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The climate variability and related sea-level changes during the Holocene are still under discussion, especially in a regional context. Very little information comes from the southern and south-eastern Baltic coast. The aim of the paper is to gain insight on the history of regional environmental changes, particularly sea-level and storminess, and their driving forces. The investigations were located on a peatland on the coast of Puck Lagoon (Gulf of Gdańsk, southern Baltic Sea). The analysis of peat core comprised: radiocarbon dating, analysis of stable isotopes 18O and 13C and chemical components, as well as palynological and diatomic studies. Results showed the 1.0 m peat section accumulated over 1500 years, with a time resolution of 100 years per sample. The average water level in the Puck Lagoon rose by ca. 0.85 m during the last 1500 years in a cyclic mode, with a period cycle of ca. 600–550 years and an amplitude not exceeding 0.5 m. The accelerated sea level rise and frequent storminess occurred during the first half of the Dark Ages (1500−1300 years b2k) and LIA (750−450 years b2k) and since the beginning of the 20th century. Recognized environmental changes are well correlated with both temperature changes in the North Atlantic and changes in total solar irradiance, suggesting synchronous Northern Hemisphere-wide fluctuations. The solar forcing was an important constituent of natural climate variability in the past and of forcing climate warming during modern times - after the Little Ice Age. [ABSTRACT FROM AUTHOR]

The climate of east-central Europe (ECE) is the result of a combination of influences originating in the wider North Atlantic realm, the Mediterranean Sea, and the western Asian and Siberian regions. Previous studies have shown that the complex interplay between the large-scale atmospheric patterns across the region results in strongly dissimilar summer and winter conditions on timescales ranging from decades to millennia. To put these into a wider context, long-term climate reconstructions are required, but, largely due to historical reasons, these are lacking in ECE. We address these issues by presenting a high-resolution, radiocarbon-dated record of summer temperature variations during the last millennium in ECE, based on stable isotope analysis of a 4.84 m long ice core extracted from Focul Viu Ice Cave (Western Carpathians, Romania). Comparisons with both instrumental and proxy-based data indicate that the stable isotope composition of cave ice records the changes in summer air temperature and has a similar temporal evolution to that of the Atlantic Multidecadal Oscillation on decadal to multidecadal timescales, suggesting that changes in the North Atlantic are transferred, likely via atmospheric processes towards the wider Northern Hemisphere. On centennial timescales, the data show little summer temperature differences between the Medieval Warm Period (MWP) and the Little Ice Age (LIA) in eastern Europe. These findings are contrary to those that show a marked contrast between the two periods in terms of both winter and annual air temperatures, suggesting that cooling during the LIA was primarily the result of wintertime climatic changes. [ABSTRACT FROM AUTHOR]

In this study, we investigated morphologically and geochemically a skull from an open pit situated on the Călineasa-Şesu Gârzii Plateau, Bihor Mountains. The study presents the first 14C dating and stable isotope composition of bison skeletal remains from the Romanian Carpathians. The result of 14C determination yielded two relevant maxima: one is around AD 1550 and the second around AD 1645. The data indicate that the investigated bison died during the ‘Little Ice Age’ (LIA), approximately 200 years before the last ones were hunted to extinction. Stable isotope composition of carbon from bison tooth enamel suggests that the bison diet consisted mainly of C3 grasses, compatible with a high-altitude habitat, vegetation distribution and low mobility. Oxygen isotope composition of both phosphate and carbonate groups of tooth enamel indicates that the bison drank from stagnant water sources, such as lakes or puddles formed from rain water. This further suggests low mobility of the bison as well, as the presence of such small stagnant water sources is characteristic even today for the plateau. Calculated oxygen isotope compositions of rain and drinking water at the time the bison lived indicate a lower relative humidity, around 60–70% at that period of LIA when the bison lived, which is lower than today’s humidity of 80%. [ABSTRACT FROM AUTHOR]

