The question of the origin of Alpine farming and pastoral activities associated with seasonal ver... more The question of the origin of Alpine farming and pastoral activities associated with seasonal vertical transhumance and dairy production in the Silvretta Alps (Eastern Switzerland) has recently benefitted from renewed interest. There, pastoral practises began during the Late Neolithic (2300 BC), but alpine dairy farming was directly evidenced so far only since the Late Bronze Age/Early Iron Age (1300–500 BC). The vegetation development, timberline shifts at 2280 m a.s.l. and environmental conditions of the subalpine Urschai Valley (Canton of Grisons, Switzerland) were reconstructed for the small (8 m2) Plan da Mattun fen based on palynological and geochemical analyses for the last six millennia. The X-ray fluorescence (XRF) analyses are among the first ones performed on a European peatland in such altitudes. A high Rb/Sr ratio in the fen peat sediments revealed an increase in catchment erosion during the time when the forests of the Upper Urschai Valley were steadily diminished probably by fire and livestock impact (2300–1700 BC). These landscape openings were paralleled by increasing micro-charcoal influx values, suggesting that prehistoric people actively set fire on purpose. Simultaneously, palynological evidence for pastoralism was revealed, such as pollen from typical herbs indicating livestock trampling, and abundant spores from coprophilous fungi. Since then, vertical transhumance and pastoral activities remained responsible for the open subalpine landscape above 2000 m a.s.l., most probably also in the context of milk and dairy production since 1300 BC, which is characteristic for the European Alps until today.
A high quantity of well-dated, high-resolution, continuous geoarchives is needed to connect palae... more A high quantity of well-dated, high-resolution, continuous geoarchives is needed to connect palaeoen-vironmental reconstructions with socio-environmental and cultural transformations in a geographi-cally heterogeneous region such as southern Greece. However, detailed and continuous palaeoclimaticand palaeoenvironmental archives from the NE Peloponnese are still sparse. Here, we present two newpalaeolake archives of Pheneos and Kaisari covering the last 10 500 and 6500 years, respectively. Forthe last 5000 years, we compare them with sediment records from adjacent Lake Stymphalia and the Asea valley by applying the same set of sedimentological, geochemical, and statistical analyses to allfour lacustrine archives. Continuous geochemical X-ray fluorescence (XRF) core scanning records provide evidence forhydrological variations and environmental changes since the Early Helladic period (5050 BP), thebeginning of the Bronze Age in Greece. We hereby focus on different spatial scales to estimate thevalidity range of the proxy signals. Ten elements were selected (Al, Si, K, Ca, Ti, Mn, Fe, Rb, Sr,Zr) for a principal component analysis. The clr(Ca/Ti) was chosen as the most meaningful proxy,reflecting varying input of carbonaceous vs. clastic input, which may be linked to changes in the hy-drological conditions. Our results show phases when permanent lake water bodies existed (ca. 5000–3600 cal BP) as well as phases with periodic desiccation of the lakes during younger times. WhilePheneos and Kaisari show a drying trend during the transition phase from the Late Helladic periodto the Proto-Geometric period (ca. 3200–2800 cal BP), Stymphalia and Asea show a rather short drypeak around 3200 cal BP followed by a wetter phase.
This paper aims at reconstructing the palaeoclimatic changes during the last 2600 years in southe... more This paper aims at reconstructing the palaeoclimatic changes during the last 2600 years in southern Greece based on a proxy record from Lake Trichonida. For the first time, we provide a reliable age-depth model and continuous geochemical data for the largest and deepest lake in Greece. We use X-ray fluorescence (XRF) geochemical data supported by discrete mineral analysis based on X-ray diffraction (XRD), grain size distribution, and organic matter content to investigate changes in the lake sedimentary system and identify the major forcing mechanisms. A principal component analysis based on the XRF geochemical composition identifies the variation between carbonate-rich material, precipitating predominantly under drier and/or warmer conditions, and terrigenous sediment input, with it being more prominent during wetter and/or colder conditions. The first principal component (PC1) shows a very strong correlation with the weathering proxy log(Rb/Sr), and we interpret both proxies as depicting fluctuations in the hydrological conditions. A cluster analysis, conducted on the continuous geochemical and colour parameters, highlights the similarities in the sediment charac-teristics deposited during wetter phases, notably during 1850–1750, 1500–1400, ca. 1100, and ca.100 cal BP. ...
Herkules kämpfte an der Karstquelle von Lerna gegen Hydra, ein Wasserungeheuer, wie der Name scho... more Herkules kämpfte an der Karstquelle von Lerna gegen Hydra, ein Wasserungeheuer, wie der Name schon sagt. Im Einzugsgebiet dieser Quelle, dem stymphalischen See, einer Karstpolje mit einem beeindruckenden Schluckloch, befreite er die Bewohner der Gegend von mörderischen Vögeln. Und einen Schritt weiter den Göttern entgegen, auf dem Berg Ziria, dem „Wassersammler“ für den stymphalischen See, befindet sich die Geburtshöhle des Götterboten Hermes, angefüllt mit Tropfsteinen von unglaublicher Schönheit. Die unterschiedlichen Erscheinungsformen des Karst prägen an vielen Stellen die Landschaft des Peloponnes und haben seit jeher die Phantasie der Menschen beflügelt. Der populärwissenschaftliche Artikel führt auf dem Pfad zwischen Phantasie und Forschung auf eine spannende Entdeckungsreise durch die Region.
In this study, we present a modeling approach that investigates how much cultivable land was requ... more In this study, we present a modeling approach that investigates how much cultivable land was required to supply a society and whether societies were in need when environmental conditions deteriorated. The approach is implemented for the NorthEastern Peloponnese and is based upon the location of Late Helladic IIIB (1300-1200 BCE) archaeological sites, an assessment of their sizes, and a proposed diet of the people. Based on these information, the areal requirement of each site is calculated and mapped. The results show that large sites do not have sufficient space in their surroundings in order to supply themselves with the required food resources and thus they depended on supplies from the hinterland. Dry climatic conditions aggravate the situation. This indicates that potential societal crisis are less a factor of changing environmental conditions or a shortage of arable land but primarily caused by socioeconomic factors.
Lacustrine sediments generally record landscape development in the lake's catchment area controll... more Lacustrine sediments generally record landscape development in the lake's catchment area controlled by palaeoclimatic and human induced changes. To improve our understanding on the anthropogenic and climatic influences on landscape development in Southern Greece for the last 2500 years, we report a 2 m-long, continuous high-resolution sedimentary record from shallow Lake Stymphalia (Peloponnese, Greece). Our proxies record climatically as well as anthropogenically induced landscape changes, influencing the lake area and lake depth.
The Classical-Hellenistic era reflects a moderate, stable Mediterranean climate with low sedimentation rates. The parallel existence of the highly populated, major ancient city of Stymphalos, on the contemporary lake edge, doesn't seem to have caused lasting alterations in the record. The construction of the Hadrianic Aqueduct in the Roman era, ca. 130 AD, however causes an influential transformation in the lake development. It has a lasting effect on the lake hydrology as well as the vulnerability of this ecosystem. During Late Roman times, 5th to 6th century cal AD, the abandonment of the aqueduct combined with cooler climate conditions allows lake levels to recover. A phase of very high climatic instability was identified for the subsequent Early Byzantine (EB) period, during the 7th and 8th century cal AD. For this period, the later phase of the Late Antique Little Ice Age (LALIA), our proxies indicate further cooling and highly fluctuating water availability in a rather small lake area. The Middle Byzantine (MB) Period (9th-12th century AD) is characterized by an over fivefold increase in sedimentation rates. Since local population was still well below Classical levels, we explain this singular period through an interaction of modest increase in land use but marked by careless management of deforested areas, warm and wet climatic conditions during the Medieval Warm Period and long-term effects of vulnerability caused by the aqueduct construction. Probably during this phase, the lake level rose through unparalleled sedimentary infill to flood and bury a significant part of the Lower Town of the abandoned ancient city. The Late Byzantine Period (13th and 14th century AD) sees core evidence for erosion of established, non-vegetated soils (high magnetic susceptibility), in a period of almost total depopulation. In the subsequent Ottoman era (late 15th – early 19th centuries AD) local settlement made only slight recovery, the climatic conditions seem less stable during the Little Ice Age (LIA) and the lake seasonally and later periodically starts to dry up, cumulating in a longer dry phase at the end of the 19th century AD, when agricultural activity on the polje floor was possible. The conclusion conforms with recent modelling of environmental change, critical of mono-causation, rather focussing on complex interactions of human and natural factors in the inception of landscape transformation.
