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Radiocarbon dating of organic-rich deposits: Difficulties of paleogeographical interpretations in highlands of Russian Altai

Nepop R.K., Agatova A.R., Bronnikova M.A., Zazovskaya E.P., Ovchinnikov I.YU., Moska P.

Geochronometria

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2020

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Vol. 47, no.1

138--153

EN

The high mountainous southeastern part of Russian Altai is characterized by complicated sedimentation history. As a result of tectonic movements, Paleogene, Neogene, and even more old Carboniferous and Jurassic organicrich deposits had been partly uplifted and exhumed on the ridge’s slopes, where during the Pleistocene, they were affected by various exogenous processes including glaciation, glacio-fluvial erosion, winnowing activity of ice-dammed lakes, sliding during lake-draining events, followed by further intensive Holocene erosion, pedogenesis, and permafrost formation/degradation. Remobilized ancient organic matter had been involved into geomorphic and pedogenesis processes and affected the results of radiocarbon dating. Numerous radiocarbon ages obtained revealed several typical problems in interpretation of dating results, which was confirmed by multidisciplinary investigations of associated sediments in a wider regional context. This article presents a discussion on obtained apparent radiocarbon dates of organic material from ten sections of the SE Altai. In addition to radiocarbon analysis, in each case multidisciplinary study was carried out in order to properly interpret obtained dates, as well as to explain the inability of directly using apparent 14C ages as a geochronological basis for paleogeographical reconstruction. The analysis presented is of vital importance for establishing the chronology of formation of large ice-dammed lakes and their cataclysmic draining; revealing chronology and paleoenvironmental conditions of pedogenesis in the highlands of the SE Altai; and estimating the range and magnitude of the tectonically driven topography rebuilding in the post-Neogene time.

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14C dating of mortar from ruins of an early medieval church Hohenrätien GR, Switzerland

Hajdas Irka, Maurer Mantana, Röttig Maria Belen

Geochronometria

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2020

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Vol. 47, no.1

118--123

EN

Numerous ruins around the world lack the radiometric dating due to the scarcity of organic carbon. Here, we present results of radiocarbon dating of mortar samples from an early Medieval church Hohenrätien GR, Switzerland, which was dated to the early 6th century, based on typology. The method of dating mortars, which is currently applied at the ETH laboratory, involves sieving the crushed mortar, selection of grain size 45−63 µm and sequential dissolution resulting in four fractions of CO2 collected in a 3-second interval each. Two mortar samples, which were analyzed using sequential dissolution and one by dating a bulk of lime lump, resulted in a combined radiocarbon age of 1551±21 BP translating to the calendar age of 427−559 AD.

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Origin and evolution of basins in the eastern part of Jasło-Sanok Depression (Polish Carpathians) in the Late Vistulian and Holocene

Gerlach Tadeusz, Gębica Piotr, Szczepanek Kazimierz, Nalepka Dorota, Walanus Adam

Studia Quaternaria

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2019

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Vol. 36, Nr 2

171--194

EN

Results of a geomorphologic study as well as radiocarbon and pollen analyses of sediments in small basins of the Jasło-Sanok Depression (Western Carpathians) are summarised. Floors of these basins, carved in soft shale-sandstone Krosno Beds, are covered with channel fluvial deposits and oxbow-lake sediments with lake chalk and peat accumulated in the Late Vistulian and Holocene. Since the early Atlantic Phase (ca 8,400–7,900 BP) the apparent acceleration of overbank (flood) deposition intermitting the peat accumulation is observed. The plant succession includes the Late Glacial (pre-Allerød, Allerød and Younger Dryas) with coniferous park forests, through mixed deciduous forests of the Holocene with elm, hazel, oak and lime as well as spruce-elm forests with alder in wetlands, up to present-day hornbeam forests (Tilio-Carpinetum of various types) and extra-zonal Carpathian beech forests (Dentario-Glandulosae-Fagetum). Abies alba (fir) is frequent in both these association types. First evidences of synanthropic plants that prove presence of prehistoric man appeared in the Subboreal Phase. The oldest radiocarbon date 13,550±100 BP (Gd-7355) [16,710–16,085 b2k], from a bottom part of the Humniska section is probably overestimated. This is indicated by palynological data, which suggest attribution of this section to the older Allerød. Small thickness of gravel blanket from the Plenivistulian termination and the beginning of the Late Vistulian, as well as large areas devoid of weathering and solifluction covers indicate that during the Plenivistulian weathering processes and removal of silt-clay material predominated in the basins. In that time the deflation was among important processes, which is proved by deflation troughs, faceted cobbles and thick covers of the Carpathian type of loess. The Besko Basin has pre-Vistulian tectonic foundation, while landforms of its floor are of erosion-degradation origin and formed during the last Scandinavian glaciation. In the Holocene the basin floors were overbuilt with fluvial deposits up to 8 m thick.

