from its close proximity (c. 18 km) to the Aegean Sea and of the local topographical controls. The snow and ice bodies occupied a considerably larger area and attained a stabilization phase between AD 1960 and 1980, also manifested from aerial photographs, a period characterized by increased winter precipitation (Pw) with subsequent TP-ELA depression to c. 2410 m a.s.l. Mid- to late-20th-century Pw and TP-ELA variations exhibit negative correlations with the winter North Atlantic Oscillation index (NAOw) at annual and multidecadal (30 years) timescales. Late Holocene (AD 1680–1860) reconstructed summer mean temperatures were lower by Ts < 1.1°C in relation to the reference period between AD 1960 and 1980 and were also superimposed to negative NAOw phases, thus bracketing this time interval as a favorable one to glacial formation and/or advance. Millennial-scale annual precipitation reconstructions at the hypothesized TP-ELA (c. 2200 m a.s.l.) point the period between 8 and 4 kyr BP as another glacier-friendly candidate. The mid-Holocene rather simplistic sequence of potential glacial advance phase was disturbed by short-lived cold climatic deteriorations, well-documented over the northern Aegean region that may partly explain the multicrested shape of the highest (c. 2200 m a.s.l.) morainic complex of Megala Kazania cirque.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The study was conducted in the southern part of the lower Strymon valley, in northern Greece, and revealed up to 25 m of fluvio-lacustrine sediments deposited over the last seven millennia. This ...sedimentary record represents a significant opportunity for high-resolution palaeoenvironmental studies of the period from 6 to 3 ka cal BP linked to land use and climate change. The results of geophysical investigations, multi-proxy sedimentological (grain size, magnetic susceptibility, loss-on-ignition), pollen and NPP analyses, based on high-precision radiocarbon dating enabled reconstruction of past landscapes as well as a comprehensive discussion of anthropogenic responses and their impact on the vegetation cover, especially during periods with well-known Holocene Rapid Climate Change events (5.6, 4.2 and 3.2 ka cal BP).
During the 7–5.7 ka cal BP corresponding to the Late and Final Neolithic, wet conditions created an extended lake surrounded by the densely wooded Strymon watershed, followed by a shift to a shallower lake environment that lasted until ca. 4.5 ka cal BP. The continuous presence of anthropogenic taxa suggests the persistence of human activities even in the absence of formally recognized sites, suggesting the relocation of settlements. The first signs of human disturbance of the landscape at regional scale occurred toward 5.2 ka cal BP (onset of the Early Bronze Age). The so-called « 4.2 ka BP event », which coincided with the end of the Early Bronze Age and the transition to the Middle Bronze Age, is divided into three distinct periods (4.35–4.1, 4.1–3.95 and 3.95–3.75 ka cal BP). The first corresponds to gradual aridification before a period with severe dry conditions that marks a tipping point toward wetland contraction. From this period on, diversification, and multiplication of anthropogenic species including Olea, Juglans and Castanea reflect a global trend toward cultural landscapes. The later periods are characterized by dramatic climatic change around 3.2–3 ka cal BP, at the end of Late Bronze Age, and increasing impacts of agro-pastoral activities and forest clearing starting at the beginning of Antiquity, around 2.8 ka cal BP (Thracian period). After the 4.2 ka cal BP event and we suggest that climatic adversity may have acted as a stimulus to innovation and relocation rather than retarding societal development in the region. To conclude, environmental factors in the lower Strymon valley were not sufficient on their own to trigger a social crisis similar to that mentioned in the Middle East.
•Continuous chronostratigraphic sequence of 24.5 m covering the last seven millennia.•Attested anthropogenic impact from the Late Neolithic.•A dry period is recorded at 4.2 ka cal BP.•Continuous agricultural practices only evidenced since 4 ka cal BP.•Human resilience indicates complex interplay between ecological and cultural factors.
A multi-proxy investigation of sediment cores has enabled us to reconstruct the coastal environmental evolution of East-Central Corsica (the sites of Saint Florent, Piantarella-Bonifacio and ...Palo-Solenzara) for the last 8000 years. The analytical methods comprise pollen (five original pollen diagrams), weight loss-on-ignition measurements, laser granulometry, and ostracod identification. In addition, 26 radiocarbon dates are used to provide a robust chronostratigraphy for the sedimentary sequences. The assessment of coastal landscape dynamics enables us to define the major morphological changes and to evaluate the complex interplay between climatic forcing and anthropogenic activity on the vegetation history of Corsica, within an archaeological context, since the early Neolithic period (∼7.4 cal kyr BP). The major findings are that the first farmers reached Corsica by sea, and they encountered a coastal environment mainly composed of freshwater ponds located close to the shoreline. This specific paleoenvironmental feature offered a favourable location for agriculture and for the development of permanent settlements where a subsistence economy was developed. Since the Middle Holocene, postglacial sea-level rise has caused major changes in local coastal environments, often characterized by salt intrusion into freshwater bodies. At the transition between the Mid and Late Holocene (∼4.0 cal kyr BP), an increase in both salinity and aridity caused substantial landscape changes, mainly characterized by a further expansion of saline marshland, mainly occupied by Chenopodiaceae. The results also provide new insights into the role of Erica in the original Holocene vegetation of Corsica. Our data clearly indicate that an Erica arborea - Quercus ilex forest transition occurred before 6.3 cal kyr BP, significantly earlier than previously proposed. Finally, the earliest evidence of cereal cultivation is at ∼7350 cal kyr BP, and in addition we are better able to constrain the role of humans in the landscape dynamics of Corsica since the early Neolithic.