In this study, we combine erosion and anthropogenic proxies (Ti, Pb) from calibrated portable XRF... more In this study, we combine erosion and anthropogenic proxies (Ti, Pb) from calibrated portable XRF with pollen and radiocarbon chronologies in peat from mires of the Kleinwalser Valley (Kleinwalsertal, Vorarlberg, Austria) to reconstruct palaeoenvironmental change and human impact in the northern central Alps. Favoured by a wetter climate, two analysed mires formed 6200 years ago in a densely forested valley. Landscape opening suggests that the first anthropogenic impact emerged around 5700 to 5300 cal BP. Contemporaneously, lead enrichment factors (Pb EFs) indicate metallurgical activities, predating the earliest archaeological evidence in the region. Pollen and erosion proxies show that large-scale deforestation and land use by agro-pastoralists took place from the mid- to late Bronze Age (3500 to 2800 cal BP). This period was directly followed by a prominent peak in Pb EF, pointing to metallurgical activities again. After 200 cal CE, a rising human impact was interrupted by climatic deteriorations in the first half of the 6th century CE, probably linked to the Late Antique Little Ice Age. The use of the characteristic Pb EF pattern of modern pollution as a time marker allows us to draw conclusions about the last centuries. These saw the influence of the Walser people, arriving in the valley after 1300 cal CE. Later, the beginning of tourism is reflected in increased erosion signals after 1950 cal CE. Our study demonstrates that prehistoric humans were intensively shaping the Kleinwalser Valley's landscape, well before the arrival of the Walser people. It also demonstrates the importance of palaeoenvironmental multiproxy studies to fill knowledge gaps where archaeological evidence is lacking.
Thermokarst lakes cover nearly one fourth of ice-rich permafrost lowlands in the Arctic. Sediment... more Thermokarst lakes cover nearly one fourth of ice-rich permafrost lowlands in the Arctic. Sediments from an athalassic subsaline thermokarst lake on Herschel Island (69°36′N; 139°04′W, Canadian Arctic) were used to understand regional changes in climate and in sediment transport, hydrology, nutrient availability and permafrost disturbance. The sediment record spans the last ~ 11,700 years and the basal date is in good agreement with the Holocene onset of thermokarst initiation in the region. Electrical conductivity in pore water continuously decreases, thus indicating desalinization and continuous increase of lake size and water level. The inc/coh ratio of XRF scans provides a high-resolution organic-carbon proxy which correlates with TOC measurements. XRF-derived Mn/Fe ratios indicate aerobic versus anaerobic conditions which moderate the preservation potential of organic matter in lake sediments. The coexistence of marine, brackish and freshwater ostracods and foraminifera is explained by (1) oligohaline to mesohaline water chemistry of the past lake and (2) redeposition of Pleistocene specimens found within upthrusted marine sediments around the lake. Episodes of catchment disturbance are identified when calcareous fossils and allochthonous material were transported into the lake by thermokarst processes such as active-layer detachments, slumping and erosion of ice-rich shores. The pollen record does not show major variations and the pollen-based climate record does not match well with other summer air temperature reconstructions from this region. Local vegetation patterns in small catchments are strongly linked to morphology and sub-surface permafrost conditions rather than to climate. Multidisciplinary studies can identify the onset and life cycle of thermokarst lakes as they play a crucial role in Arctic freshwater ecosystems and in the global carbon cycle of the past, present and future.
Fossils represent invaluable data to reconstruct the past history of life, yet fossil-rich sites ... more Fossils represent invaluable data to reconstruct the past history of life, yet fossil-rich sites are often rare and difficult to find. The traditional fossil-hunting approach focuses on small areas and has not yet taken advantage of modelling techniques commonly used in ecology to account for an organism's past distributions. We propose a new method to assist finding fossils at continental scales based on modelling the past distribution of species, the geological suitability of fossil preservation and the likelihood of fossil discovery in the field, and apply it to several genera of Australian megafauna that went extinct in the Late Quaternary. Our models predicted higher fossil potentials for independent sites than for randomly selected locations (mean Kolmogorov-Smirnov statistic = 0.66). We demonstrate the utility of accounting for the distribution history of fossil taxa when trying to find the most suitable areas to look for fossils. For some genera, the probability of finding fossils based on simple climate-envelope models was higher than the probability based on models incorporating current conditions associated with fossil preservation and discovery as predictors. However , combining the outputs from climate-envelope, preservation, and discovery models resulted in the most accurate predictions of potential fossil sites at a continental scale. We proposed potential areas to discover new fossils of Diprotodon, Zygomaturus, Protemno-don, Thylacoleo, and Genyornis, and provide guidelines on how to apply our approach to assist fossil hunting in other continents and geological settings.
Special Issue: Mediterranean Holocene Climate, Environment and Human Societies, Mar 15, 2016
Published archaeological, palaeoenvironmental, and palaeoclimatic data from the Peloponnese in Gr... more Published archaeological, palaeoenvironmental, and palaeoclimatic data from the Peloponnese in Greece are compiled, discussed and evaluated in order to analyse the interactions between humans and the environment over the last 9000 years. Our study indicates that the number of human settlements found scattered over the peninsula have quadrupled from the prehistoric to historical periods and that this evolution occurred over periods of climate change and seismo–tectonic activity. We show that societal development occurs both during periods of harsh as well as favourable climatic conditions. At some times, some settlements develop while others decline. Well-known climate events such as the 4.2 ka and 3.2 ka events are recognizable in some of the palaeoclimatic records and a regional decline in the number and sizes of settlements occurs roughly at the same time, but their precise chronological fit with the archaeological record remains uncertain. Local socio-political processes were probably always the key drivers behind the diverse strategies that human societies took in times of changing climate. The study thus reveals considerable chronological parallels between societal development and palaeoenvironmental records, but also demonstrates the ambiguities in these correspondences and, in doing so, highlights some of the challenges that will face future interdisciplinary projects. We suggest that there can be no general association made between societal expansion phases and periods of advantageous climate. We also propose that the relevance of climatic and environmental regionality, as well as any potential impacts of seismo-tectonics on societal development, need to be part of the interpretative frameworks.
A well-dated palynological record spanning the interval ~ 40,500–7060 cal yr BP, retrieved from a... more A well-dated palynological record spanning the interval ~ 40,500–7060 cal yr BP, retrieved from a peatland on the Leizhou Peninsula in south China, clearly shows regional vegetation and climate changes during the last glacial period. Pollen data showed that the study region was mainly covered by subtropical evergreen trees during Marine Isotope Stage 3 (MIS 3), indicating a subtropical climate with relatively high temperature and precipitation. During MIS 2, subtropical evergreen-deciduous forest with large areas of grassland occurred, implying cooler and drier conditions. Some tropical forest elements increased during the early Holocene, indicating a warm and wet trend. Several millennial-scale oscillations of the pollen records appeared to correlate with the cold anomalies in the North Atlantic region. Our records agree well with many records from other regions, but they are a bit different than that inferred from the neighboring Huguang Maar Lake. Furthermore, our results suggest that the vegetation surrounding Xialu peatland was strongly influenced by the migration of the intertropical convergence zone (ITCZ) and variability in the East Asian summer monsoon (EASM). Changes of atmospheric CO2 concentration (pCO2) levels may have also affected the long-term vegetation changes in the study region
Here, we present a well-dated terrestrial charcoal chronology covering the interval ~ 41,000–7050... more Here, we present a well-dated terrestrial charcoal chronology covering the interval ~ 41,000–7050 cal BP and identifying the millennial-scale variability in biomass burning for the tropical Leizhou Peninsula, south China. Our results show that changes in biomass burning closely followed regional temperature and precipitation variations on orbital timescales, i.e., more biomass burning occurred during the warm/wet Marine Isotope Stage (MIS) 3, and less biomass burning occurred during the cold/dry MIS 2. Superimposed on this general trend, our charcoal record shows millennial-scale variability in biomass burning corresponding to the rapid climate changes associated with Dansgaard–Oeschger (D–O) cycles, i.e., biomass burning increased during D–O warming events, whereas biomass burning decreased during intervals of rapid cooling terminated by Heinrich events. During the cooler/drier periods, low biomass burning can be explained by the decline of vegetation productivity, whereas the warmer/wetter periods are characterized by higher biomass burning related to increasing fuel availability. Therefore, climate control can be considered as the major forcing factor of biomass burning from 41,000–7050 cal BP on both orbital and millennial timescales in the northern Leizhou Peninsula.