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Późnoglacjalny rozwój osuwisk w polskich Karpatach zewnętrznych

Wójcik Antoni

Przegląd Geologiczny

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2019

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Vol. 67, nr 5

397--404

EN

The area of Poland, including the Carpathian Mountains, is located in a zone where landslides cause large material damage. This issue can be considered using different time scales. Using various dating methods, it was possible to distinguish periods of increased landslide activity. Among others, the radiometric methods are the most common. Based on the 14C dated landslides in Szczawnica-Biafy Stream, Zapadle near Szymbark, Rychwatd near Żywiec and on data published by Margielewski (2006), it was possible to hypothesize that landslides in the Carpathians have been developing over 13,000 years, i.e. since the Oldest Dryas. This is related to the beginning of degradation of the permafrost, which can be considered as the inception of the development of large rock landslides. On the basis of the presented data, it can also be stated that these landslides have been active up to modern times and their development is very long. An example of this is the landslide in Zapadle. The position of the landslide tongue, which is subjected to erosion, is of great importance, which promotes its further activity. Permanent removing of the colluvial material by a stream and its supplementing by subsequent new displacements from the scarp causes that the landslides can be active for a very long period of time.

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Natural Isotopes and Ion Compositions Identify Changes in Groundwater Flows Affecting Wetland Vegetation in the Drentsche Aa Brook Valley, The Netherlands

Elshehawi Samer, Bregman Enno, Schot Paul, Grootjans Ab

Journal of Ecological Engineering

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2019

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Vol. 20, nr 3

112--125

EN

This study uses groundwater isotopes and ion composition to verify model simulations and ecohydrological studies in the Drentsche Aa nature reserve in The Netherlands, which is representative for the northwestern wetland areas in the Ice Marginal Landscape zone. At eight field sites, a total of 24 samples were analysed for their 13C, 14C, 2H, and 18O isotopes and ionic composition. The isotopes indicate that most of the fen peatlands in the area depend on the exfiltration of sub-regional groundwater flows, which confirmed the previous model simulations and ecohydrological studies. At three sites, isotopes and ionic composition indicate that the groundwater from the sub-regional system has been replaced by local infiltrated rainwater, due to nearby groundwater abstractions for drinking water, which influenced the success rates of the restoration measures. Furthermore, the evidence from chloride and 14C contents was found to indicate the presence of more saline groundwater, which are influenced by the groundwater flows near salt diapirs. Groundwater abstractions may enhance the upward flow of the saline groundwater to eventually exfiltrate at the wetlands, affecting the biodiversity of the nature reserve.

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The contribution of geophysics to archaeology: a case study of an ancient canal of the Oc Eo culture in the Mekong Delta, Vietnam

Le Ngoc Thanh, Nguyen Quang Dung, Nguyen Quang Bac, Nguyen Quang Mien, Nguyen Dan Vu, Duong Ba Man, Nguyen Dinh Chau

