Early Subboreal Research Articles

Highly productive fishing in Lake Onega? New data on the subsistence basis of the Late Stone age populations in Russian Karelia

Recent excavations of the site of Fofanovo XIII (ca. 3500 to 3000 cal BC) on the western shore of Lake Onega, Russian Karelian, yielded evidence of production of Russian Karelian axes and adzes, as well as a rich faunal assemblage. Consisting mainly of unburnt bones, this assemblage represents a rare occurrence in Karelia and the neighboring regions of Russia and Finland, and sheds light on the subsistence of the Late Neolithic / Eneolithic populations of the Lake Onega. Fish bones overwhelmingly dominate, indicating a primary reliance on aquatic food resources, with the most common species being zander (over 80 %) and pike (ca. 9 %). In the specific natural conditions of the Early Subboreal in Lake Onega, zander was the species that could yield the maximal return of the invested effort, and this caused a very narrow specialization of fishing activities. The stable food supply provided by fishing favored tendencies towards complexity, which are evident through studies of the Russian Karelian industry. The analysis of the annual rings of zander vertebrae indicates that the site was in use during the snowless season. The identification of ringed seal, Atlantic sturgeon, and Wels catfish, which are not present in the lake nowadays, are also important results of the analysis.

Origin and Holocene geomorphological evolution of the landslide-dammed basin of la Narse de la Sauvetat (Massif Central, France)

This work is the first geomorphological analysis of La Narse de la Sauvetat, a hydromorphic basin located in the southern Limagne plain (French Massif Central) which had never been studied despite its great palaeoenvironmental interest. We explore the potential of its sedimentary archives to provide valuable data on Holocene geomorphic dynamics and their sensitivity to local and regional hydro-climatic changes. In order to characterize the nature and the morphostratigraphic and pedosedimentary evolution of the basin, we used an integrative approach involving geomorphological mapping, hand auger stratigraphic cross-sections, topographic analysis based on LiDAR data and stereophotogrammetric reconstruction, geophysical prospection and radiocarbon dating. Results revealed a palaeotopography fossilized under 6 m of sedimentary infilling, with a clear shift from fluvial to hydromorphic conditions circa 2800 cal BCE, separated by a level with colluvial and lacustrine features. A detailed analysis of the eastern border of the basin also suggests the existence of a former open valley in place of the current closed depression, now locked in by a topographic threshold forming a dam. The sedimentary aggradation of the basin started with an alluvial phase during the Upper Pleistocene and probably continued into the Middle and Late Holocene, consistently with regional alluvial dynamics. In the early Subboreal, a massive landslide occurred on the western slopes of the Puy-de-Corent volcanic plateau, thereby damming the valley and forming a closed depression. This episode coincided with the mid-Holocene climatic shift and an associated phase of slope instability and increased landslides in Western Europe due to changing climatic conditions. This depression evolved into a hydromorphic basin with several high energy hydro-sedimentary episodes after 2800 cal BCE; however hydro-sedimentary conditions gradually became more stable towards the Late Holocene. Around 500 cal CE, the drainage deteriorated towards palustrine conditions and caused the formation of a marsh and its consequent evolution into a shallow lake throughout the Middle Ages. This lake was drained in the late XVIIIth Century. The long-term sedimentary record of La Narse de la Sauvetat, sensitive to climatic instability periods of the Middle Holocene, makes this landslide-dammed basin a valuable site with an important potential to further development of palaeoenvironmental and geoarchaeological studies.

Late Pleistocene and Holocene environmental changes recorded in deposits of the Bukovynka Cave (the East-Carpathian foreland, Ukraine)