As part of the lagoon barrier accretions plain characterizing the NW coast of the Peloponnese, th... more As part of the lagoon barrier accretions plain characterizing the NW coast of the Peloponnese, the Kotychi Lagoon is believed to
have formed in the prograding delta of the Palaeo-Peneus River over 7000 years ago. Geochemical/sedimentological proxies-data
(XRF, grain size, OC-, IC-, C/N-analysis) combined with Bayesian age-depth-modeling revealed that from 8500 to 8000 cal BP
marine conditions were prevailing. Around 8000 cal BP, a short-lived sequence of coastline progradation and barrier accretion
created lagoonal conditions. Thus, the first chronological control for the onset of lagoon formation in coastal Elis is presented.
Pronounced lagoonal conditions developed approximately 6300 cal BP, simultaneously to the period of circum-Mediterranean
lagoon formation. A rapidly varying sedimentary record indicates a phase of geomorphological instability between 5200 and 3500
cal BP terminating with the erosional unconformity of a river channel. This evolution reflects a two-phase development: (1) Early
Holocene morphology was controlled by the postglacial sea level rise; (2) with receding of the ice sheets by mid-Holocene, the
preeminent role of the eustatic signal was overwhelmed giving local and regional processes, such as human-induced soil erosion
and climatic forcing an accentuated role. Thus, the evolution of the Elean coastline shows analogies to circum-Mediterranean
lagoon formation.
Before the arrival of the Spaniards in Peru in 1532, many different societies flourished in the c... more Before the arrival of the Spaniards in Peru in 1532, many different societies flourished in the coastal desert of southern Peru. Of these, one of the best known is the Nasca culture (living in the area between about 260 cal BC and 640 cal BC.), which created the famous geoglyphs on the desert floor. In this paper we present a numerical chronology for the cultural development in the valleys of Palpa, in the northern part of the Nazca region, which spans the time from the Archaic Period (starting there around 3760 cal BC) to the Late Intermediate Period (terminating with the arrival of the Spaniards in 1532 AD). The chronology is based on more than 150 14C samples collected by our project from well-documented archaeological excavations of 17 different sites in and around Palpa. Thanks to the advanced AMS-14C dating technique, demanding only few milligrams of organic material, we could focus on samples of plants, like beans, corn, or reed, representing single years of growth or use, and also on delicate materials like straw from clay bricks (adobe) and textiles. All single 14C dates were combined to cultural phases using a Bayesian statistical model, implementing the a priori information of the archaeological contexts, and adopting the relative ceramic chronologies available for this area.► We present a numerical chronology for the cultural development in the valleys of Palpa (South Peru). ► More than 150 radiocarbon dates and archaeological age information are combined in a Bayesian model. ► The chronology covers the time from 3720 cal BC (start Archaic Period) to 1532 cal AD (end Late Intermediate Period).
The Gulf of Corinth and the northern part of the Peloponnesus/Greece, an area of asymmetric grabe... more The Gulf of Corinth and the northern part of the Peloponnesus/Greece, an area of asymmetric graben structure, step faults and tilted blocks, is one of the most active seismic zones in the world. Six major faults are known to be most responsible for the historic and present seismic activities in the area of Aigion. Our study focuses preliminarily on the area around the Aigion fault, whose trace runs E-W through the harbour of Aigion. Investigations of the stratigraphic sequence, tectonic structure and hydrogeologic conditions of the southern Corinth graben shoulder and first drilling activities there, have started in summer 2001. From July until September 2002 the International Continental Deep Drilling Project (ICDP) and the EU Project DGLab-Gulf of Corinth drilled the AIG10 borehole in the harbour of Aigion to a total depth of 1001 m. Our investigations in this ICDP/EU framework are aimed at studying the thermal-hydraulic conditions on the southern graben shoulder. Here we report the first results on sampling and hydraulic testing. The deep AIG10 borehole has successfully cored in approx. 760 m depth the fault plane, which separates fractured radiolarite in the hanging wall from highly fractured and karstified platy, micritic limestone (Olonos-Pindos Unit) in the footwall. A complete lithologic section is now available through the monitoring of cuttings and cores, which built a major cornerstone for defining an integrated regional tectonic and geologic model. Several pumping tests and hydrochemical investigations made in the region of Aigion and especially in the AIG10 borehole deliver together with geophysical borehole logging the database for a thermo-hydraulic heat flow model. The pumping test AIG10C in the conglomerates of the graben sediments show a hydraulic conductivity of about 2 x 10E-5 m/s - 3 x 10E-4 m/s at a depth of approximately 211 m. The result was a residual drawdown, which indicates a closed hydraulic system between the semi-permeable Aigion fault zone and other faults farther north. The second pumping test AIG10L at 708-750 m depth shows artesian conditions with a fluid pressure of 5 bar and a flow of approx. 40 l/min. The hydraulic conductivity was about 1 x 10E-7 m/s. By drilling deeper an increase of pressure and flux immediately after crossing the fault zone was observed. The cores from 773-786 m depth and the hydraulic behaviour of the deeper intervals up to 1001-m depth suggest karstic water-flow conditions. The water-pressure difference of more than 5 bar between the hanging wall and the footwall provides additional evidence that the Aigion fault zone has a water-blocking capability. An artesian production test showed that the pressure of > 10 bar and the flow of 900 l/min did not decrease for more than four days. An average hydraulic conductivity of 1 x 10E-6 m/s was determined. From this test and the second pumping test we conclude that the Aigion fault zone behaves as a semi-permeable zone or even as a hydraulic barrier not only in the conglomerates but also in the platy limestones.
In drei Horizonten wurde in den Mauerer Sanden nach Kleinsäugerresten gesucht. Zusätzlich zu eine... more In drei Horizonten wurde in den Mauerer Sanden nach Kleinsäugerresten gesucht. Zusätzlich zu einer bisher schon bekannten Waldmaus-Art sowie mehreren Wühlmaus-Arten wurde erst mals die Spitzmaus-Gattung Sorex gefunden. Damit wird die Existenz einer 'Mauerer Waldzeit', in welcher der Homo heidelbergensis lebte, auch durch weitere Kleinsäuger bestätigt.
[On the micromammal fauna in the Middle Pleistoecene 'Mauer Sands']
We searched three horizons of the ' Mauer Sands' for micromammal remnants, In addition to a previously known species of wood mouse as well as several vole species we found the shrew mouse Sorex for the tirst time. Therewith the existence or a warm period named 'Mauer forest time' du ring which Homo heidelbergensis lived is confirmed by additional micro mammals.
Zeitschrift für Geomorphologie, Supplementary Issues, Feb 6, 2014
"Environmental and cultural changes and their mutual relationship or influence have long been a s... more "Environmental and cultural changes and their mutual relationship or influence have long been a subject of research, in particular in the Eastern Mediterranean region with its long historical and prehistorical record. However, especially mainland Greece faces a dearth of environmental records with a comparatively high temporal resolution near archaeological sites. Here we present a 6500 year long record of a sediment core taken in the Asea valley on the central Peloponnese, where an intensive archaeological survey has identified traces of human presence dating back to the Middle/Upper Paleolithic.
Our paleo-environmental reconstruction is based on geochemical analyses of a sediment core by high-resolution XRF scanning in combination with a Bayesian age-depth-model built on 31 AMS-14C dates. After a long period of relatively stable climatic conditions from Late Neolithic into the Late Bronze Age between 6500 and 3500 cal BP (4550 –1550 cal BC), the Asea valley experienced a phase of more humid and potentially also cooler conditions towards the end of the Late Bronze Age until the Middle Geometric period (around 3250 – 2700 cal BP / 1300 –750 cal BC). This was followed by a relatively dry and/or warm period which had its maximum in the Hellenistic period around 2300 cal BP (300 cal BC).
