Reconstructing the Holocene coastal development of the Laurentine Shore

The Laurentine Shore is the Imperial Roman palaeo-shoreline preserved up to 1km inland of the southern, distal edge of the Tiber Delta coastline of Lazio, western Central Italy. The progradation of the delta is recorded on the site as a series of shore-parallel relict dune ridges. High-status villas developed along the roman period coastline, with a service village (Vicus Augustanus), and other infrastructure such as roads, aqueduct, piscinae and several baths (thermae), these structures have been examined using a multi-scale geoarchaeological approach. A sea level reconstruction based on multi-proxy palaeo-environmental analysis of a silt/peat sedimentary transition from the base of a Roman piscina suggests that the sea level at ca. 2400 ± 40 BP was around 1.25 ± 0.2 m below modern sea level. This analysis provides further context for assessing the development of the site during the late Holocene in relation to the progradation of the Tiber delta and for the important Imperial Roman period occupation of the Laurentine Shore and other important sites such as Portus and Ostia Antica in the central part of the Tiber delta. At several key periods in the late Holocene, the palaeo-shoreline has been reconstructed using a geochronological framework of optical luminescence dates and geomorphological survey of the Tiber Delta dune ridge record. In particular, during the Imperial Roman period, ca. 2000 BP) it has been shown that the Laurentine Shore was settled during a period of significant Tiber delta shoreline progradation. Two-major building phases at the Vicus Augustanus occur within this progradation phase. By the abandonment of the site in the 5th century AD, the shoreline was around 70 m seaward of the shoreline during the 1st building phase of the Vicus. This rate of shoreline change could be noticeable by the population over decadal timescales and may have driven the alteration of coastal building and property plots during the 500 year lifetime of the settlement. A combined methodology incorporating sedimentology, geochemistry and petrological analysis of diagenetically altered sediments found that early vadose diagenesis may have a deleterious effect upon luminescence dating dosimetry, inducing age underestimation, especially of reddened dune sands. Petrological analysis has also shown that a lack of anomalous fading in luminescence behaviour observed in K-feldspars may be due to a lack of complex microstructure in the mineral grains driven by the metamorphic, Alpine origin of these minerals. An assessment of the geoarchaeological approach used in this thesis shows that a scale-driven context provides a useful structure for examining the various processes and factors affecting the geomorphological and sedimentological records improving confidence in the examination of the archaeological record.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Reconstructing the fluvial history of the Lilas River (Eu-boea Island, Central West Aegean Sea) from the Mycenaean times to the Ottoman period

Funding: Aix-Marseille University.This paper aims to reconstruct the alluvial activity for the Lilas river, the second-largest catchment of Euboea Island (Central Western Aegean Sea), for approximately the last three and a half millennia. The middle reaches (Gides basin) exhibit several historical alluvial terraces that were first recognised in the 1980s but have remained poorly studied, resulting in uncertain chronological control of palaeofluvial activity. In order to reconstruct the past fluvial dynamics of the Lilas river, a ca. 2.5 m thick stratigraphic profile has been investigated for granulometry and magnetic parameters. Absolute dating of the sediments was possible by applying Optically Stimulated Luminescence (OSL). The results reveal: (i) two coarse-grained aggradational episodes dated from the Mycenaean/Early Iron Age and the Roman periods, respectively, (ii) a phase of rapid fine-grained vertical accretion corresponding to the Late Byzantine to early Venetian periods, (iii) potential evidence for final alluvial deposition from the Little Ice Age/Ottoman period, and (iv) two major incision episodes inferred from Ancient Greek times and most of the Byzantine period. Based on the published core material, the paper also evaluates the direct impacts of the Late Holocene alluviation recorded mid-stream on the fluvial system situated downstream in the deltaic area. Sediment sourcing is attempted based on the magnetic properties of the catchment lithology and of alluvium collected upstream along the main stream bed. Finally, the present paper discusses the possible links between Late Holocene hydroclimatic oscillations and the aggradational/incision phases revealed in the Gides basin. Correlations are attempted with regional palaeoclimate records obtained for the Aegean. In addition to climatic variability, anthropogenic factors are considered: specific land use for agricultural purposes, in particular during the Mycenaean period, the Roman and the Late Byzantine/Early Venetian periods, might have enhanced sediment deposition. Archaeological information and pollen records were also evaluated to reconstruct regional land-use patterns and possible impacts on soil accumulation over the last 3.5 millennia.Publisher PDFPeer reviewe

