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This paper presents an integrated approach to assess Holocene environmental changes in the Sperchios delta, Sperchios rift, central Greece. A multidisciplinary study was carried out applying established analytical methods as well as exploring new techniques to detect past environmental conditions in a fluvio-deltaic depositional system. A series of six deep boreholes, up to 50 m long, and four shallow cores, up to 6 m long, from across the delta plain, were studied in detail. Sedimentary facies were defined by changes in grain size and macro- and microfaunal composition. Variability in mineral magnetic composition documented by changes in bulk magnetic susceptibility (χ and χ77K/χ293K) and remanence parameters (S−300 and σARM/σSIRM ratios), as well as down-core elemental variations obtained by scanning micro-x-ray fluorescence (µ-XRF), provide constraints on the depositional changes related to the evolution of the Sperchios delta. Correlations between elemental data derived by µ-XRF analyses and grain size were also analyzed and used to further constrain the facies interpretation. Overall, these Holocene sediments reveal a transgressive–regressive succession overlying pre-transgressive terrestrial deposits of Late Pleistocene–Early Holocene age. Furthermore, 13 new 14C radiocarbon dates constrain the transgression rate to be ~3.5 m/yr for the Early Holocene and the regression rate to be ~1 m/yr for the Late Holocene. The Sperchios delta plain developed when the rate of sea-level rise decreased ~6000 cal. yr BP as it has been proposed for the broader area of Aegean Sea. This study demonstrates that the combination of techniques used here provides a powerful way to map out paleoenvironmental changes and thus the 3D stratigraphic architecture of Holocene sedimentary successions. [ABSTRACT FROM AUTHOR]

The reconstruction of millennial-scale interactions between ecosystems and societies can provide unique and valuable references for understanding the creation of cultural landscapes and help elucidate their value, weaknesses and legacies. Among the most emblematic forms of Mediterranean land use, olive groves and pastoralism have occupied a prominent place. Therefore, it is vital to know when, how, and with what ecological consequences these practices were established and developed. Located in the southern part of the Aegean Sea, Crete is the largest island of Greece. The island is characterised by a long human history of land use, but our understanding of past environmental changes for the entire Holocene is fragmentary. This paper presents a new investigation of Lake Kournas in Crete, where recent coring provided a 15-m sequence covering ten millennia of land cover and land-use history. The study of this new core involves the analysis of the sediment dynamics, flood deposits, pollen, diatoms, fungal and algal remains, and microcharcoals. Results show that ecosystem development near Lake Kournas was not a linear process. They reveal linkages and feedbacks between vegetation, biodiversity, fire, human impact, erosion, and climate change. A possible human occupation and agro-pastoral activities around the lake may have been detected as early as 9500 cal BP, perhaps in a transitional phase between the Mesolithic and the Neolithic. At 8500 cal BP, climatic conditions may have promoted the expansion of the evergreen oak woodland. However, human impact was probably the most important driver of ecosystem change with the establishment of an agro-system after 8000 years ago. Thereafter, the trajectory of Kournas' lake and catchment ecosystems from the Mid to Late Holocene follow the rhythm of land-use change. Among the traditional Mediterranean land uses, olive cultivation locally played a major role in the socio-ecosystem interactions, providing economic benefits but also destabilising soils. During the last six millennia, three main phases of olive cultivation occurred during the Final Neolithic-Minoan period, the Hellenistic-Roman-Byzantine (HRB) period and Modern times. Along with the changing land use under the successive political and economic influences rules, the resilience capacities of vegetation permitted it to shift back to higher biodiversity again after decreasing phases. Forest vegetation was always able to recover until the onset of the Venetian period (13th century), when woodlands were dramatically reduced. Only during the past century has forest vegetation slightly recovered, while the flood regime had already been altered during previous centuries. During the past 100 years, biodiversity markedly declined, probably in response to the industrialization of agriculture. • The Lake Kournas core study includes sediment, pollen, NPP, diatom and microcharcoal analyses. • The results reveal almost ten millennia of interactions between climate, human activities, erosion, vegetation and fire. • Climate may have been involved in the first shift around 8500 cal BP that promoted expansion of evergreen oak woodland. • From the Mid to the Late Holocene, the ecosystem trajectory near the lake rather follows the rhythm of land use changes. • Among the traditional Mediterranean land uses, olive cultivation locally played a major role. [ABSTRACT FROM AUTHOR]

Abstract: This paper deals with Holocene coastal changes of the Astakos plain in Akarnania, NW Greece. Palaeoenvironmental scenarios are based on the analysis of the lateral and vertical distribution patterns of sedimentary facies. Sediments from vibracorings were studied using geomorphological, sedimentological, microfaunal, palaeobotanical and geochemical methods. A geochronostratigraphy was achieved by 14C-AMS-dating of organic matter. We present palaeogeographical maps for different points in time since the mid-Holocene. The evolution of the coastal area was generally controlled by the migration of a complex system of a shallow marine embayment, an adjacent lagoonal environment and an adjoining coastal lake forced by the interaction of sea level rise, tectonic movements, and sediment supply from the hinterland. The maximum transgression of the Ionian Sea took place at circa 5500cal BC reaching approx. 1.1km inland. The lagoon as well as the coastal lake had their largest dimensions around 4500cal BC indicating a more humid climatic period. In the course of a long-lasting regression, an asymmetric sedimentation pattern developed. Around 2500cal BC it was characterized by strong fluvial deposition of the Xeropotamos in the western plain and a small and narrow marine embayment with associated lagoonal to limnic coastal water bodies in the eastern plain. The latter were related to karstic springs draining the adjacent Rigani ridge. Around 500cal BC the coastline lay about 200m landward of its present position. Possible harbour sites for the ancient polis of Astakos are (a) the area of modern Astakos where a mole in a position seawards of the present coast would have guaranteed deep water conditions for anchoring, or (b) the southeastern fringe of the plain where deep water prevailed and the nearby freshwater outlet protected the site from rapid siltation. We found increased torrential activity (i) for the 6th–5th millennium BC, (ii) for the 2nd half of the 1st millennium BC until Roman times, and (iii) at the end of the 19th century AD. At least the two younger phases are mostly due to anthropogenic soil erosion. Between the 4th and the 2nd millennium BC a period of ecological stability existed. Relative changes in sea level for the Bay of Astakos were reconstructed for the first time. Since the mid-Holocene, the relative sea level has never reached a higher position than today. It rose from 12.50m b.s.l. at 6200cal BC via 2.20m b.s.l. at 500cal BC to its present level. Besides eustatic reasons, tectonic subsidence due to the half graben structure of the area is the main trigger of the relative rise in sea level. [Copyright &y& Elsevier]