The lack of lake sediments and the formation of soils in the uppermost part of the Asea-1 sedimentary record limit the use of our proxies for reconstructing the environmental history of the last 2000 years. "
Isla de los Estados (54° 45′S, 63° 10′–64° 46′W) lies east of the main island of Tierra del Fuego... more Isla de los Estados (54° 45′S, 63° 10′–64° 46′W) lies east of the main island of Tierra del Fuego and is the southeastern-most point in Argentina. Because of its geographic position near the latitudes of the Southern Hemisphere Westerlies and the strong influence of the Antarctic Circumpolar Current (ACC), the area is suitable for paleoecological and paleoclimate research. The island is not far north of the Subantarctic Front, which limits the northern boundary of the ACC. Paleoenvironmental study in this geographic location can shed light on past changes in atmospheric and marine circulation patterns. Diatom analysis of the lower part of a sediment sequence from Laguna Cascada (54° 45′ 51.3′′S, 64° 20′ 20.07′′W) enabled inference of changing lake conditions between 16 and 11.1 cal ka BP. Between 16 and 14.4 cal ka BP fragilarioid diatom species, often a pioneer group, dominated the record. Their presence shows seasonally open-water conditions from the onset of sedimentation. In zone II (14.4–12.8 cal ka BP), the dominance of planktonic/tychoplanktonic Aulacoseira spp. might represent longer ice-free periods and windier conditions, which would have kept this heavy species suspended in the water column. This period corresponds to the Antarctic Cold Reversal, when the Southern Hemisphere Westerlies were possibly centered on the latitudes of Tierra del Fuego, resulting in windy and wet conditions. Zone III (12.8–11.1 cal ka BP) is dominated by benthic diatom taxa that are mainly associated with peat and wetland vegetation. This suggests that climate conditions had become milder and less windy, favoring aquatic productivity and terrestrial vegetation development. This change in environmental conditions may have been a consequence of the southward movement of the Southern Hemisphere Westerlies at the start of the Antarctic Holocene thermal optimum.
The sedimentary sequence of Lake Stymphalia (NE-Peloponnese) for the first time sheds light on th... more The sedimentary sequence of Lake Stymphalia (NE-Peloponnese) for the first time sheds light on the palaeoclimate development of Southern Greece from 15 to 5 ka BP. New geochemical data based on high-resolution X-ray fluorescence scanning provide in-situ, and continuous analysis of predefined element suites on split-core surfaces. Variations of elements over time were assessed constructing correlation matrices based on the calculation of Pearson correlation coefficients. The element suite includes Al, Si, K, Ca, Ti, Mn, Fe, Zn, Rb, Sr, and Zr. A major result includes that changes in element behaviour are related to hydrological changes in the catchment (precipitation), lake level status, and evaporation (insolation/solar activity), and are ultimately driven by climate.Major trends/shifts in elemental ratios correspond to the climate development in the Eastern Mediterranean region. Based on correlation of Rb/Sr, reflecting wet/dry climates, with foraminiferal proxies of marine core LC21 from the Southern Aegean Sea, and the stable oxygen-isotope record of Soreq cave (Israel), the Bølling–Allerød, the Younger Dryas, and the 8.2 ka cold event were identified.
The question of the origin of Alpine farming and pastoral activities associated with seasonal ver... more The question of the origin of Alpine farming and pastoral activities associated with seasonal vertical transhumance and dairy production in the Silvretta Alps (Eastern Switzerland) has recently benefitted from renewed interest. There, pastoral practises began during the Late Neolithic (2300 BC), but alpine dairy farming was directly evidenced so far only since the Late Bronze Age/Early Iron Age (1300–500 BC). The vegetation development, timberline shifts at 2280 m a.s.l. and environmental conditions of the subalpine Urschai Valley (Canton of Grisons, Switzerland) were reconstructed for the small (8 m2) Plan da Mattun fen based on palynological and geochemical analyses for the last six millennia. The X-ray fluorescence (XRF) analyses are among the first ones performed on a European peatland in such altitudes. A high Rb/Sr ratio in the fen peat sediments revealed an increase in catchment erosion during the time when the forests of the Upper Urschai Valley were steadily diminished probably by fire and livestock impact (2300–1700 BC). These landscape openings were paralleled by increasing micro-charcoal influx values, suggesting that prehistoric people actively set fire on purpose. Simultaneously, palynological evidence for pastoralism was revealed, such as pollen from typical herbs indicating livestock trampling, and abundant spores from coprophilous fungi. Since then, vertical transhumance and pastoral activities remained responsible for the open subalpine landscape above 2000 m a.s.l., most probably also in the context of milk and dairy production since 1300 BC, which is characteristic for the European Alps until today.
A high quantity of well-dated, high-resolution, continuous geoarchives is needed to connect palae... more A high quantity of well-dated, high-resolution, continuous geoarchives is needed to connect palaeoen-vironmental reconstructions with socio-environmental and cultural transformations in a geographi-cally heterogeneous region such as southern Greece. However, detailed and continuous palaeoclimaticand palaeoenvironmental archives from the NE Peloponnese are still sparse. Here, we present two newpalaeolake archives of Pheneos and Kaisari covering the last 10 500 and 6500 years, respectively. Forthe last 5000 years, we compare them with sediment records from adjacent Lake Stymphalia and the Asea valley by applying the same set of sedimentological, geochemical, and statistical analyses to allfour lacustrine archives. Continuous geochemical X-ray fluorescence (XRF) core scanning records provide evidence forhydrological variations and environmental changes since the Early Helladic period (5050 BP), thebeginning of the Bronze Age in Greece. We hereby focus on different spatial scales to estimate thevalidity range of the proxy signals. Ten elements were selected (Al, Si, K, Ca, Ti, Mn, Fe, Rb, Sr,Zr) for a principal component analysis. The clr(Ca/Ti) was chosen as the most meaningful proxy,reflecting varying input of carbonaceous vs. clastic input, which may be linked to changes in the hy-drological conditions. Our results show phases when permanent lake water bodies existed (ca. 5000–3600 cal BP) as well as phases with periodic desiccation of the lakes during younger times. WhilePheneos and Kaisari show a drying trend during the transition phase from the Late Helladic periodto the Proto-Geometric period (ca. 3200–2800 cal BP), Stymphalia and Asea show a rather short drypeak around 3200 cal BP followed by a wetter phase.
This paper aims at reconstructing the palaeoclimatic changes during the last 2600 years in southe... more This paper aims at reconstructing the palaeoclimatic changes during the last 2600 years in southern Greece based on a proxy record from Lake Trichonida. For the first time, we provide a reliable age-depth model and continuous geochemical data for the largest and deepest lake in Greece. We use X-ray fluorescence (XRF) geochemical data supported by discrete mineral analysis based on X-ray diffraction (XRD), grain size distribution, and organic matter content to investigate changes in the lake sedimentary system and identify the major forcing mechanisms. A principal component analysis based on the XRF geochemical composition identifies the variation between carbonate-rich material, precipitating predominantly under drier and/or warmer conditions, and terrigenous sediment input, with it being more prominent during wetter and/or colder conditions. The first principal component (PC1) shows a very strong correlation with the weathering proxy log(Rb/Sr), and we interpret both proxies as depicting fluctuations in the hydrological conditions. A cluster analysis, conducted on the continuous geochemical and colour parameters, highlights the similarities in the sediment charac-teristics deposited during wetter phases, notably during 1850–1750, 1500–1400, ca. 1100, and ca.100 cal BP. ...
Herkules kämpfte an der Karstquelle von Lerna gegen Hydra, ein Wasserungeheuer, wie der Name scho... more Herkules kämpfte an der Karstquelle von Lerna gegen Hydra, ein Wasserungeheuer, wie der Name schon sagt. Im Einzugsgebiet dieser Quelle, dem stymphalischen See, einer Karstpolje mit einem beeindruckenden Schluckloch, befreite er die Bewohner der Gegend von mörderischen Vögeln. Und einen Schritt weiter den Göttern entgegen, auf dem Berg Ziria, dem „Wassersammler“ für den stymphalischen See, befindet sich die Geburtshöhle des Götterboten Hermes, angefüllt mit Tropfsteinen von unglaublicher Schönheit. Die unterschiedlichen Erscheinungsformen des Karst prägen an vielen Stellen die Landschaft des Peloponnes und haben seit jeher die Phantasie der Menschen beflügelt. Der populärwissenschaftliche Artikel führt auf dem Pfad zwischen Phantasie und Forschung auf eine spannende Entdeckungsreise durch die Region.
In this study, we present a modeling approach that investigates how much cultivable land was requ... more In this study, we present a modeling approach that investigates how much cultivable land was required to supply a society and whether societies were in need when environmental conditions deteriorated. The approach is implemented for the NorthEastern Peloponnese and is based upon the location of Late Helladic IIIB (1300-1200 BCE) archaeological sites, an assessment of their sizes, and a proposed diet of the people. Based on these information, the areal requirement of each site is calculated and mapped. The results show that large sites do not have sufficient space in their surroundings in order to supply themselves with the required food resources and thus they depended on supplies from the hinterland. Dry climatic conditions aggravate the situation. This indicates that potential societal crisis are less a factor of changing environmental conditions or a shortage of arable land but primarily caused by socioeconomic factors.