Rapidly changing worlds. Finding the earliest human occupations on Scotland's north-west coastline

During the Late Glacial and Early Holocene periods Scotland was a mountainous north-westerly peninsula of Europe. Recently, a small number of sites across Scotland have demonstrated a human presence here from several continental Late Glacial and Early Holocene cultural periods including the late Hamburgian Havelte, Federmesser, Ahrensburgian and Fosna-Hensbacka which date to approximately 14,500–10,500 BP. But the discovery of sites, even on current emerged coastlines is haphazard. Artefacts occasionally appear by chance from underwater contexts discovered by accident, while a small number of known sites are situated in intertidal zones. Broad sea level reconstructions using high resolution survey methods, particularly offshore morphological landform studies and recovery and identification of microfossils from cored soil samples, are building an image of relative sea levels (RSL) throughout the Pleistocene and Holocene in Scotland and demonstrate the very significant role of isostatic recovery as well as eustatic sea level rise in the RSL during the Late Pleistocene and early to mid-Holocene. Yet very little is known on a smaller scale and few regional sea-level curves exist. On the north-west coast, the isostatic effects can be highly localised and variable and sometimes several different sea levels of different ages can be found interspersed with no easy way to reconstruct their relative ages. This paper outlines the current evidence for early prehistoric intertidal archaeology in western Scotland and discusses a research strategy to build on this. Based on current evidence and with such a fragmented coastline, meaning that the RSL data that exists cannot be easily extrapolated, the best way forwards at present is to pinpoint areas with potential for submerged remains based on archaeological evidence for distribution patterns of onshore lithic scatters and also evidence of rolling that might suggest artefact movement. In the future, when more RSL and geomorphological data become available and more sites are found that permit development of a local predictive model, offshore landscapes could be selected for targeted underwater survey

Scotland's intertidal prehistory: Lub Dubh Aird, a raw material and knapping site in Upper Loch Torridon

Sea-level rise and coastal change have impacted on the visibility of early to mid-Holocene sites worldwide. Due to the combination of eustatic and isostatic effects, modern coastal landscapes rarely reflect those occupied and exploited by prehistoric people. This suggests that intertidal and marine archaeology is set to become increasingly important in future studies of the coastal populations of prehistoric Britain. Though Scotland’s west coast is renowned for its abundance of evidence for the Mesolithic, the potential for intertidal sites has barely been investigated. We report on a newly discovered raw material source and primary knapping location on the beach and across the intertidal zone at Lub Dubh Aird, Upper Loch Torridon. Our results suggest that a multi-disciplinary approach to investigation into early prehistoric human occupation of the west Scottish coastline – that incorporates survey of intertidal zones together with the upper beach and nearby areas – is essential to fully appreciate the range of sites present and to allow these to be integrated into a better understanding of coastal landscape use at this time

A multiscale geoarchaeological approach from the Laurentine shore (Castelporziano, Lazio, Italy)

