Palaeo-environmental evolution of the Kathari-Lichines marine bay (Kition, Larnaca, Chypre)

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History and influence of the Danube delta lobes on the evolution of the ancient harbour of Orgame (Dobrogea, Romania)

On the coast of Northern Dobrogea, south of the Danube delta, the Greek settlement of Orgame was founded in the mid 7th c. BC, probably by Milesian colonists. The ancient city was located on the Cape Dolojman which today overlooks a large lagoon complex. We undertook a chronostratigraphic study to:(i) understand coastal changes around Cape Dolojman since ca. 5000 years BP in connection with the construction of the Danube delta lobes, and (ii) identify potential sediment impacts related to human occupation of the site. Three cores were extracted from the lagoon area. Sedimentological and biological analyses were undertaken to reconstruct the evolution of the coastal palaeoenvironments. The results show a closure of the marine bay around 3500 cal. BP and its transformation into a lagoon environment. The first major environmental change was due to the construction of the lobe St. George I and the formation of the barrier Lupilor. Around 2000 cal. BP, the formation of an intra-lagoonal lobe, the Dunavatz, led to the gradual transformation of the lagoon into a fluvial-dominated system. Paradoxically, lagoon waters today still wash the ancient Greek harbour environment, which has not been totally infilled by alluvial sediments. To understand this paradox, in a context of coastal progradation, we compared and contrasted the geomorphological data with the nearby city of Istros/Histria, which was already landlocked at this time. The location of these two Greek colonies relative to the coastal sediment cell and barriers partly explains their contrasting palaeoenvironmental evolution. Until 2650 cal. BP, the increase in charcoal and organic matter in sedimentary archives is interpreted as an anthropogenic signal for a more extensive use of the vegetation cover following the foundation of the city of Orgame (e.g. for domestic use and funeral rites)

Agathe, an ephemeral island of the Languedoc coast? (Agde Hérault, France)

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Natural Constraints and potentials of some ancient harbours in the Mediterranean and Black Sea (Frejus, Ampurias, Kition, Istanbul, Orgame)

Il y a 7000 ans BP, la stabilisation du niveau marin a entraîné la formation de deltas. Ces zones deltaïques abritent des milieux aux degrés de protection différents favorables à une activité maritime. Cependant, ces espaces sont soumis à des contraintes naturelles : à l'échelle de la longue durée, l'alluvionnement des deltas entraîne la mobilité des littoraux et le colmatage des milieux portuaires ; à l'échelle de l'événement, les tempêtes, les tsunamis et la mobilité crustale entraînent la destruction, la submersion ou le soulèvement des zones portuaires. Ce travail porte sur l'étude des contraintes et des potentialités environnementales de cinq ports antiques répartis dans le monde Méditerranéen en marge de deltas. L'objectif est d'estimer le poids de ces contraintes sur les sociétés via une approche statistique. Pour quatre des sites d'études, l'alluvionnement est le forçage majeur. A Kition et Orgame, l'impact de l'alluvionnement est indirect. La fermeture des baies marines par l'édification de cordons littoraux crée des environnements lagunaires propices à l'installation de zones portuaires. En revanche, Fréjus et Ampurias sont soumis à un alluvionnement direct qui a rapidement colmaté les bassins. A partir de l'époque romaine et avec l'invention de la pouzzolane, des zones portuaires sont installées en milieu littoral ouvert, comme à Istanbul. Dans un contexte tectoniquement actif, les tsunamis constituent la contrainte majeure opérant sur le port byzantin de Théodose à Istanbul. Un dépôt grossier et chaotique, contenant du matériel marin et archéologique remanié, compose une partie de la séquence stratigraphique de colmatage du bassin et témoigne de ce forçage.The stabilization of sea level at 7000 years ago led to the formation of deltaic areas. These areas constituted sheltered environments particularly conducive to maritime activity. However, these areas were also subject to natural constraints for human occupation: at long timescales, high sediment supply to deltaic areas led to significative coastal changes and the infilling of harbour areas; at shorter timescales, high-energy events and crustal mobility led to the destruction, submersion and/or uplift of harbour areas. This work focuses on the study of environmental constraints and potentialities governing five ancient harbours, located on deltaic margins in the Mediterranean. The study aims to semi-qualitatively measure of the weight of these constraints on harbour cities, using statistical approach. High sediment supply is the major natural forcing. At Orgame and Kition, the closure of marine bays by coastal barriers led to the formation of lagoon environments conducive to the installation of harbour areas. Frejus and Ampurias were subject to direct siltation which quickly infilled the harbour basin. The invention of the pozzolan in Roman times means that harbours could be constructed in coastal areas open to the sea and away from river mouths, such as Istanbul harbour. In a tectonically active context, tsunamis are the major constraint acting in the Byzantine harbour of Theodosius in Istanbul. There, the stratigraphic sequence contains a coarse and chaotic deposit composed of reworked marine and archaeological material which demonstrates the societal impacts of such a natural and destructive forcing agent

Major storm events in the NW Mediterranean during the late Holocene : a new high-resolution multi-proxy lagoonal sedimentary record

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Géoarchéologie du port grec d’Empuriès : un port ouvert ou fermé ?

La cité antique d’Empuriès, située sur la marge sud de la plaine deltaïque des fleuves Fluvia et Muga, dans le golfe de Rosas (Catalogne), a fait l’objet de nombreuses fouilles archéologiques depuis plus d’un siècle. Trois villes antiques ont été découvertes ainsi que plusieurs zones portuaires dont l’une d’elles auraient servi aux colons grecs. Une campagne de carottages a été organisée afin de tester la localisation du port grec d’Empuriès, de comprendre l’évolution de la plaine deltaïque et son incidence sur le colmatage du port. Nous présentons ici les résultats concernant le « port grec ». L’analyse sédimentologique d’une carotte a permis de caractériser l’environnement du bassin qui s’apparentait à un milieu côtier plutôt battu. Ces données sédimentologiques ont ensuite été comparées à des données géoélectriques. Les résultats obtenus soulignent trois problèmes majeurs concernant la fonctionnalité du port : l’accessibilité délicate, le mode battu de son environnement ainsi que la faiblesse de sa hauteur d’eau. On peut donc émettre de sérieuses réserves quand à l’utilisation du « port grec » comme bassin protégé. Il s’agissait beaucoup plus d’un port ouvert sous la forme d’une plage de poche.The ancient city of Empuriès, located on the distal margin of the rivers Fluvia and Muga in the Gulf of Rosas (Catalunya), has undergone many archaeological excavations. Three Greco-Roman urban sites and a harbour area have been excavated. In December 2007, a coring campaign was organized to (i) precisely locate the “Greek Harbour”, and (ii) understand the Holocene evolution of the deltaic plain and its influence on the infilling of Empuriès’ Greek harbour. In this paper, we present results concerning the Greek harbour. Sedimentological analyzes of a core taken inside the speculated Greek harbour have allowed us to characterize its environmental evolution. We show that it constituted an exposed shoreline. These results are discussed within the context of geoelectric data. The results underline three problems concerning the functionality of the harbour basin : (i) difficult access ; (ii) an exposed environment ; and (iii) a shallow draught depth. This calls into question the idea of a protected Greek harbour. Instead, we suggest that Empuriès’ Greek harbour comprised an exposed pocket beach

Late Glacial to Holocene geomorphic and sedimentary evolution in the lower valley of the Hérault River, Northwestern Mediterranean

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Palaeogeography of Agathé, Languedoc coast

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