Lacustrine sediments generally record landscape development in the lake's catchment area controll... more Lacustrine sediments generally record landscape development in the lake's catchment area controlled by palaeoclimatic and human induced changes. To improve our understanding on the anthropogenic and climatic influences on landscape development in Southern Greece for the last 2500 years, we report a 2 m-long, continuous high-resolution sedimentary record from shallow Lake Stymphalia (Peloponnese, Greece). Our proxies record climatically as well as anthropogenically induced landscape changes, influencing the lake area and lake depth.
The Classical-Hellenistic era reflects a moderate, stable Mediterranean climate with low sedimentation rates. The parallel existence of the highly populated, major ancient city of Stymphalos, on the contemporary lake edge, doesn't seem to have caused lasting alterations in the record. The construction of the Hadrianic Aqueduct in the Roman era, ca. 130 AD, however causes an influential transformation in the lake development. It has a lasting effect on the lake hydrology as well as the vulnerability of this ecosystem. During Late Roman times, 5th to 6th century cal AD, the abandonment of the aqueduct combined with cooler climate conditions allows lake levels to recover. A phase of very high climatic instability was identified for the subsequent Early Byzantine (EB) period, during the 7th and 8th century cal AD. For this period, the later phase of the Late Antique Little Ice Age (LALIA), our proxies indicate further cooling and highly fluctuating water availability in a rather small lake area. The Middle Byzantine (MB) Period (9th-12th century AD) is characterized by an over fivefold increase in sedimentation rates. Since local population was still well below Classical levels, we explain this singular period through an interaction of modest increase in land use but marked by careless management of deforested areas, warm and wet climatic conditions during the Medieval Warm Period and long-term effects of vulnerability caused by the aqueduct construction. Probably during this phase, the lake level rose through unparalleled sedimentary infill to flood and bury a significant part of the Lower Town of the abandoned ancient city. The Late Byzantine Period (13th and 14th century AD) sees core evidence for erosion of established, non-vegetated soils (high magnetic susceptibility), in a period of almost total depopulation. In the subsequent Ottoman era (late 15th – early 19th centuries AD) local settlement made only slight recovery, the climatic conditions seem less stable during the Little Ice Age (LIA) and the lake seasonally and later periodically starts to dry up, cumulating in a longer dry phase at the end of the 19th century AD, when agricultural activity on the polje floor was possible. The conclusion conforms with recent modelling of environmental change, critical of mono-causation, rather focussing on complex interactions of human and natural factors in the inception of landscape transformation.
In this study, we combine erosion and anthropogenic proxies (Ti, Pb) from calibrated portable XRF... more In this study, we combine erosion and anthropogenic proxies (Ti, Pb) from calibrated portable XRF with pollen and radiocarbon chronologies in peat from mires of the Kleinwalser Valley (Kleinwalsertal, Vorarlberg, Austria) to reconstruct palaeoenvironmental change and human impact in the northern central Alps. Favoured by a wetter climate, two analysed mires formed 6200 years ago in a densely forested valley. Landscape opening suggests that the first anthropogenic impact emerged around 5700 to 5300 cal BP. Contemporaneously, lead enrichment factors (Pb EFs) indicate metallurgical activities, predating the earliest archaeological evidence in the region. Pollen and erosion proxies show that large-scale deforestation and land use by agro-pastoralists took place from the mid- to late Bronze Age (3500 to 2800 cal BP). This period was directly followed by a prominent peak in Pb EF, pointing to metallurgical activities again. After 200 cal CE, a rising human impact was interrupted by climatic deteriorations in the first half of the 6th century CE, probably linked to the Late Antique Little Ice Age. The use of the characteristic Pb EF pattern of modern pollution as a time marker allows us to draw conclusions about the last centuries. These saw the influence of the Walser people, arriving in the valley after 1300 cal CE. Later, the beginning of tourism is reflected in increased erosion signals after 1950 cal CE. Our study demonstrates that prehistoric humans were intensively shaping the Kleinwalser Valley's landscape, well before the arrival of the Walser people. It also demonstrates the importance of palaeoenvironmental multiproxy studies to fill knowledge gaps where archaeological evidence is lacking.
Thermokarst lakes cover nearly one fourth of ice-rich permafrost lowlands in the Arctic. Sediment... more Thermokarst lakes cover nearly one fourth of ice-rich permafrost lowlands in the Arctic. Sediments from an athalassic subsaline thermokarst lake on Herschel Island (69°36′N; 139°04′W, Canadian Arctic) were used to understand regional changes in climate and in sediment transport, hydrology, nutrient availability and permafrost disturbance. The sediment record spans the last ~ 11,700 years and the basal date is in good agreement with the Holocene onset of thermokarst initiation in the region. Electrical conductivity in pore water continuously decreases, thus indicating desalinization and continuous increase of lake size and water level. The inc/coh ratio of XRF scans provides a high-resolution organic-carbon proxy which correlates with TOC measurements. XRF-derived Mn/Fe ratios indicate aerobic versus anaerobic conditions which moderate the preservation potential of organic matter in lake sediments. The coexistence of marine, brackish and freshwater ostracods and foraminifera is explained by (1) oligohaline to mesohaline water chemistry of the past lake and (2) redeposition of Pleistocene specimens found within upthrusted marine sediments around the lake. Episodes of catchment disturbance are identified when calcareous fossils and allochthonous material were transported into the lake by thermokarst processes such as active-layer detachments, slumping and erosion of ice-rich shores. The pollen record does not show major variations and the pollen-based climate record does not match well with other summer air temperature reconstructions from this region. Local vegetation patterns in small catchments are strongly linked to morphology and sub-surface permafrost conditions rather than to climate. Multidisciplinary studies can identify the onset and life cycle of thermokarst lakes as they play a crucial role in Arctic freshwater ecosystems and in the global carbon cycle of the past, present and future.
Fossils represent invaluable data to reconstruct the past history of life, yet fossil-rich sites ... more Fossils represent invaluable data to reconstruct the past history of life, yet fossil-rich sites are often rare and difficult to find. The traditional fossil-hunting approach focuses on small areas and has not yet taken advantage of modelling techniques commonly used in ecology to account for an organism's past distributions. We propose a new method to assist finding fossils at continental scales based on modelling the past distribution of species, the geological suitability of fossil preservation and the likelihood of fossil discovery in the field, and apply it to several genera of Australian megafauna that went extinct in the Late Quaternary. Our models predicted higher fossil potentials for independent sites than for randomly selected locations (mean Kolmogorov-Smirnov statistic = 0.66). We demonstrate the utility of accounting for the distribution history of fossil taxa when trying to find the most suitable areas to look for fossils. For some genera, the probability of finding fossils based on simple climate-envelope models was higher than the probability based on models incorporating current conditions associated with fossil preservation and discovery as predictors. However , combining the outputs from climate-envelope, preservation, and discovery models resulted in the most accurate predictions of potential fossil sites at a continental scale. We proposed potential areas to discover new fossils of Diprotodon, Zygomaturus, Protemno-don, Thylacoleo, and Genyornis, and provide guidelines on how to apply our approach to assist fossil hunting in other continents and geological settings.
Special Issue: Mediterranean Holocene Climate, Environment and Human Societies, Mar 15, 2016
Published archaeological, palaeoenvironmental, and palaeoclimatic data from the Peloponnese in Gr... more Published archaeological, palaeoenvironmental, and palaeoclimatic data from the Peloponnese in Greece are compiled, discussed and evaluated in order to analyse the interactions between humans and the environment over the last 9000 years. Our study indicates that the number of human settlements found scattered over the peninsula have quadrupled from the prehistoric to historical periods and that this evolution occurred over periods of climate change and seismo–tectonic activity. We show that societal development occurs both during periods of harsh as well as favourable climatic conditions. At some times, some settlements develop while others decline. Well-known climate events such as the 4.2 ka and 3.2 ka events are recognizable in some of the palaeoclimatic records and a regional decline in the number and sizes of settlements occurs roughly at the same time, but their precise chronological fit with the archaeological record remains uncertain. Local socio-political processes were probably always the key drivers behind the diverse strategies that human societies took in times of changing climate. The study thus reveals considerable chronological parallels between societal development and palaeoenvironmental records, but also demonstrates the ambiguities in these correspondences and, in doing so, highlights some of the challenges that will face future interdisciplinary projects. We suggest that there can be no general association made between societal expansion phases and periods of advantageous climate. We also propose that the relevance of climatic and environmental regionality, as well as any potential impacts of seismo-tectonics on societal development, need to be part of the interpretative frameworks.
