35 research outputs found
Pingo Nori (Spitsbergen) massive ice isotope and chemical content of permafrost core Grondalen 13
No full textThe drilling of the 10.5 m high Nori pingo that stands at 32 m asl in Grøndalen Valley (Spitsbergen) performed in April 2019 reached a depth of 21.8 m bs (core #13, starting from 42.5 m asl, 77.99483 °N, 14.59009 °E) and revealed 16.1 m thick massive ice. The core was obtained with a portable gasoline-powered rotary drilling rig (UKB 12/25, Vorovskiy Machine Factory, Ekaterinburg, Russia). The core pieces with diameter 112-76 mm were lifted for sampling to the surface every 30–50 cm. After documentation and cryolithological description core pieces were sealed in zip lock bags. Ice samples were split in two parts - one part for stable isotope analyses, another part for ion content measurement. They were kept frozen for transportation while sediment samples were kept unfrozen. Moisture content was analyzed in laboratory by measuring sediment samples weight before and after drying.
The stable water isotope composition (δ18O and δD) of massive pingo ice was analyzed at the Climate and Environmental Research Laboratory (CERL, Arctic and Antarctic Research Institute, St. Petersburg, Russia) using a Picarro L2120- i analyzer. After every five samples the working standard (SPB-2, δ18O = -9.66 ‰ and δD = -74.1 ‰) was measured. SPB-2 is made of distilled St. Petersburg tap water and is calibrated against the International Atomic Energy Agency (IAEA) standards VSMOW-2 (Vienna Standard Mean Ocean Water 2), GISP (Greenland Ice Sheet Precipitation), and SLAP-2 (Standard Light Antarctic Precipitation 2). The reproducibility of the results is 0.08 ‰ for δ18O and 0.4 ‰ for δD and was assessed by re-measuring a random selection of 10% of the total samples. The measurement error is thus 1-2 orders of magnitude less than the natural isotopic variability of pingo ice, which is satisfactory for the purpose of this study. The δ18O and δD values are given as per mil (‰) difference to the VSMOW-2 standard. The deuterium excess (d) is calculated as d = δD - 8δ18O29.
The ion content of sedimentary permafrost samples from core #13 was estimated after water extraction at the analytical laboratory of RAE-S, Barentsburg. The material was dried and sieved at 1 mm. About 20 g of the sediment were suspended in 100 ml of de-ionized water and filtered through 0.45 μm nylon mesh within 3 minutes after stirring. Electrical conductivity (EC, measured in μS cm-1) and pH values were estimated with a Mettler Toledo Seven Compact S 220. EC values were transformed automatically by the instrument into general ion content (mineralization) values given as mg L-1. Major anions and cations in the water extracts were analyzed by an ion chromatograph (Shimadzu LC-20 Prominence) equipped with the Shimadzu CDD-10AVvp conductometric detector and ion exchange columns for anions (Phenomenex Star-ion A300) and for cations (Shodex ICYS-50). Bicarbonate content was measured by a Shimadzu TOC-L analyzer via catalytic oxidizing at +680o C and subsequent infrared detecting. Melted pingo ice samples from core #13 and spring water samples were analyzed after filtration through 0.45 μm nylon mesh on the same equipment using the same techniques for pH, EC, and ion composition as for sedimentary permafrost samples.