Geology, Geophysics and Environment

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2019

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Vol. 45, no. 1

45--56

EN

Generally, underground ancient canals are infilled with alluvial materials, with the canal bed and substrate often having different resistivity values. This study aimed to determine the location and morphology of Malleret’s ancient canal 16 located to the southeast of the Ba The mountain, Mekong Delta, Vietnam by means of geophysical techniques. Two geophysical methods were used: electromagnetic profile and electric resisitivity tomography. A geoelectric structure 70 m long with 70–95 mS/m of apparent conductivity was found. On the electrical resistivity tomography section, a resistivity zone of 10–20 Ω∙m, 1–4 m deep, 70 m wide corresponds to the mentioned above geoelectric structure, which is in an asymmetric U-shape extending toward the southeastern bank of canal 16. Hand-augering confirmed that the canal bed is fully incised into Holocene sediments as a substrate which stretches down to the Pleistocene. The sediments are composed of loams mixed with plant remains with a resistivity ρ ~ 10–15 Ω∙m. Both of the canal banks at a depth of 5 m are made up of Holocene sedi-ments (ρ ~ 4–10 Ω∙m). The 14C measurements determined the age of the organic matter in the canal as being equal to 1210 ±85 BP, suggesting canal 16 ceased being operational at that time. The precise positioning of canal 16 on the ground surface, as well as identifying the morphology of the canal bed, were corroborated by geophysical techniques. The obtained results are of considerable value to archaeologists.

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New datings of deposits from Odra river valley - stratigraphic consequences and interpretation at fluvial succession

Gontaszewska-Piekarz Agnieszka, Szczepaniak Małgorzata

Civil and Environmental Engineering Reports

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2019

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Vol. 29, no. 3

183--199

EN

This paper presents organic sediments age analysis in Odra river valley in Słubice, western Poland. In this middle reach of Odra valley reach the uppermost fluvial deposits contain several alternate layers of organic sediments. These deposits have been mostly interpreted as the Holocene fluvial (floodplain) sediments, even if visible admixture of organic matter is not observed. However, there is also another hypothesis. Geotechnical studies conducted in several locations in Słubice, have questioned this interpretation. The main argument was the values of preconsolidation ratio in the range of 0.8 to 5.4, which may suggest, that the analysed sediments were covered by an ice sheet. Also, based on the presence of a clay layer devoid of organic matter impurities in the top of organic deposits, the second one presumes an interglacial (possibly Eemian) age of the discussed fluvial/organic sediments (peats and silts). To verify these hypotheses, six samples from six different boreholes drilled in the Odra river valley, in the centre of Słubice were collected. The results of 14C dating and its interpretation allowed to determine the age of the tested material. All analysed samples from Słubice (Odra river valley) were formed within the last 10,000 years - in Preboreal, Atlantic and Subboreal. Such a result contradicts the earlier stratigraphic interpretations.

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Recurrence interval of strong earthquakes in the se Altai, Russia revealed by tree-ring analysis and radiocarbon dating

Nepop R. K., Agatova A. R.

Geochronometria

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2018

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Vol. 45, no. 1

20--33

EN

This paper presents the results of paleoseismogeological investigations including tree-ring analysis and radiocarbon dating in pleistoseist zone of the 2003 Chuya earthquake, SE Altai, Russia. Twenty-five radiocarbon dates of previously unknown evidences of prehistoric earthquakes along the fault bounders of the Chagan-Uzun massif, North Chuya and South Chuya ranges are reported. Perspectives of applying dendroseismological approach within the high mountainous seismically active southeastern part of Russian Altai are demonstrated. In addition to estimating the germination ages of trees growing on the bare surfaces of seismically triggered landslides, analysis of wood penetrating injuries in the individual tree ring series was applied for dating paleorock-falls. Analysis of distribution patterns of tree-ring anomalies and injured trees suggests a criterion of recognizing seismic origin of past rock-falls. Dendrochronologically obtained dates of abrupt intensifications of rock-falls can be considered as supposed dates of past earthquakes, which should be verified by alternative proxy data. Obtained results argue for the high regional seismicity in the second half of the Holocene. Strong earthquakes occurred here AD 1532, and 600–700, 1300–1500, 2400–2700, 3400–3700, 3800–4200 cal BP. This data clarifies the chronology of seismic events within the SE Altai. The specified recurrence interval of strong earthquakes is about 400 years during the last 4000 years.

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Baltic Sea Holocene evolution based on OSL and radiocarbon dating : evidence from a sediment core from the Arkona Basin (the southwestern Baltic Sea)

Kostecki R., Moskal P.