A well-dated palynological record spanning the interval ~ 40,500–7060 cal yr BP, retrieved from a... more A well-dated palynological record spanning the interval ~ 40,500–7060 cal yr BP, retrieved from a peatland on the Leizhou Peninsula in south China, clearly shows regional vegetation and climate changes during the last glacial period. Pollen data showed that the study region was mainly covered by subtropical evergreen trees during Marine Isotope Stage 3 (MIS 3), indicating a subtropical climate with relatively high temperature and precipitation. During MIS 2, subtropical evergreen-deciduous forest with large areas of grassland occurred, implying cooler and drier conditions. Some tropical forest elements increased during the early Holocene, indicating a warm and wet trend. Several millennial-scale oscillations of the pollen records appeared to correlate with the cold anomalies in the North Atlantic region. Our records agree well with many records from other regions, but they are a bit different than that inferred from the neighboring Huguang Maar Lake. Furthermore, our results suggest that the vegetation surrounding Xialu peatland was strongly influenced by the migration of the intertropical convergence zone (ITCZ) and variability in the East Asian summer monsoon (EASM). Changes of atmospheric CO2 concentration (pCO2) levels may have also affected the long-term vegetation changes in the study region
Here, we present a well-dated terrestrial charcoal chronology covering the interval ~ 41,000–7050... more Here, we present a well-dated terrestrial charcoal chronology covering the interval ~ 41,000–7050 cal BP and identifying the millennial-scale variability in biomass burning for the tropical Leizhou Peninsula, south China. Our results show that changes in biomass burning closely followed regional temperature and precipitation variations on orbital timescales, i.e., more biomass burning occurred during the warm/wet Marine Isotope Stage (MIS) 3, and less biomass burning occurred during the cold/dry MIS 2. Superimposed on this general trend, our charcoal record shows millennial-scale variability in biomass burning corresponding to the rapid climate changes associated with Dansgaard–Oeschger (D–O) cycles, i.e., biomass burning increased during D–O warming events, whereas biomass burning decreased during intervals of rapid cooling terminated by Heinrich events. During the cooler/drier periods, low biomass burning can be explained by the decline of vegetation productivity, whereas the warmer/wetter periods are characterized by higher biomass burning related to increasing fuel availability. Therefore, climate control can be considered as the major forcing factor of biomass burning from 41,000–7050 cal BP on both orbital and millennial timescales in the northern Leizhou Peninsula.
As part of the lagoon barrier accretions plain characterizing the NW coast of the Peloponnese, th... more As part of the lagoon barrier accretions plain characterizing the NW coast of the Peloponnese, the Kotychi Lagoon is believed to
have formed in the prograding delta of the Palaeo-Peneus River over 7000 years ago. Geochemical/sedimentological proxies-data
(XRF, grain size, OC-, IC-, C/N-analysis) combined with Bayesian age-depth-modeling revealed that from 8500 to 8000 cal BP
marine conditions were prevailing. Around 8000 cal BP, a short-lived sequence of coastline progradation and barrier accretion
created lagoonal conditions. Thus, the first chronological control for the onset of lagoon formation in coastal Elis is presented.
Pronounced lagoonal conditions developed approximately 6300 cal BP, simultaneously to the period of circum-Mediterranean
lagoon formation. A rapidly varying sedimentary record indicates a phase of geomorphological instability between 5200 and 3500
cal BP terminating with the erosional unconformity of a river channel. This evolution reflects a two-phase development: (1) Early
Holocene morphology was controlled by the postglacial sea level rise; (2) with receding of the ice sheets by mid-Holocene, the
preeminent role of the eustatic signal was overwhelmed giving local and regional processes, such as human-induced soil erosion
and climatic forcing an accentuated role. Thus, the evolution of the Elean coastline shows analogies to circum-Mediterranean
lagoon formation.
Before the arrival of the Spaniards in Peru in 1532, many different societies flourished in the c... more Before the arrival of the Spaniards in Peru in 1532, many different societies flourished in the coastal desert of southern Peru. Of these, one of the best known is the Nasca culture (living in the area between about 260 cal BC and 640 cal BC.), which created the famous geoglyphs on the desert floor. In this paper we present a numerical chronology for the cultural development in the valleys of Palpa, in the northern part of the Nazca region, which spans the time from the Archaic Period (starting there around 3760 cal BC) to the Late Intermediate Period (terminating with the arrival of the Spaniards in 1532 AD). The chronology is based on more than 150 14C samples collected by our project from well-documented archaeological excavations of 17 different sites in and around Palpa. Thanks to the advanced AMS-14C dating technique, demanding only few milligrams of organic material, we could focus on samples of plants, like beans, corn, or reed, representing single years of growth or use, and also on delicate materials like straw from clay bricks (adobe) and textiles. All single 14C dates were combined to cultural phases using a Bayesian statistical model, implementing the a priori information of the archaeological contexts, and adopting the relative ceramic chronologies available for this area.► We present a numerical chronology for the cultural development in the valleys of Palpa (South Peru). ► More than 150 radiocarbon dates and archaeological age information are combined in a Bayesian model. ► The chronology covers the time from 3720 cal BC (start Archaic Period) to 1532 cal AD (end Late Intermediate Period).
The Gulf of Corinth and the northern part of the Peloponnesus/Greece, an area of asymmetric grabe... more The Gulf of Corinth and the northern part of the Peloponnesus/Greece, an area of asymmetric graben structure, step faults and tilted blocks, is one of the most active seismic zones in the world. Six major faults are known to be most responsible for the historic and present seismic activities in the area of Aigion. Our study focuses preliminarily on the area around the Aigion fault, whose trace runs E-W through the harbour of Aigion. Investigations of the stratigraphic sequence, tectonic structure and hydrogeologic conditions of the southern Corinth graben shoulder and first drilling activities there, have started in summer 2001. From July until September 2002 the International Continental Deep Drilling Project (ICDP) and the EU Project DGLab-Gulf of Corinth drilled the AIG10 borehole in the harbour of Aigion to a total depth of 1001 m. Our investigations in this ICDP/EU framework are aimed at studying the thermal-hydraulic conditions on the southern graben shoulder. Here we report the first results on sampling and hydraulic testing. The deep AIG10 borehole has successfully cored in approx. 760 m depth the fault plane, which separates fractured radiolarite in the hanging wall from highly fractured and karstified platy, micritic limestone (Olonos-Pindos Unit) in the footwall. A complete lithologic section is now available through the monitoring of cuttings and cores, which built a major cornerstone for defining an integrated regional tectonic and geologic model. Several pumping tests and hydrochemical investigations made in the region of Aigion and especially in the AIG10 borehole deliver together with geophysical borehole logging the database for a thermo-hydraulic heat flow model. The pumping test AIG10C in the conglomerates of the graben sediments show a hydraulic conductivity of about 2 x 10E-5 m/s - 3 x 10E-4 m/s at a depth of approximately 211 m. The result was a residual drawdown, which indicates a closed hydraulic system between the semi-permeable Aigion fault zone and other faults farther north. The second pumping test AIG10L at 708-750 m depth shows artesian conditions with a fluid pressure of 5 bar and a flow of approx. 40 l/min. The hydraulic conductivity was about 1 x 10E-7 m/s. By drilling deeper an increase of pressure and flux immediately after crossing the fault zone was observed. The cores from 773-786 m depth and the hydraulic behaviour of the deeper intervals up to 1001-m depth suggest karstic water-flow conditions. The water-pressure difference of more than 5 bar between the hanging wall and the footwall provides additional evidence that the Aigion fault zone has a water-blocking capability. An artesian production test showed that the pressure of > 10 bar and the flow of 900 l/min did not decrease for more than four days. An average hydraulic conductivity of 1 x 10E-6 m/s was determined. From this test and the second pumping test we conclude that the Aigion fault zone behaves as a semi-permeable zone or even as a hydraulic barrier not only in the conglomerates but also in the platy limestones.
In drei Horizonten wurde in den Mauerer Sanden nach Kleinsäugerresten gesucht. Zusätzlich zu eine... more In drei Horizonten wurde in den Mauerer Sanden nach Kleinsäugerresten gesucht. Zusätzlich zu einer bisher schon bekannten Waldmaus-Art sowie mehreren Wühlmaus-Arten wurde erst mals die Spitzmaus-Gattung Sorex gefunden. Damit wird die Existenz einer 'Mauerer Waldzeit', in welcher der Homo heidelbergensis lebte, auch durch weitere Kleinsäuger bestätigt.
[On the micromammal fauna in the Middle Pleistoecene 'Mauer Sands']
We searched three horizons of the ' Mauer Sands' for micromammal remnants, In addition to a previously known species of wood mouse as well as several vole species we found the shrew mouse Sorex for the tirst time. Therewith the existence or a warm period named 'Mauer forest time' du ring which Homo heidelbergensis lived is confirmed by additional micro mammals.