A study of pollen, fossil mammals and lithology (including grain-size analysis) of the terrigenous deposits in the Bukovynka Cave enables the reconstruction of the environments of several geochronologic subdivisions of the Middle Pleniglacial, Late Glacial and Holocene. A comparison of pollen assemblages in surface samples from the cave deposits and from the soils prove the importance of cave palynology for palaeovegetation reconstruction. The same patterns were shown by a comparison of pollen from hyaena coprolites in the cave and their enclosing sediments. In the Trapeznyi Chamber record, the two interstadials and one stadial identified are correlated with those of the Moershoofd interval, and the following stadial (after 41,000 yrs BP) is compared with the Hosselo stadial of Western Europe. In the Sukhyi Chamber record, Late Glacial times (around 10,700 yrs BP) differed from the Holocene in having a much harsher climate (with the spread of boreal forest). During the Holocene, a relatively wet phase, transitional from Atlantic to Early Subboreal, was separated from the similar phase of the Late Subboreal (2800 yrs BP) by a drier Middle Subboreal (with the disappearance of water-loving trees and the existence of steppe rodents). The Subatlantic was the wettest time, with culmination of a broad-leaved flora in the Roman (2300–1800 yrs BP) and Medieval (1000 yrs BP) Warm Periods. The cultivation of Cerealia started from 2800 yrs BP, and forest clearances increased after the Medieval Warm Period.

Holocene aeolian dynamics in the European sand‐belt as indicated by geochronological data

Aeolian sands are widespread in the European sand‐belt. While there is a consensus about the timing of increased aeolian activity and, in contrast, of surface stabilization during the Lateglacial, knowledge about Holocene aeolian dynamics is still very sparse. It is generally assumed that aeolian processes have been closely connected to human activities since at least the Neolithic period. A compilation of 189 luminescence dates from aeolian sands of Holocene age and 301 14C‐dates from palaeo‐surfaces, comprising palaeosols, buried peats and archaeological features from the whole sand‐belt, is plotted as histograms and kernel density plots and divided into sub‐phases by cluster analysis. This is also done separately for the dates from the areas west and east of the river Elbe. Our results show that aeolian activity did not cease with the end of the Younger Dryas but continued in the whole European sand‐belt until the Mid‐Atlantic (c. 6500 a BP), presenting evidence of vegetation‐free areas at least at the local scale. During the subsequent time period evidence of aeolian sedimentation is sparse, and surface stabilization is indicated by a cluster of palaeo‐surfaces ascribed to the early Subboreal (c. 5000 cal. a BP). The agglomeration of luminescence ages around 4000 years is probably connected with intensified land use during the Late Neolithic. Younger phases of aeolian sedimentation are indicated by clusters of luminescence ages around 1800 years, a group of luminescence ages from the Netherlands and NW Germany around 900 years, and a group of ages around 680 years in Germany. Among the dates from palaeo‐surfaces, clusters were identified around 2700, 1300 and 900 cal. a BP as well as around 690 cal. a BP in the western part and 610 cal. a BP in the eastern part of the sand‐belt. The clusters within the luminescence ages and the 14C‐dates coincide with phases where increased human impact can be deduced from archaeological and historical sources as well as from environmental history.

Holocene lake sedimentation in the steppe zone of southeastern Transbaikalia ( exemplified by the sediments of Lake Zun-Soktui)

Data on lacustrine sediments permitted reconstructing climate and vegetation changes in the steppe zone of southeastern Transbaikalia in the Holocene and the evolution of Lake Zun-Soktui. Also, changes in the size of the lake water plane have been reconstructed. A shallow lake formed in place of an oxbow lake in the middle Boreal phase of the Holocene. In the Atlantic phase, the lake had maximum depth and area. In the late Boreal, early Subboreal, and in the second half of the Subatlantic phase, the lake underwent significant shallowing and sometimes dried up for a short time. In the middle Boreal and Atlantic phases, the aridization decreased considerably. It has been established that pine forest belts on the Onon high plain before the Subatlantic occupied several times more space than now.

Post–Glacial stratigraphy and palaeoenvironment of the northern part of the Curonian Spit, Western Lithuania

A complex study including palynological and diatom analysis, palaeontological investigation of molluscan fauna, carbonates analyses and radiocarbon dating was performed in the northern part of the Curonian Spit (Western Lithuania). Environmental changes were reconstructed during the Late Glacial and Holocene. Cold and dry climate, unstable soils, open habitats of tundra vegetation spread in the surroundings of the northern part of the Curonian Spit during the Younger Dryas. Birch was dominant. The relatively deep Baltic Ice Lake with a freshwater planktonic diatom complex existed. During the Preboreal and the beginning of Boreal forest (birch and pine) was not dense, and wetland development occurred in coastal areas. Forest spread rapidly in response to significant warming during Boreal time. A shallow freshwater Ancylus Lake nearshore environment existed in the area of the northern part of the present Curonian Spit. The surrounding forest was dominated by broad-leaved species, especially elm, lime and oak, during the Atlantic. Alder and hazel occurred everywhere. Pine forest was still widely represented in the area on sandy soils. Subsequently, the shallow Litorina Sea basin existed around the area. Spruce forest spread in the Early Subboreal. Climate was warm and relatively dry, and intensive soil formation took place. Shallow brackish Postlitorina Sea lagoonal environmental conditions existed in the first half of Subboreal. Aeolian sand with buried soil formation started to accumulate at the end of Subboreal, and the northern part of the Curonian Spit became land.

