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Impact craters are formed by collisions of cosmic bodies moving with hypervelocity. The formation of these features is not restricted to the distant geological past; new structures are constantly being created and at least 13 confirmed impact craters and crater fields have formed during the Holocene alone. This short review paper: (1) introduces the basics of the impact cratering process to physical geographers and Quaternary geologists; (2) provides a short description of representative examples of such features (Morasko, Kaali, Kamil, Ilumetsa); and (3) discusses the similarities and differences among very small craters, and contrasts these with larger impact structures. This manuscript may be useful to researchers planning to test whether a small Quaternary depression in the ground may be of impact origin. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The paper presents the history of diatom studies carried out in the Gulf of Gdańsk and the Vistula Lagoon since the beginning of the 20 century. One aspect of the research focuses on describing the structure of planktonic and benthic communities living in different parts of the area or occurring in their surface sediments as taphocoenoses. Other investigations concentrate on the fossil diatom flora, which is widely used in the research on the Late Glacial and Holocene to resolve paleogeographic, sedimentological and paleoecological problems. [ABSTRACT FROM AUTHOR]

In this paper, a lithological study taking into account trace metals of the profundal sediments from Slupiañska Bay in Wigry Lake is presented. A profile 5.26 m long has sandy muds at the bottom and moving upwards layers of calcareous gyttja, lacustrine chalk, and again calcareous gyttja are present. The profile is continuous, typical for the sediments of NE Poland formed from Aller&3x00F8;de to recent time. The results of the lithological analysis were correlated with results of high-resolution seismic survey. The results together with radiocarbon dating are part of interdisciplinary complex re- search comprising paleobiological study of pollen, Cladocera, diatom successions and human activity, which will be published in successive papers. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The paper reports the results of a palynological study of a newly exposed section in the peat sediments of Bezděkov site and its correlation with the previous palaeobotanical studies. The main goal was to elucidate the stratigraphic position and paleogeographic development of fossil peat bog and its environment in the Protected Landscape Area Žďárské vrchy and Železné hory in the Bohemian-Moravian Uplands. The development of peatbog vegetation, as shown by the pollen analysis and radiocarbon dating, took place in the Holocene. Pollen analyses provide evidence for occurrences of wetland assemblages with huge representation of alder wood in all the part of succession, followed by willow near the Cerhovka Brook. Alnus and Abies were the dominant trees during all the time. The deciduous forests consist of elm ( Ulmus), oak ( Quercus), lime tree ( Tilia), maple ( Acer) and hazel ( Corylus). The mosaic picture of woodland and wetland, which covered this landscape during the Upper Holocene, contrasts with the present day monotonous open lowland. Sediments of the peat bog provide information on the origin and vegetation evolution of this area. [ABSTRACT FROM AUTHOR]

In this paper all the Stone Age and Early Metal Period (ca. 8600 cal BC - 300 AD) radiocarbon dates from the Karelian Isthmus, Russia, are compiled and their archaeological usability assessed using a set of evaluation principles. The quality of radiometric dates from such a large area has rarely been methodologically examined in Finnish or North-West Russian archaeology, and is applied here for the first time on the present material. Special attention is given to the discussion on the deficiencies and limitations of the current data. Based on the 81 dates evaluated as useful, a tentative radiocarbon chronology is presented for the study area. This is generally in sequence with the chronologies of the nearby areas, but suggests some differences especially towards the end of Stone Age, as well as the presence of biases caused by taphonomic and research-related factors. [ABSTRACT FROM AUTHOR]