•Erica arborea - Quercus ilex forest transition occurred before 6.3 cal kyr BP.•Earliest evidence of cereal cultivation in Corsica (∼7350 cal kyr BP).•Expansion of saline marshland in the Mid to Late Holocene transition.
The present paper provides new insights into the climatic and anthropic factors that influenced a 6000-year coastal evolution in northwestern Corsica, the third largest island of the western ...Mediterranean. Pollen, microcharcoal, sedimentary and geochemical analyses were carried out on a core drilled in the Crovani coastal wetland to reconstruct the regional drivers of landscape change. We show that anthropogenic and climate-induced fires favoured the development of Mediterranean maquis, dominated by Erica and Quercus ilex, from ca. 6000 to 3350 cal. BP. A change in arboreal vegetation triggered a short but intense sediment input in the Crovani pond between ca. 3350 and 3200 cal. BP. This is consistent with a coeval process of runoff recorded in several coastal sites of western Corsica and related to an arid climate change occurred in many sites of the western Mediterranean around 3200 years ago. We provide evidence of agriculture during the Late Neolithic from ca. 3900 BC, which is much earlier than any archaeological evidence previously available in this area of Corsica, followed by a progressive decline of arable farming practices. Human impact has been responsible for a degradation of the maquis only from approximately 3000 cal. BP, and it intensified in Roman times, when the area experienced the first phase of galena exploitation from the Argentella mines. Over the last 500 years, the present work evidences a major development of Castanea related to cultivation during the Genoese administration of Corsica. Our findings suggest that solar activity and the North Atlantic Oscillation had an influence on centennial-scale forest cover variations during the last 6000 years.
•A new palynological, sedimentological and geochemical study is presented from a coastal wetland of Corsica.•The high-resolution 6000-year pollen record shows an unprecedented long persistence of Erica and Quercus ilex maquis.•Human activities developed especially during the Late and Final Neolithic and the last 1000 years.•Evidence of agriculture predates any Neolithic archaeological findings in this region.•The 4.2 ka event, Homeric Minimum, and Little Ice Age are not associated with forest declines.
We produced a new suite of sea-level data which allowed assessing the Holocene evolution of the Bonifacio Strait, a key coastal sector of the Mediterranean Sea which experienced significant ...morphological changes since the Last Glacial Maximum. Squeezed between Corsica and Sardinia islands, this strait connects the two major basins of the western Mediterranean. Due to its peculiar geographic and morphological setting, the Bonifacio Strait is affected by extreme meteomarine conditions characterized by severe winds, waves, and currents.
The millennial sea-level changes were reconstructed through multiproxy investigations made of sediment coring and underwater beachrock sampling carried out on both sides of the strait. These data provided fresh insights into the timing of the progressive opening of the Bonifacio Strait which followed the Last Glacial Maximum when Corsica and Sardinia were connected forming the largest Mediterranean island. Major palaeogeographic changes occurred before ~7 ka BP. Since that period, the significant decrease of the northern ice-sheet melting triggered a significant sea-level stabilization which induced only minor modifications in the palaeogeography of the strait. In the late Holocene, the isostatic-related subsidence became the dominant factor controlling the sea-level changes which rose with rates ≤0.35 mm a−1 in the last four millennia.
Our data have also an important archaeological implication because they indicate that the Bonifacio Strait has not represented a significant geographical barrier along the early Neolithic migration path which connected mainland Italy to northern Corsica and finally to Sardinia. This further confirms the ability of early Neolithic communities to navigate not also across large sea stretches but also maritime areas characterized by extremely complex meteomarine conditions.
•An analysis of the postglacial evolution the Bonifacio strait•The Bonifacio strait is a key coastal area of western Mediterranean•New insights into the timing of progressive opening of the strait were provided•Major paleogeographic changes occurred before ~7 ka BP•Sea-level rose with rates ≤0.35 mm a−1 in the last four millennia•The strait did not represent a geographical barrier for early Neolithic migrations
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