Holocene recolonization and extinction of the pond turtle, Emys orbicularis (L., 1758), in Europe

We reconstruct the Holocene range fluctuations of the European pond turtle (Emys orbicularis) for northern and Central Europe. Based on 529 subfossil records and radiocarbon dating of critical finds, we provide evidence that E. orbicularis experienced a rapid range expansion with Holocene warming. Phylogeographic data argue for a colonization of northern and Central Europe from a glacial refuge located in the south-eastern Balkans. Already in the Late Preboreal (9100–8600calBC) the species occurred in northern Central Europe and was widespread in Denmark and southern Sweden (Skåne) during the Boreal (8600–7100calBC). The maximum range extension occurred during the Holocene climatic optimum (Atlantic: 7100–3750calBC), with records in southern England, middle Sweden, and northern Estonia. After the early Subboreal (3750–1750calBC) northern populations collapsed, coinciding with a climatic cooling and oceanization. Northern populations were most likely established via long distance dispersal (rafting using rivers debouching in the North and Baltic Seas); after northern Europe was reached, a minimum dispersal of 50km per 100 years may be hypothesized for the Boreal.

Holocene tidal back-barrier development at decelerating sea-level rise: a 5 millennia record, exposed in the western Netherlands

A succession of tidal back-barrier deposits, ranging in age from about 6000 to 0 cal BC, was recently exposed in an up to 17-m-deep excavation in the western Netherlands. The lower part of the succession shows the flooding of the area and the establishment of a tidal back-barrier basin during high rates of relative sea-level rise; the upper part of the succession consists mainly of estuarine channel and tidal flat deposits. Medieval lake deposits cover the estuarine sequence. The development of the Holocene Holland Tidal Basin took place in the Atlantic and Early Subboreal sub-stages between ∼7000 and 3500 cal BC after which the tidal inlets closed and fresh water marshes developed. Its evolution was largely controlled by both the rates of sea-level rise and of sediment supply. All the sediment was derived from the North Sea and the shoreface. During initial flooding of the outcrop area, the rate of sea-level rise (0.1–0.06 cm/year) far outran that of sediment supply. Facies zones developed controlled by the inundated topography and sediment supply. Fresh water reed marshes evolved along the landward side of the tidal basin. The Basal Peat that formed in these marshes is overlain by a thin layer of organic-rich clays, which represent the deposits in a lagoon separating the marshes from the tide-influenced sands and clays of the proximal zone of the tidal basin. The latter consisted of sand-rich channel sequences separated by mud-rich interchannel areas. Position of the channels was controlled by the pre-existing topography; the channels were confined by levees consisting of overbank and crevasse deposits. The interchannel areas consisted of sub-tidal mudflats. The studied outcrop showed a subtidal fan or delta, connecting a non-exposed channel to a mud-rich sequence of subtidal interchannel sediments. The latter graded upwards into inter- and supratidal flats deposited when the rate of sea-level rise decelerated after ±5000 cal BC and sediment supply eventually outran the creation of accommodation space. This sequence is overlain and incised by an estuarine system of mainly Subboreal and Subatlantic age with well-developed inclined heterolithic stratification showing in particular the equilibrium variations of the channel system under influence of changing storm/fair weather conditions. The excavation shows an almost complete succession of the channel, from its origin to its final abandonment stage with a number of different channel sub-facies. Upwards, the pointbar deposits merge into intertidal flats. A thin veneer of medieval lake deposits overlies the latter.