The ability to investigate meaningful geoarchaeological questions is driven by appropriate scale-process focus fundamentally informing sampling strategies. This in turn, is driven by site-specific characteristics such as topography, sedimentology, geochemistry and climate. The Laurentine Shore is the Roman-period palaeo-shoreline preserved up to 1 km inland of the modern coastline of the Tiber Delta at the southern distal end. Mid- to late-Holocene progradation of the Tiber Delta linked to sediment supply in the context of changing relative sea level drives the macro-scale (103+) development of the region. Archaeological remains preserved within the Presidential Estate of Castelporziano must be interpreted within this macro-scale context. Using a multiscale, transect-based approach, SAAD-IRSL luminescence dating of relict foredune ridges has provided an age model constraining the development of the Tiber delta during the late Holocene. Both radiocarbon (Giraudi et al., 2009) and luminescence chronologies of dune ridge phases are in good agreement. Due to the protected status of the Castelporziano Estate the Holocene coastal dune topography is better preserved than at the central delta area and two additional phases of dune ridge formation are observed. Four macro-scale phases of delta progradation are recorded by the dune ridge record with increased mean rates of progradation observed during the Roman period and within the last 500 years. On the meso-scale (102) the high-status villas on the Laurentine Shore, and the Vicus Augustanus that serviced the villas are specifically located on the Roman-period shoreline. The timing of settlement (from around 2050 BP, i.e., 1st century BC) occurs during a pronounced Tiber delta progradation phase. Within this macro-scale context issues of sediment supply, frequency of Tiber flooding and the expression of shoreline advance at the Laurentine Shore have important meso-scale consequences for the development of the archaeological sites. It is likely that during the 2-phase development of the Vicus Augustanus that shoreline progradation was an observable phenomenon on decadal to multi-decadal timescales. Indeed the second, major seaward construction phase of the Vicus Augustanus likely occurred upon land that did not exist during the first phase, directly linked to delta progradation and the macro-scale processes acting upon the development of the site including anthropogenic activity in the Tiber catchment during the Roman period.La pertinence des questions géoarchéologiques est directement conditionnée par le choix d’une échelle de travail adaptée dans le but de proposer par la suite des stratégies d’échantillonnage appropriées et efficaces. Ces dernières sont localement influencées par les caractéristiques propres d’un site telles que sa topographie, la nature des sédiments sur lesquels il a été bâti, son environnement (paramètres géochimiques) et son climat. Le littoral laurentin correspond à l’ancienne ligne de rivage datée de l’époque romaine et qui est aujourd’hui localisé à 1 km du trait de côte actuel, dans la partie méridionale du delta du Tibre. La progradation de ce dernier, au cours de l’Holocène moyen et récent, est à mettre en liaison directe avec l’apport sédimentaire de son bassin versant dans un contexte de stabilisation du niveau relatif de la mer, cela permet notamment d’appréhender l’évolution morphologique de la région concernée (la superficie de la zone considérée de l’ordre de 103 km2). Des vestiges archéologiques particulièrement bien conservés dans la région de Castelporziano doivent être justement replacés dans un contexte morphologique régional pour pouvoir être interprétés sur le plan géoarchéologique. En privilégiant une échelle régionale d’étude et en se fondant sur l’établissement de transects, ainsi que sur la datation par Luminescence SAAD-IRSL de cordons dunaires fossiles, on parvient à fournir un modèle évolutif du delta du Tibre au cours de l’Holocène. Les datations obtenues permettent de reconstituer les différentes phases d’édification des cordons dunaires. En raison de la position d’abri de la région de Castelporziano, la topographie des cordons dunaires d’âge holocène y est mieux conservée que dans la partie centrale du delta, il est d’ailleurs possible d’y observer deux cordons supplémentaires. A une échelle régionale, quatre phases majeures de progradation deltaïque ont ainsi été identifiées avec une hausse particulièrement bien marquée du rythme d’avancée du trait de côte durant la période romaine et au cours des cinq cent dernières années. A une échelle moyenne de travail (superficie de la zone considérée de l’ordre de 102 km2), il est possible d’observer que les villas romaines et le Vicus Augustanus sont implantés sur le littoral laurentin. Cette période d’occupation (environ 2050 BP-1er siècle ap. J.-C.) correspond d’ailleurs à une avancée significative du delta du Tibre. La progradation du trait de côte a eu des conséquences directes sur le développement des sites archéologiques. C’est essentiellement pendant la seconde phase de l’expansion du Vicus Augustanus que la progradation est un phénomène observable à l’échelle décennale voire pluri décennale. En effet, l’expansion vers la mer du Vicus Augustanus est intervenue alors qu’aucun territoire n’existait pendant la première phase. Cela est à mettre en relation directe avec la progradation deltaïque et les processus morphologiques affectant le bassin versant du Tibre pendant la période romaine, incluant en particulier les activités d’origine anthropique