Zeitschrift für Geomorphologie, Supplementary Issues, Feb 6, 2014
"Environmental and cultural changes and their mutual relationship or influence have long been a s... more "Environmental and cultural changes and their mutual relationship or influence have long been a subject of research, in particular in the Eastern Mediterranean region with its long historical and prehistorical record. However, especially mainland Greece faces a dearth of environmental records with a comparatively high temporal resolution near archaeological sites. Here we present a 6500 year long record of a sediment core taken in the Asea valley on the central Peloponnese, where an intensive archaeological survey has identified traces of human presence dating back to the Middle/Upper Paleolithic.
Our paleo-environmental reconstruction is based on geochemical analyses of a sediment core by high-resolution XRF scanning in combination with a Bayesian age-depth-model built on 31 AMS-14C dates. After a long period of relatively stable climatic conditions from Late Neolithic into the Late Bronze Age between 6500 and 3500 cal BP (4550 –1550 cal BC), the Asea valley experienced a phase of more humid and potentially also cooler conditions towards the end of the Late Bronze Age until the Middle Geometric period (around 3250 – 2700 cal BP / 1300 –750 cal BC). This was followed by a relatively dry and/or warm period which had its maximum in the Hellenistic period around 2300 cal BP (300 cal BC).
The lack of lake sediments and the formation of soils in the uppermost part of the Asea-1 sedimentary record limit the use of our proxies for reconstructing the environmental history of the last 2000 years. "
Isla de los Estados (54° 45′S, 63° 10′–64° 46′W) lies east of the main island of Tierra del Fuego... more Isla de los Estados (54° 45′S, 63° 10′–64° 46′W) lies east of the main island of Tierra del Fuego and is the southeastern-most point in Argentina. Because of its geographic position near the latitudes of the Southern Hemisphere Westerlies and the strong influence of the Antarctic Circumpolar Current (ACC), the area is suitable for paleoecological and paleoclimate research. The island is not far north of the Subantarctic Front, which limits the northern boundary of the ACC. Paleoenvironmental study in this geographic location can shed light on past changes in atmospheric and marine circulation patterns. Diatom analysis of the lower part of a sediment sequence from Laguna Cascada (54° 45′ 51.3′′S, 64° 20′ 20.07′′W) enabled inference of changing lake conditions between 16 and 11.1 cal ka BP. Between 16 and 14.4 cal ka BP fragilarioid diatom species, often a pioneer group, dominated the record. Their presence shows seasonally open-water conditions from the onset of sedimentation. In zone II (14.4–12.8 cal ka BP), the dominance of planktonic/tychoplanktonic Aulacoseira spp. might represent longer ice-free periods and windier conditions, which would have kept this heavy species suspended in the water column. This period corresponds to the Antarctic Cold Reversal, when the Southern Hemisphere Westerlies were possibly centered on the latitudes of Tierra del Fuego, resulting in windy and wet conditions. Zone III (12.8–11.1 cal ka BP) is dominated by benthic diatom taxa that are mainly associated with peat and wetland vegetation. This suggests that climate conditions had become milder and less windy, favoring aquatic productivity and terrestrial vegetation development. This change in environmental conditions may have been a consequence of the southward movement of the Southern Hemisphere Westerlies at the start of the Antarctic Holocene thermal optimum.
The sedimentary sequence of Lake Stymphalia (NE-Peloponnese) for the first time sheds light on th... more The sedimentary sequence of Lake Stymphalia (NE-Peloponnese) for the first time sheds light on the palaeoclimate development of Southern Greece from 15 to 5 ka BP. New geochemical data based on high-resolution X-ray fluorescence scanning provide in-situ, and continuous analysis of predefined element suites on split-core surfaces. Variations of elements over time were assessed constructing correlation matrices based on the calculation of Pearson correlation coefficients. The element suite includes Al, Si, K, Ca, Ti, Mn, Fe, Zn, Rb, Sr, and Zr. A major result includes that changes in element behaviour are related to hydrological changes in the catchment (precipitation), lake level status, and evaporation (insolation/solar activity), and are ultimately driven by climate.Major trends/shifts in elemental ratios correspond to the climate development in the Eastern Mediterranean region. Based on correlation of Rb/Sr, reflecting wet/dry climates, with foraminiferal proxies of marine core LC21 from the Southern Aegean Sea, and the stable oxygen-isotope record of Soreq cave (Israel), the Bølling–Allerød, the Younger Dryas, and the 8.2 ka cold event were identified.
The conference is a collaborative effort among members of the PELOPS (Past Environments and Lands... more The conference is a collaborative effort among members of the PELOPS (Past Environments and Landscapes of Peloponnesian Societies) group, which is an interdisciplinary group of scholars with an ongoing engagement in human-environment interaction in the Peloponnese from archaeology, history, environmental and climate reconstructions.
The primary aim of the conference is to make a contribution to the ongoing debate concerning the form and content of interdisciplinary research on human-environment dynamics in past societies from prehistory to Late Antiquity. The conference will be an arena for innovative ideas, integrated methods and lessons learnt from current interdisciplinary projects in the Peloponnese and beyond. In answer to the open call for more collaborative research efforts, the conference will host 17 lectures by members of the PELOPS group and invited speakers, presenting well integrated accounts of human-environment interactions in past societies.
The conference will open on Thursday, 6 April, 2017, 7 pm at the Acropolis museum, with a lecture by Michael GIVEN (University of Glasgow), ‘Conviviality of the land: towards a new academic ecology’, followed by a welcome reception at the Swedish Institute at Athens.
The conference will thereafter take place at the American School of Classical Studies at Athens, 7-8 April, 9 am-18 pm.
Past Landscapes. The Dynamics of Interaction between Society, Landscape and Culture, 2019
Environmental and cultural changes and their mutual relationship or influence have been a subject... more Environmental and cultural changes and their mutual relationship or influence have been a subject of extensive research in the Eastern Mediterranean region with its long historical and prehistorical record. Focussing on Greece, the potential impact of the so-called 4.2 ka climate event (around 2200 BC) on the cultural shift from the Early Helladic II to the Early Helladic III period, or the role of the 2.7 ka climate event around (around 750 BC) on the Bronze Age / Iron Age transition were and still are hot topics of transdisciplinary research. However, the determination of factors of forcing and response in the human-environment-interplay in that region is especially challenging, as Southern Greece faces a dearth of environmental records with a comparatively high temporal resolution which are sufficiently close to archaeological sites. In the Peloponnese, Lake Stymphalia is the only natural lake remaining today. It is located in the direct vicinity of well-known archaeological sites such as Mycene or Corinth. Settlement activity in the Valley of Stymphalia itself is known from at least the 5th century BC and is specified by Pausanias in his “Description of Greece” (ca. 160–175 AD). Hence, the lake provides an excellent archive for environmental studies in an archaeological context. To reconstruct archaeohydrological and palaeoenvironmental changes over the last 5000 years, covering the cultural periods of Greece until the Early Bronze Age (Early Helladic I), sediment cores were retrieved from the lake and geochemically analysed. First results indicate a rather limited contribution of climate to the transition from the Late Bronze Age to the Early Iron Age (ca. 1300–900 BC), while a more significant cold event recorded in the area seems to coincide with the Late Antiquity Little Ice Age in the 6th and 7th century AD. Beyond the questions on the impact of climate on the changing availability of water, ancient prose and poetry text sources dealing with Stymphalos yield interesting information on how the people of different cultural periods managed the water resources and how they perceived and reflected on different hydrological phenomena.