Oceanological and Hydrobiological Studies

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2017

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Vol. 46, No. 3

294--306

EN

The paper presents the chronology of the Holocene evolution of the Baltic Sea based on the optically stimulated luminescence (OSL) and radiocarbon dating methods applied to a core taken from the Arkona Basin. The dating results were supplemented by grain size and geochemical analysis. The obtained results of OSL and radiocarbon dating enabled the construction of an age-depth model and confirmed the continuous sedimentation since 9900 cal yrs BP. One of the most interesting findings of this study is a clear relationship between the rate of sedimentation and fluctuations in the energy of depositional environment. The analyzed sediment core revealed two sections of different accumulation rates. The bottom section was deposited until 2700 cal yrs BP when the Ancylus Lake and the Littorina Sea were present, characterized by the accumulation rate estimated at around 0.46 mm year-1 and the dynamic sedimentation environment confirmed by grain size parameters. The accumulation rate at the top section deposited during the Post-Littorina Sea stage was estimated at around 1 mm year-1. This stage, characterized by more stable deposition and lower-energy environment conditions, was confirmed by small grain size, symmetric skewness and increasing content of organic matter.

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Sedimentary evidence of extreme storm surge or tsunami events in the southern Baltic Sea (Rogowo area, NW Poland)

Piotrowski A., Szczuciński W., Sydor P., Kotrys B., Rzodkiewicz M., Krzymińska J.

Geological Quarterly

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2017

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Vol. 61, No. 4

973--986

EN

The Baltic Sea is not typically considered as an area affected by tsunamis. However, during the Late Pleistocene and Holocene several tsunami events have been interpreted from the sedimentary record, mainly in Sweden and Estonia. Furthermore, on the southern coast of the Baltic Sea, there are historical accounts of catastrophical marine floodings called “der Seebär” (“the Sea Bear”). Their descriptions reveal many features typical for tsunami, but their genesis remained unknown and sedimentary evidence for such events has not been found. Here we provide evidence of sandy event layers from the area of Rogowo, NW Poland – the area of historical catastrophic storms as well as “der Seebär” events. The study area is a low-lying coastal plain with an average elevation of –0.5 to +0.5 m a.s.l., protected from the open sea by beach and coastal dune systems up to 5 m high. Sedimentological, micropalaeontological and geochemical analyses along with AMS 14C dating were applied to sedimentary successions seen in 5 major trenches and 198 sediment cores up to 1.5 m long. Two sandy layers were identified in the peat deposits that developed on the plain during the last ~2000 years. They reveal a number of typical features of tsunami deposits (significant lateral extent and thickness, rip-up clasts, chemical and micropalaeontological evidence of marine origin), however, 14C dating along with the historical accounts revealed that the major layer, extending at least 1.2 km from the modern coasts, was probably deposited by arguably the largest storm surge during the last 2000 years, which took place in 1497 AD. These storm deposits were likely formed during inundation of the low-lying coastal plain after major breaching of coastal dunes resulting in tsunami – like flow pattern and thus similar sedimentological effects. A discontinuous sand layer of younger age (18th century) and sharing similar properties to the previous one may be related to “der Seebär” event or another storm surge. The study revealed that the southern Baltic Sea coast may be affected by much greater coastal flooding than known from more recent accounts and observations. Thus, the presented geological record should be taken as an example of a worst-case scenario in coastal zone risk assessment from natural hazards. These events left sedimentary deposits that resemble tsunami deposits. It is likely that, in similar settings where storm surges cause unidirectional inundation of a coastal plain, it may not be possible to establish whether the resulting deposits were laid down from storms or tsunamis.

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Impact of climatic changes in the Late Pleistocene on migrations and extinction of mammals in Europe : four case studies

Baca M., Nadachowski A., Lipecki G., Mackiewicz P., Marciszak A., Popović D., Socha P., Stefaniak K., Wojtal P.