Reconstructing the fluvial history of the Lilas River (Eu-boea Island, Central West Aegean Sea) from the Mycenaean times to the Ottoman period

This paper aims to reconstruct the alluvial activity for the Lilas river, the second-largest catchment of Euboea Island (Central Western Aegean Sea), for approximately the last three and a half millennia. The middle reaches (Gides basin) exhibit several historical alluvial terraces that were first recognised in the 1980s but have remained poorly studied, resulting in uncertain chronological control of palaeofluvial activity. In order to reconstruct the past fluvial dynamics of the Lilas river, a ca. 2.5 m thick stratigraphic profile has been investigated for granulometry and magnetic parameters. Absolute dating of the sediments was possible by applying Optically Stimulated Luminescence (OSL). The results reveal: (i) two coarse-grained aggradational episodes dated from the Mycenaean/Early Iron Age and the Roman periods, respectively, (ii) a phase of rapid fine-grained vertical accretion corresponding to the Late Byzantine to early Venetian periods, (iii) potential evidence for final alluvial deposition from the Little Ice Age/Ottoman period, and (iv) two major incision episodes inferred from Ancient Greek times and most of the Byzantine period. Based on the published core material, the paper also evaluates the direct impacts of the Late Holocene alluviation recorded mid-stream on the fluvial system situated downstream in the deltaic area. Sediment sourcing is attempted based on the magnetic properties of the catchment lithology and of alluvium collected upstream along the main stream bed. Finally, the present paper discusses the possible links between Late Holocene hydroclimatic oscillations and the aggradational/incision phases revealed in the Gides basin. Correlations are attempted with regional palaeoclimate records obtained for the Aegean. In addition to climatic variability, anthropogenic factors are considered: specific land use for agricultural purposes, in particular during the Mycenaean period, the Roman and the Late Byzantine/Early Venetian periods, might have enhanced sediment deposition. Archaeological information and pollen records were also evaluated to reconstruct regional land-use patterns and possible impacts on soil accumulation over the last 3.5 millennia

Mid- to Late Holocene shoreline reconstruction and human occupation in Ancient Eretria (South Central Euboea, Greece)

International audienceFew studies have aimed to reconstruct landscape change in the area of Eretria (South Central Euboea, Greece) during the last 6000 years. The aim of this paper is to partially fill in this gap by examining the interaction between Mid- to Late Holocene shoreline evolution and human occupation, which is documented in the area from the Late Neolithic to the Late Roman period (with discontinuities). Evidence of shoreline displacements is derived from the study of five boreholes (maximum depth of 5.25 m below the surface) drilled in the lowlands of Eretria. Based on sedimentological analyses and micro/macrofaunal identifications, different facies have been identified in the cores and which reveal typical features of deltaic progradation with marine, lagoonal, fluvio-deltaic and fluvial environments. In addition, a chronostratigraphy has been obtained based on 20 AMS 14C radiocarbon dates performed on samples of plant remains and marine/lagoonal shells found in situ. The main sequences of landscape reconstruction in the plain of Eretria can be summarized as follows: a marine environment predominated from ca. 4000 to 3200 cal. BC and a gradual transition to shallow marine conditions is observed ca. 3200-3000 cal. BC due to the general context of deltaic progradation west of the ancient city. Subsequently, from ca. 3000 to 2000 cal. BC, a lagoon occupied the area in the vicinity of the Temple of Apollo and the settlement's development was restricted to several fluvio-deltaic levees, thus severely limiting human activities in the plain. From ca. 2000 to 800 cal. BC, a phase of shallow marine presence prevailed and constrained settlement on higher ground, forcing abandonment of the major part of the plain. Finally, since the eighth century BC, the sea has regressed southward and created the modern landscape