In the rich of archaeological sites dated from the late Palaeolithic to the Modern Period region of the Serteyka River, deposits of an extensive accumulative fan were studied in detail. In the lower sector of the present-day Serteyka River valley, the strict chronology and depositional conditions of an extensive accumulative fan deposits were studied in detail. An important part of the project has been also: a checking of usefulness of luminescence, radiocarbon and lead methods of dating in determination of the age of inorganic deposits accumulation The 14C, optically stimulated luminescence (OSL), and 210Pb dating methods were used to determine the fan's deposition age. Then, we discussed the depositional conditions of the accumulative fan by the textural, geochemical, and palaeoecological analysis. The use of 14C and 210Pb methods of dating allows for elaboration of a reliable model of the evolution of slope processes occurring from the 2nd half of 17th c. AD to 2nd half of 19th c. AD (i.e. during the younger part of the Little Ice Age). It was a period of human induced deforestation, as confirmed by the first results of palaeobotanical analyses. In addition, four OSL dates have been obtained, but the acquired age significantly exceeded previous expectations. Three dates indicate the Neolithic period, and a chronological inversion of OSL dates can be seen. This may be due to incomplete bleaching of the sand grains during transport, which indicates that the material being transported had a relatively large volume. The lower deluvium of the accumulation fan is formed by the drainage of hydrated sediment (mudflows). Summarizing, slope sediments can be extremely difficult material for absolute dating. This may be due to the redeposition of the material, the hiatuses in deposition and incomplete bleaching of quartz grains. In the case of 14C (AMS) dating, the dependence is on the presence of plant macroremains within the studied material. In the case of slope deposits, there is a very high probability of the redeposition of organic material. Lead dating, on the other hand, has a small chronological range. Moreover, the dating of inorganic sediments with this method poses many problems, including of a methodological nature. In the tested accumulative fan, as a result of insufficient grain whitening and the short chronological range of the 210Pb method, the 14C method was the main analysis determining the age of inorganic sediments. [ABSTRACT FROM AUTHOR]

The Carpathian Mountains host several ice caves that preserve a large variety of geochemical information on past climate and environmental changes. In such caves, ice forms in winter by the freezing on infiltrating water, the later accumulating during the rainy season, between early summer and late autumn (depending on site-specific conditions). Here, we present the first reconstruction of summer temperature during the last 1000 years based on the d18O and d2H values measured in Focul Viu Ice Cave (Western Carpathian Mountains, Romania).Focul Viu (FV) is short (107 m long) descending cave, located at ca. 1165 m above sea level on the windward (western) side of the mountains. A stratified ice block, with a volume of ~25000 m3 and ~20 m thickness, occupies the floor of the cave. In May 2016 we have extracted a 4.86 m long ice core from the cave glacier and measured the stable isotope composition of ice in order to derive information on past climate variability. The chronology of the core is based on six 14C measurements on organic matter embedded in the ice. Monitoring of the stable isotope composition of precipitation in the vicinity of the cave shows that most of the summer precipitation is originating in the Atlantic Ocean, ca. 30 % percent of it being locally recycled during heavy summer storms.We have found a near-perfect correlation between d18O (and d2H) of the ice core and instrumental summer temperatures measurements at three local stations, located west, north and east of the cave's location and have used this correlation to reconstruct summer temperature variability during the past ~1100 years. Our results show little centennial-scale variability during this period, suggesting that summer temperatures were likely similar between the Medieval Warm Period (MWP) and the Little Ice Age (LIA). In contrast, winter temperatures reconstructed from the nearby Scărișoara Ice Cave clearly show lower temperatures during the LIA, compared to the MWP, suggesting that the well-known temperature contrast between the two periods was a the result of winter climatic conditions. On a decadal scale, both during the MWP and the LIA, summer temperatures fluctuated with a periodicity of ~20/30 years, the minima and the maxima matching the fluctuations recorded by the Atlantic Ocean sea surface temperatures. Both the periodicity and the observed variability are similar to those of the Atlantic Multidecadal Oscillation, suggesting the d18O and d2H values in FV cave ice are recording climatic changes at hemispheric scale, thus being an important new proxy for both past temperatures and large-scale circulation changes. [ABSTRACT FROM AUTHOR]