Geological Quarterly

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2017

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Vol. 61, No. 2

291--304

EN

Climate changes that occurred during the Late Pleistocene had profound effects on the distribution of many plant and animal species and influenced the formation of contemporary faunas and floras of Europe. The course and mechanisms of responses of species to past climate changes are now being intensely studied by the use of direct radiocarbon dating and genetic analyses of fossil remains. Here, we review the advances in understanding these processes by the example of four mammal species: woolly mammoth (Mammuthus primigenius), cave bear (Ursus spelaeus s.l.), saiga antelope (Saiga tatarica) and collared lemmings (Dicrostonyx ssp.). The cases discussed here as well as others show that migrations, range shifts and local extinctions were the main responses to climate changes and that the dynamics of these climate-driven processes were much more profound than was previously thought. Each species reacted in its individual manner, which depended on its biology and adaptation abilities to changing environmental and climatic conditions. The most severe changes in European ecosystems that affected the largest number of species took place around 33–31 ka BP, during the Last Glacial Maximum 22–19 ka BP and the Late Glacial warming 15–13 ka BP.

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Pleistocene glaciations of the SE Altai, Russia, based on geomorphological data and absolute dating of glacial deposits in Chagan reference section

Agatova A. R., Nepop R. K.

Geochronometria

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2017

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Vol. 44, no. 1

49--65

EN

Geomorphological evidence of at least two Pleistocene glacial epochsis noted within the Chagan-Uzun river basin, SE Altai. A review and analysis of all available absolute dates for reference Chagan section is presented. The highest correlation amongst all TL dates is observed for the lens of glacio-lacustrine sediments – the most suitable among glacial deposits for luminescence dating, and indicates its possible Middle Pleistocene age. IRSL dates obtained from feldspar indicate a Middle Pleistocene age of moraines already in the upper part of the section. The small number of obtained IRSL dates does not allow making geochronological reconstructions of the Pleistocene glaciations, but gives the possibility for further experiments with different variation of OSL (IRSL) techniques. Strong low temperature peak in TL signal and strong response to IR stimulation are specific regional quartz features, which could be explained by combination of short transportation distance and low number of depositional cycles for mineral grains. Available radiocarbon dates of carbonate concretions from this section are not related to the age of moraine sedimentation and most likely indicate the period of the Chagan river incision into the ancient glacial deposits. This study has shown that TL method is not valid for dating glacial sediments and TL dates cannot be utilized as chronostratigraphic markers. Generally, the Chagan section could hardly serve as a reference section for the Altai stratigraphy; available depositional correlation schemes for the Russian Altai and Siberia which are based on several TL dates obtained in the last century needs to be improved.

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Early Holocene alluvia in the lower Wisłok River valley and their chronostratigraphy in the light of radiocarbon datings and palynological analysis

Superson S., Gębica P., Michczyński A., Kołaczek P., Szczepanek K.

Geochronometria

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2017

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Vol. 44, no. 1

216--225

EN

The paper presents the results of the latest radiocarbon dating and the palynological analyses of organic sediments found in the alluvia of the Wisłok River valley between the towns of Łańcut and Przeworsk. The study conducted in the gravel pit made possible the dating of several alluvial fills of the 7–8 m high Holocene terrace and the 5–6 m high floodplain. The oldest channel alluvia and palaeochannel sediments of the 7–8 m high terrace were dated at 10 100–9300 BP (11 960–10 500 cal BP). According to the anthracological analysis the top cover of clay overbank alluvia, which bears charcoal fragments, was deposited in the Subboreal and/or the Subatlantic Phases. In the sequence of the 5–6 m high floodplain, the bottom fills of palaeochannels, dated at 10 195–9885 cal BP (probability level: 68.2%; GdS-3233: 8900 ± 95 BP ) and 11 095–10 755 cal BP (probability level: 68.2%; GdS-3228: 9575 ± 95 BP), were truncated by erosion and covered by alluvia of palaeomeanders, which were active in the 19th century. Preservation of the erosional bench of the Early Holocene organic sediments indicates the predomination of lateral migration of the river channel during the last 200 years and the formation of wide erosional floodplain that has been aggraded with recent flood alluvia. In the 20th century the floodplain aggradation was simultaneous with the deepening of the Wisłok riverbed.

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Benefits and weaknesses of radiocarbon dating of plant material as reflected by Neolithic archaeological sites from Poland, Slovakia and Hungary

Nowak M., Moskal-Del Hoyo M., Mueller-Bieniek A., Lityńska-Zając M., Kotynia K.