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Papers by Ingmar Unkel
The Classical-Hellenistic era reflects a moderate, stable Mediterranean climate with low sedimentation rates. The parallel existence of the highly populated, major ancient city of Stymphalos, on the contemporary lake edge, doesn't seem to have caused lasting alterations in the record. The construction of the Hadrianic Aqueduct in the Roman era, ca. 130 AD, however causes an influential transformation in the lake development. It has a lasting effect on the lake hydrology as well as the vulnerability of this ecosystem. During Late Roman times, 5th to 6th century cal AD, the abandonment of the aqueduct combined with cooler climate conditions allows lake levels to recover. A phase of very high climatic instability was identified for the subsequent Early Byzantine (EB) period, during the 7th and 8th century cal AD. For this period, the later phase of the Late Antique Little Ice Age (LALIA), our proxies indicate further cooling and highly fluctuating water availability in a rather small lake area. The Middle Byzantine (MB) Period (9th-12th century AD) is characterized by an over fivefold increase in sedimentation rates. Since local population was still well below Classical levels, we explain this singular period through an interaction of modest increase in land use but marked by careless management of deforested areas, warm and wet climatic conditions during the Medieval Warm Period and long-term effects of vulnerability caused by the aqueduct construction. Probably during this phase, the lake level rose through unparalleled sedimentary infill to flood and bury a significant part of the Lower Town of the abandoned ancient city. The Late Byzantine Period (13th and 14th century AD) sees core evidence for erosion of established, non-vegetated soils (high magnetic susceptibility), in a period of almost total depopulation. In the subsequent Ottoman era (late 15th – early 19th centuries AD) local settlement made only slight recovery, the climatic conditions seem less stable during the Little Ice Age (LIA) and the lake seasonally and later periodically starts to dry up, cumulating in a longer dry phase at the end of the 19th century AD, when agricultural activity on the polje floor was possible. The conclusion conforms with recent modelling of environmental change, critical of mono-causation, rather focussing on complex interactions of human and natural factors in the inception of landscape transformation.
This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
have formed in the prograding delta of the Palaeo-Peneus River over 7000 years ago. Geochemical/sedimentological proxies-data
(XRF, grain size, OC-, IC-, C/N-analysis) combined with Bayesian age-depth-modeling revealed that from 8500 to 8000 cal BP
marine conditions were prevailing. Around 8000 cal BP, a short-lived sequence of coastline progradation and barrier accretion
created lagoonal conditions. Thus, the first chronological control for the onset of lagoon formation in coastal Elis is presented.
Pronounced lagoonal conditions developed approximately 6300 cal BP, simultaneously to the period of circum-Mediterranean
lagoon formation. A rapidly varying sedimentary record indicates a phase of geomorphological instability between 5200 and 3500
cal BP terminating with the erosional unconformity of a river channel. This evolution reflects a two-phase development: (1) Early
Holocene morphology was controlled by the postglacial sea level rise; (2) with receding of the ice sheets by mid-Holocene, the
preeminent role of the eustatic signal was overwhelmed giving local and regional processes, such as human-induced soil erosion
and climatic forcing an accentuated role. Thus, the evolution of the Elean coastline shows analogies to circum-Mediterranean
lagoon formation.
[On the micromammal fauna in the Middle Pleistoecene 'Mauer Sands']
We searched three horizons of the ' Mauer Sands' for micromammal remnants, In addition to a previously known species of wood mouse as well as several vole species we found the shrew mouse Sorex for the tirst time. Therewith the existence or a warm period named 'Mauer forest time' du ring which Homo heidelbergensis lived is confirmed by additional micro mammals.
Our paleo-environmental reconstruction is based on geochemical analyses of a sediment core by high-resolution XRF scanning in combination with a Bayesian age-depth-model built on 31 AMS-14C dates. After a long period of relatively stable climatic conditions from Late Neolithic into the Late Bronze Age between 6500 and 3500 cal BP (4550 –1550 cal BC), the Asea valley experienced a phase of more humid and potentially also cooler conditions towards the end of the Late Bronze Age until the Middle Geometric period (around 3250 – 2700 cal BP / 1300 –750 cal BC). This was followed by a relatively dry and/or warm period which had its maximum in the Hellenistic period around 2300 cal BP (300 cal BC).
The lack of lake sediments and the formation of soils in the uppermost part of the Asea-1 sedimentary record limit the use of our proxies for reconstructing the environmental history of the last 2000 years. "
The Classical-Hellenistic era reflects a moderate, stable Mediterranean climate with low sedimentation rates. The parallel existence of the highly populated, major ancient city of Stymphalos, on the contemporary lake edge, doesn't seem to have caused lasting alterations in the record. The construction of the Hadrianic Aqueduct in the Roman era, ca. 130 AD, however causes an influential transformation in the lake development. It has a lasting effect on the lake hydrology as well as the vulnerability of this ecosystem. During Late Roman times, 5th to 6th century cal AD, the abandonment of the aqueduct combined with cooler climate conditions allows lake levels to recover. A phase of very high climatic instability was identified for the subsequent Early Byzantine (EB) period, during the 7th and 8th century cal AD. For this period, the later phase of the Late Antique Little Ice Age (LALIA), our proxies indicate further cooling and highly fluctuating water availability in a rather small lake area. The Middle Byzantine (MB) Period (9th-12th century AD) is characterized by an over fivefold increase in sedimentation rates. Since local population was still well below Classical levels, we explain this singular period through an interaction of modest increase in land use but marked by careless management of deforested areas, warm and wet climatic conditions during the Medieval Warm Period and long-term effects of vulnerability caused by the aqueduct construction. Probably during this phase, the lake level rose through unparalleled sedimentary infill to flood and bury a significant part of the Lower Town of the abandoned ancient city. The Late Byzantine Period (13th and 14th century AD) sees core evidence for erosion of established, non-vegetated soils (high magnetic susceptibility), in a period of almost total depopulation. In the subsequent Ottoman era (late 15th – early 19th centuries AD) local settlement made only slight recovery, the climatic conditions seem less stable during the Little Ice Age (LIA) and the lake seasonally and later periodically starts to dry up, cumulating in a longer dry phase at the end of the 19th century AD, when agricultural activity on the polje floor was possible. The conclusion conforms with recent modelling of environmental change, critical of mono-causation, rather focussing on complex interactions of human and natural factors in the inception of landscape transformation.
This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
have formed in the prograding delta of the Palaeo-Peneus River over 7000 years ago. Geochemical/sedimentological proxies-data
(XRF, grain size, OC-, IC-, C/N-analysis) combined with Bayesian age-depth-modeling revealed that from 8500 to 8000 cal BP
marine conditions were prevailing. Around 8000 cal BP, a short-lived sequence of coastline progradation and barrier accretion
created lagoonal conditions. Thus, the first chronological control for the onset of lagoon formation in coastal Elis is presented.
Pronounced lagoonal conditions developed approximately 6300 cal BP, simultaneously to the period of circum-Mediterranean
lagoon formation. A rapidly varying sedimentary record indicates a phase of geomorphological instability between 5200 and 3500
cal BP terminating with the erosional unconformity of a river channel. This evolution reflects a two-phase development: (1) Early
Holocene morphology was controlled by the postglacial sea level rise; (2) with receding of the ice sheets by mid-Holocene, the
preeminent role of the eustatic signal was overwhelmed giving local and regional processes, such as human-induced soil erosion
and climatic forcing an accentuated role. Thus, the evolution of the Elean coastline shows analogies to circum-Mediterranean
lagoon formation.
[On the micromammal fauna in the Middle Pleistoecene 'Mauer Sands']
We searched three horizons of the ' Mauer Sands' for micromammal remnants, In addition to a previously known species of wood mouse as well as several vole species we found the shrew mouse Sorex for the tirst time. Therewith the existence or a warm period named 'Mauer forest time' du ring which Homo heidelbergensis lived is confirmed by additional micro mammals.
Our paleo-environmental reconstruction is based on geochemical analyses of a sediment core by high-resolution XRF scanning in combination with a Bayesian age-depth-model built on 31 AMS-14C dates. After a long period of relatively stable climatic conditions from Late Neolithic into the Late Bronze Age between 6500 and 3500 cal BP (4550 –1550 cal BC), the Asea valley experienced a phase of more humid and potentially also cooler conditions towards the end of the Late Bronze Age until the Middle Geometric period (around 3250 – 2700 cal BP / 1300 –750 cal BC). This was followed by a relatively dry and/or warm period which had its maximum in the Hellenistic period around 2300 cal BP (300 cal BC).
The lack of lake sediments and the formation of soils in the uppermost part of the Asea-1 sedimentary record limit the use of our proxies for reconstructing the environmental history of the last 2000 years. "
The primary aim of the conference is to make a contribution to the ongoing debate concerning the form and content of interdisciplinary research on human-environment dynamics in past societies from prehistory to Late Antiquity. The conference will be an arena for innovative ideas, integrated methods and lessons learnt from current interdisciplinary projects in the Peloponnese and beyond. In answer to the open call for more collaborative research efforts, the conference will host 17 lectures by members of the PELOPS group and invited speakers, presenting well integrated accounts of human-environment interactions in past societies.
The conference will open on Thursday, 6 April, 2017, 7 pm at the Acropolis museum, with a lecture by Michael GIVEN (University of Glasgow), ‘Conviviality of the land: towards a new academic ecology’, followed by a welcome reception at the Swedish Institute at Athens.
The conference will thereafter take place at the American School of Classical Studies at Athens, 7-8 April, 9 am-18 pm.