Records of climatic changes in the carbonate profiles of Russian Chernozems

The carbonate profiles of Chernozems bear important information on soil processes and can be successfully used for paleoenvironmental reconstruction. In the Northern Caucasus region, Russia, carbonate profiles of Chernozems were compared under anthropogenic (irrigation) and natural changes of moisture regime. The results for irrigation served as the basis for understanding the response to natural climatic changes. A soil chronosequence, consisting of soils buried under archaeological mounds dated to >5000, 3800–4000 and 1600–1700 BP and modern surface soils, was studied in a similar way. The soils buried >5000 and 3800–4000 BP had distinctive migrational and segregational carbonate accumulations (CAs). The migrational forms occurred in the surface horizons and contained 89–92% calcite with the highest dissociation temperatures. In the soils buried 1600–1700 BP the carbonate profile was clearly defined in terms of migrational CAs; they occurred only in the deeper horizons, had no clear boundaries and were diffused throughout the soil mass. In the modern surface soils the migrational CAs have almost disappeared, and the segregational CAs have the largest halos of recrystallised carbonates. The values of δ 13C for CAs in the soils buried >5000 and 3800–4000 BP were lighter than in the soils buried 1600–1700 BP and the modern surface soils (−10.6‰ to −9.9‰ and −9.6‰ to −8.8‰, respectively). We conclude that the climate of the region during the second half of the Holocene changed from relatively dry and warm in the Atlantic period (>5000 BP) to more humid and cooler in the early Subboreal (5000–4000 BP). Since 4000 BP the climatic conditions have remained relatively stable with some changes in moisture regime resulting from human activities in recent centuries.

A radiocarbon dated Holocene pollen profile from the Banat mountains (Southwestern Carpathians, Romania)

A 1.6 m peat profile from the Semenic (1400 m a.s.l., Banat, Romania) was investigated by pollen and plant macrofossil analysis and dated by radiocarbon datings. The Holocene vegetation history is dominated by Pinus in the Preboreal, by Corylus and Mixed Oak Forest from the Boreal to the Middle Atlantic, by Picea and Mixed Oak Forest in the Late Atlantic, by mainly Carpinus in the Early Subboreal and mainly Fagus from the Middle Subboreal onwards. The first human impact can be recognized in the Bronze Age, together with the Fagus expansion.

Reconstruction of hydrological changes between 7000 and 3000 BP in the upper and middle Vistula River Basin, Poland

Rhythmic fluctuations in the hydrological regime are demonstrated based on a review of records sensitive to relative climatic stability between 7000 and 3000 BP in the upper and middle parts of the Vistula River Basin, central Europe. In the fluvial deposits and landforms these variations are very clear; phases of higher flood frequency are dated 6600-6000, 5500-4750, 4500-4100 and 3250-3000 BP. These phases coincide very well with sparse information on landslides, data on high lake levels in the early Subboreal, phases of forest-ecosystem transformation and, finally, the reaction of human cultures to these changes. Their rhythmicity correlates well with records from the Alps and the Alpine foreland but poorly with those from Scandinavia. This may be explained by changes in the zonal pattern of air- mass circulation. Among the causes of the humid phases, it is the frequency of volcanic eruptions which should be taken into consideration.

Early and middle Holocene vegetational development in Kurarp (Scania, South Sweden)

A 9 m core from Kurarp, northwest of Ystad, is investigated palynologically. It covers the early and middle part of the Holocene and has high resolution for the Atlantic and Early Subboreal allowing a detailed investigation of the vegetational development for the period. During the early Holocene the various trees of the mixed deciduous forest immigrated and during the Early Atlantic there was forest around the lake at Kurarp. During the Late Atlantic and Early Subboreal there are changes in the pollen values of various trees together with the occurrence of various herbs and it is suggested that there was a gradually increasing stress on the forest, induced, at least partly, by people's use of the area. Some aspects of mutual relationships etween human activity and vegetational development are outlined. Based on theoretical consideration possible reasons for subtle vegetational changes are put forward and brief discussions are given on early cultivation of cereals in Europe, fodder for domestic animals and the cause of the elm decline.