Geochronometria

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2017

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Vol. 44, no. 1

188--201

EN

Radiocarbon dating of the plant material is important for chronology of archaeological sites. Therefore, a selection of suitable plant samples is an important task. The contribution emphasizes the necessity of taxonomical identification prior to radiocarbon dating as a crucial element of such selection. The benefits and weaknesses of dating of taxonomically undetermined and identified samples will be analysed based on several case studies referring to Neolithic sites from Hungary, Slovakia and Poland. These examples better illustrate the significance of the taxonomical identification since plant materials of the Neolithic age include only a limited number of cultivated species (e.g. hulled wheats) and typically do not contain remains of late arrived plants (e.g. Carpinus betulus and Fagus sylvatica). For more accurate dating results cereal grains, fruits and seeds, which reflect a single vegetative season, are preferred. Among charred wood, fragments of twigs, branches and external rings should mainly be taken into account, while those of trunks belonging to long-lived trees should be avoided. Besides the absolute chronology of archaeological features and artefacts, radiocarbon dating of identified plant remains might significantly contribute to the history of local vegetation and food production systems.

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Absolute chronology of the Zedmar culture: Re-thinking radiocarbon dates

Kozicka M.

Geochronometria

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2017

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Vol. 44, no. 1

256--268

EN

The Zedmar culture is linked with the subneolithic circle of the South-Eastern Baltic region. So far, excavations have been carried out only on seven archaeological sites. Nonetheless, there are quite a lot of radiocarbon measurements. Most of them refer to the stratigraphic contexts. This allows to integrate all of the data into statistical models. With these, it is possible to query some statements about the Zedmar culture origin and its duration. At least as long as placing the Zedmar culture into an absolute timescale may offer any solution to those issues. The idea that radiocarbon dates could provide solutions or even final answers to some arguable questions in prehistorical studies was dropped, as soon as it became clear that in the whole approach the key role is played by calibration methods and the general variability of sampled material. However – thanks to including Bayesian analysis, a better understanding of dated materials and more complex examination of received results – it has been asserted again.

16

The oldest traces of human settlement in the vicinity of Ulów in Middle Roztocze (SE Poland)

Wiśniewski T.

Folia Quaternaria

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2017

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nr 85

49--64

EN

During the many years of archaeological research in the settlement micro-region in Ulów in Middle Roztocze, traces of human presence dated to Old and Middle Stone Ages (Palaeolithic and Mesolithic) were discovered. M ost sources are flint materials, most of which lost their stratigraphic context due to subsequent settlement. At the current stage of research, their classification is possible only on the basis of a typological and comparative analysis. M ost likely, the oldest traces of human occupancy in the vicinity of Ulów can be synchronized with a series of radiocarbon dating obtained for samples of charcoal from five different archaeological sites. The to-date discoveries have revealed new sources for research on the Palaeolithic and Mesolithic periods in south-eastern Poland.

17

Age and evolution of the Littorina Sea in the light of geochemical analysis and radiocarbon dating sediment of cores from the Arkona Basin and Mecklenburg Bay (SW Baltic Sea)

Kostecki R.

Landform Analysis

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2015

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Vol. 29

27--33

EN

Two sediment cores from the Mecklenburg Bay and Arkona Basin were analysed in terms of their geochemical composition and stratigraphy. The main stages of the Baltic Sea evolution – Baltic Ice Lake, Ancylus Lake, and Littorina Sea – were identified in both analysed cores. The most pronounced period was the transition between the Ancylus Lake and the Littorina Sea. The character of the initial stage of the Littorina Sea was clearly defined in the Mecklenburg Bay sediments and is marked by a stepwise increase in loss on ignition and contents of biogenic silica, calcium, magnesium, iron, and strontium. The record of the onset of the Littorina Sea in the Arkona Basin sediments is marked by an abrupt change of the geochemical parameters. The age of the initial Littorina Sea in the Mecklenburg Bay was estimated at about 8200 cal years BP and was probably older than the transgression within the Arkona Basin.

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Stages of the Baltic Sea evolution in the geochemical record and radiocarbon dating of sediment cores from the Arkona Basin

Kostecki R.