This paper demonstrates the results of analyses of Cladocera, pollen, plant macrofossil, lithological and radiocarbon data recovered from a mire located in the Rawka River valley in central Poland. These studies permit to recognise the development of hydrology phases in Kopanicha mire and give insight into Holocene fluvial dynamics of the system; radiocarbon dating partly allowed da-ting of the patterns of Holocene valley floor development of the Rawka River. The Kopanicha mire was formed during the Atlantic period. At that time, an oxbow lake formed, becoming a mire during the Subboreal and possibly Subatlantic periods. The high sensitivity of the oxbow lakes, fens, fauna, and flora remains to climate variations - especially to changes in water level connected with the ag-gradation-erosion cycle of rivers - allows the reconstruction of the palaeoecological changes that oc-curred in the mire. The frequency and timing of hydroclimatic oscillations at Kopanicha show strong similarities to records from other sites in Poland. Changes in Cladocera frequency and plant assem-blages were mostly influenced by the Rawka River which controlled the hydrological regime of the mire. The main factors controlling the presence of Cladocera taxa were the water level and the pres-ence of favourable conditions in the mire (e.g. pH, vegetation). Most of the changes occurred in re-sponse to climate changes, but some of them were connected with local factors. [ABSTRACT FROM AUTHOR]

The paper presents the results of interdisciplinary (multiproxy) palaeoenvironmental studies of peat - calcareous tufa depositional sequences of spring mire from Radzików site (east Poland). Analyses of three biotic proxies (plant macrofossils, pollen, molluscs) were supplemented with sedimentological, geochemical, oxygen and carbon stable isotopes analyses and radiocarbon dating and used for reconstruction of environmental changes in Late Glacial and Holocene. The obtained results enable us to (1) reconstruct main phases of mire development and (2) determine environmental factors influencing changes of water supply. The object started to develop in Allerød. The Late Glacial and Early Holocene deposit sequence is relatively thick (about 1.0 m), with good palaeoecological record. The boundary between Younger Dryas and Preboreal is especially well confirmed by palynological and malacological analyses as well as radiocarbon dating. The Mesoholocene deposits are considerably worse preserved. Mire development was evaluated in terms of general mire ecology. [ABSTRACT FROM AUTHOR]

In this paper, a detailed overview of the Holocene evolution of the North Dvina river (ND) delta (southern White Sea) is presented; it is based on radiocarbon dating, geomorphological and other field surveys, and plant macrofossil and palynological data. We have identified three main stages of the delta evolution: estuary erosional (Allerød - 5700 cal BC), lagoon or tidal-marsh (5700 cal BC - 3700 cal BC) and fan-delta accumulative (3700 cal BC - present). These stages are correlated with local climatic curves, sea level changes, glacioisostatic raise curve and Baltic Sea stages. A variety of landforms has been identified and dated within the delta. These results help to explain the spatial and temporal patterns in the prehistoric human occupation of this area. [ABSTRACT FROM AUTHOR]

The paper presents the results of the AMS radiocarbon dating of moss macrofossils which seem to be too old in the context of palynological data. The lack of agreement between the obtained results of radiocarbon dating and pollen analysis has been discussed. Some possible causes of the discrepancies between the results of radiocarbon dating and palynological dating have been given. [ABSTRACT FROM AUTHOR]

This article presents results of diatom analysis of seven sediment cores taken from various depths of the Gulf of Gdańsk between the Hel Peninsula and the coast of Gdańsk and Gdynia. Further eight cores were drilled in the northern, southern and central part of the Vistula Lagoon. The present investigations enabled the determination of: (i) differentiation of diatom assemblage zones, (ii) correlation of palaeoecological units with reference to the following stages: Mastogloia Sea, Littorina Sea, Post-Littorina Sea, including the latest environmental changes associated with an anthropogenic factor, (iii) description of the defined diatom biofacies based on statistical analysis, (iiii) reconstruction of spatial and temporal development of both basins with the emphasis on the role of inflows of sea and river waters. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyze resting spores of Chaetoceros spp. preserved in Middle and Late Holocene sediments of the three parts of the Gulf of Gdańsk, southern Baltic Sea. The material studied consists of ten cores retrieved from Kuźnica Deep (Puck Lagoon), as well as the shallower and deeper parts of the Outer Puck Bay region. Our results indicate that the abundance of Chaetoceros resting spores in diatom taphocoenoses corresponded to regional and local paleoecological changes registered in Mastogloia, Littorina and Post-Littorina sediments, and that they also reflect human impact in the last hundred years. [ABSTRACT FROM AUTHOR]