Transgression of a raised bog across a coversand ridge originally covered with an oak—lime forest: Palaeoecological study of a Middle Holocene local vegetational succession in the Amtsven (northwest Germany)

A section representing the closing phase of the Atlantic and the Early Subboreal was examined at centimeter intervals for all kind of micro- and macrofossils. The section was taken on the slope of a Pleistocene coversand ridge in the SE margin of the Amtsven (northwest Germany). During the Atlantic large areas of forest were replaced by raised-bog vegetation. In the Late Atlantic and the Early Subboreal the area surrounding the coversand ridge became gradually wetter due to a rising water-table resulting from an approaching and ultimately transgressing bog. Locally, a Quercus-Tilia forest persisted till the Early Subboreal on account of its more elevated situation on the coversand ridge, but when the water table continued to rise the Quercus-Tilia forest gradually developed, within a time-span of about 400 yrs., into a raised bog through various successive vegetational phases.

A palaeoecological study of holocene peat bog sections in Germany and The Netherlands, based on the analysis of pollen, spores and macro- and microscopic remains of fungi, algae, cormophytes and animals

A Holocene peat section of the Engbertsdijksveen (The Netherlands) was analysed at centrimetre intervals for all kinds of micro- and macrofossils in order to obtain maximum information regarding local vegetation and animal succession and regional changes in the prevailing vegetation types. The analysed micro- and macrofossils are illustrated, described and interpreted. Among them are about 70 fungal taxa, about 25 animal taxa, at least 4 algae, and about 15 fossils of unknown identity or origin. The taxonomic designation, matrix, host- or substrate specificity and indicator value of representatives of five different groups of fossils have been tabulated. The fruit-bodies of several taxa distinguished as spore types were found during the macrofossil analysis, e.g., ascospores, mycelium and fruit-bodies of the parasite Meliola cf. niessleana (Type 14) are present in the levels in which Calluna vulgaris played a role in the local vegetation. The ascomycete Geoglossum sphagnophilum was, according to its spore distribution, a common element in the bog vegetation during the Atlantic and Subboreal periods. Zygospores of Mougeotia cf. gracillima (Type 61) and other Zygnemataceae indicate the levels where these algae could grow during the local succession in the peat bog. The zygospores indicate phases of shallow, stagnant, mesotrophic open water during spring. Conventional analysis of pollen and macro-remains with a high resolution in time (centimetre diagrams), the above-mentioned new information, and the correlation of events inside and outside the site of the peat bog lead to the following main conclusions: The Atlantic-Subboreal transition, well known for its elm decline, could be correlated with a local change in bog vegetation. Following the alteration of wet Scheuchzeria palustris vegetation with hummock vegetation in the Atlantic period, the appearance of a Molinia coerulea peat coincides with the elm decline. According to the present ecology of M. coerulea, this change must have been caused by a seasonally recurring, considerable lowering of the groundwater level during summer. During winter the groundwater rose so far that in spring shallow open water prevailed and Mougeotia cf. gracillima could develop. This local vegetational succession indicates an unstable climatic period with pronounced dry seasons during the early Subboreal. During the climatic deterioration of the Subboreal-Subatlantic transition the incidence of Corylus avellana decreased. The Corylus pollen curve shows several cyclic fluctuations during this period (1400-600 B.C.). Depressions in the Corylus pollen curve correspond with particularly wet local vegetation (more oceanic, possibly cooler phases), Corylus pollen maxima correspond with relatively dry bog vegetation (less oceanic, possibly warmer phases). These cyclic fluctuations correspond to approximately 150–200 historical years each. The increasing oceanicity ultimately resulted in the formation of peat by Sphagnum species of the section Cymbifolia. In this Subatlantic Cymbifolia peat the fluctuations of the minor constituent Sphagnum cf. rubellum are clearly correlated with the fluctuations of the curve of the rhizopod Amphitrema flavum. This phenomenon is interpreted as a reflection of more and less oceanic phases during the Subatlantic period. All available data were expressed in curves, in order to indicate changes in local and perhaps regional moisture conditions. Ther percentages of plants indicating human influence are relatively low during the Neolithic and Bronze Age. During the Iron Age the influence of prehistoric man was relatively important. Secale cereale was already grown during the secondary century B.C. Population density decreased again during the second century A.D. The present study is intended as a first step towards a more detailed knowledge of the changing ecosystems of bogs and forests and in their response to changing environmental factors, such as minor and major climatic cycles.