Oceanological and Hydrobiological Studies

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2014

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Vol. 43, No. 3

237--246

EN

Four sediment cores from the southern part of the Arkona Basin were analyzed in terms of their geochemical composition, age and stratigraphy. The main stages of the Baltic Sea: the Baltic Ice Lake, the Ancylus Lake and the Littorina Sea were identified in all the analyzed cores. The data confirmed the high water fluctuation and significant environmental changes during the Baltic Sea evolution in the Late - Glacial and the Holocene. The signs of the second regression of the Baltic Ice L ake, dated at around 11 000 cal BP, were identified at a depth of 24 m b.s.l. Regression of the Ancylus Lake, dated at 9300 cal BP, was identified at a depth of 23 m b.s.l. The most pronounced period was the transition stage between the Ancylus Lake and th e Littorina Sea. The record of the Littorina Sea onset in the sediments of the Arkona Basin is marked as a sudden increase in loss on ignition, biogenic silica, magnesium, calcium, iron and strontium. The age of the Littorina Sea in the Arkona Basin was es timated as younger than 8200 cal BP.

19

Nowoczesna dendrochronologia i jej pionierzy

Wandelt P

Przegląd Papierniczy

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2013

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R. 69, nr 1

51--58

PL

Dendrochronologia jest naukową metodą datowania wydarzeń, zjawisk przyrodniczych i obiektów zabytkowych zawierających drewno, a także badania klimatu w przeszłości, czym zajmuje się dendroklimatologia, na podstawie porównywania i liczenia pierścieni przyrostów rocznych w drzewie, przy czym nie trzeba go ścinać i przeżynać, bo podstawowym narzędziem dendrochronologa jest specjalny świderek pozwalający z żywego, rosnącego nawet drzewa pobrać próbkę wszystkich słojów w przekroju drewna, wyciągając ją tym świdrem (rys. 1), jak korek z butelki wina. Metoda ta wcale nie musi być inwazyjna i szkodzić drzewu, gdyż podobnie robiliśmy w fińskim lesie z kolegą wykonującym w Fińskim Instytucie Celulozowo-Papierniczym pracę licencjacką, wprowadzając w nawiercone otworki aerosol paraquatu, w celu zwiększenia wydzielania przez drzewo związków żywicznych.

EN

The article describes how astronomer A. Douglass was searching some evidence of periodic sunspot cycles in tree rings and how his former student E. Schulman discovered the oldest bristlecone pine trees which allowed to recalibrate a radiocarbon dating method, rewriting history and origin of our European civilisation.

20

Holocene tufa in the Slovak Karst : facies, sedimentary environments and depositional history

Gradziński M., Hercman H., Jaśkiewicz M., Szczurek S.

Geological Quarterly

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2013

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Vol. 57, No. 4

769–-788

EN

Several tufa complexes are known in the Slovak Karst which is a typical karst area of a temperate climate. This area is built of Mesozoic carbonates, mainly Triassic in age. The karst systems drain carbonate plateaux and lead water to resurgences located in valleys which are up to 300 m deep. Below the resurgences there are Holocene fossil tufa deposits that exceed 12 m in thickness. The tufas include stromatolite, moss, phytoclastic, oncoidal, and intraclastic facies. Extensive barrages which once dammed the upper reaches of the streams were formed in narrow valleys. They are composed predominantly of moss facies and stromatolites, with subordinate oncoidal and phytoclastic facies. Phytoclastic, oncoidal and intraclastic facies are dominant in dammed segments of streams, and include gastropod shells and charcoal fragments. Some small moss cushions are also developed. Barrages and dammed areas formed in a longitudinal fluvial depositional system. Conversely, below resurgences located on plateau slopes tufas of a perched springline depositional system were formed. These comprise deposits of prograding cascades constructed by moss, phytoclastic and stromatolitic facies. Presently, the tufas analysed are inactive. They stopped growing in the Late Holocene time, after which there was abrupt incision of the streams. This caused downcutting into Holocene tufas, in some places reaching Mesozoic bedrock. At present tufa is being precipitated from streams in all the sites studied.