Analyses and research were aimed at determining major characteristics of the Nori pingo including its internal structure, groundwater source, and geochemical and isotopic stages of formation
Intra-Annual Variability of the Surface Ablation of the Aldegondabreen Glacier (Spitsbergen)
No full textThe intra-annual variability of the surface ice ablation on the 5.5 km2 Aldegondabreen glacier (Spitsbergen Island, Barentsburg area) is presented. The ice ablation was measured during five seasons (2018–2022) at the two stakes, installed in the lower part of the glacier and at the index site, where the amount of ablation numerically coincides with the glacier-averaged value with the r = 0.99 agreement. The temporal resolution of the ice ablation data is uneven and varies from 3 to 45 days. To carry out the correlation analysis, meteorological data from the automated weather station located near the glacier terminus are used. The ice ablation rates, obtained after normalization for the number of days between stake readings, have a tight correlation with both the air temperature and the downwelling shortwave radiation flux for most of the seasons, in 2018– 2021 (r = 0.71–0.99). Surface air temperature and short-wave radiation are closely related; the above estimates indicate the leading role of short-wave radiation in the summer ablation of the glacier in the period 2018–2021. The year 2022 became anomalous, as the correlation with the shortwave radiation significantly decreased (r = 0.21–0.34). The European heat wave of 2022, which also affected the Svalbard archipelago, interrupted the ordinary intra-annual variability of the air temperature, causing the unprecedented ice melt on Aldegondabreen in September. The predicted increase in frequency and intensity of the future heat waves will result in an increased role of turbulent fluxes in the surface energy balance of the low-elevated Svalbard glaciers. The article demonstrates how the empirically identified dependencies can change from season to season in a non-stationary climate
Sediment and ice characteristics of permafrost cores from Barentburg area, Westspitsbergen
No full textTo gain new understanding in this context a total of 19 drill cores complemented by one natural exposure reaching depths below surface between 5 and 25 m was studied, corresponding to sampling heights between 74 m above sea level and 4 m below sea level. The drill transect stretches along about 20 km from the marine terraces at the Isfjorden, along the Grønfjorden and the Grøndalen and Iradalen valleys in the wider area of Barentsburg. Detailed cryolithological descriptions, hydrochemical and sedimentological analyses, and radiocarbon dating were applied to deduce the spatial and temporal evolution of regional permafrost after deglaciation and sea-level adjustment
Radiocarbon dating of lacustine and marine sediments from the Bunger Hills, East Antarctica
No full textHydrochemistry of water extracts and of ground ice and ice contents of permafrost cores from Barentburg area
No full textParts of the analyses have been carried out in the laboratories of the Russian Scientific Arctic Expedition on Spitsbergen Archipelago (RAE-S) Barentsburg Station. Gravimetric moisture content (ice content) was measured by weighing samples before and after drying at 50°C to relate the weight loss to the total weight of dry samples, expressed as weight percentage (wt%). Hydrochemical analyses of sedimentary permafrost samples was undertaken after water extraction. The material was dried and sieved at 1 mm. About 20 g of the sediment were suspended in 100 ml de-ionised water and filtered through 0.45 µm nylon mesh within 3 minutes after stirring
Postglacial relative sea level change at Fildes Peninsula, King George Island (West Antarctic)
Get PDFAnalysis and integration of data obtained in our field and laboratory investigations of 2008–2012 together with results of previous paleogeographic studies were conducted to reveal parameters and factors of the post-glacial changes in the relative sea-level on the Fildes Peninsula and the King George Island. Results of dating of organic material taken from cross-sections of Quaternary deposits, data on morphology of marine landforms as well as on bottom sediments in lakes were used to construct a curve of changes in the relative sea-level.Our research has shown that the rapid rise of relative sea level in the area (since the beginning of the Holocene) decelerated about 8000 years BP, achieving its maximum about 7000 years BP. This was followed by the fall of relative sea-level (the land elevation) by 18–20 m in total, and it was characterized by relatively high rate of fall during periods of 6000– 5000 years BP, 4000–2500 years BP, and during the last 1500 years; the rate decreased in 5000–4000 years BP and 2500– 1600 years BP. The changes in relative sea level in this region were determined by the following factors: the eustatic component of the global changes in sea-level and, possibly, oscillations in the global sea level of another nature; local parameters of the Last glacial maximum; a course of the Peninsula deglaciation; regional physical characteristics of the Earth's crust and the mantle substances; local tectonic processes, including the isostatic rebound. Since the beginning of the Holocene up to about 7000 years BP, the main contribution to changes of the relative sea-level in this area was made by the global eustatic factor. The subsequent fall of the relative sea-level (elevation of the Peninsula surface) proceeded under condition of reduced role of the eustatic factor and predominance of other factors
Late Pleistocene and Holocene environmental history of Bunger Hills, East Antarctica, as revealed by fresh-water and epishelf lake sediments
No full textHolocene environmental changes and development of Figurnoye Lake in the southern Bunger Hills, East Antarctica
No full textStructure and dynamics of Aldegondabreen, Spitsbergen, according to repeated GPR surveys in 1999, 2018 and 2019
Get PDFOver the last decades, glaciers on Svalbard were shrinking in response to the current climate change. Most of them decreased in size, area, and surface height with a stable negative or even accelerated changes in the mass balance. Many of them belong to the polythermal type, and as they shrink, their thermal regime can also change significantly depending on the climate and local parameters such as the ice facies distribution, the firn thickness, and others that affect the hydrology and movement of glaciers. Data from repeated GPR surveys in 1999 and 2018–2019 were used to identify changes in the thermal regime of the polythermal Aldegondabreen, Svalbard. The glacier has undergone a significant reduction of its temperate ice core, as a consequence of steadily negative mass balance, decreasing thickness, and the tongue retreat. The results show that over a 19‑year period, the total area of the glacier has decreased by 23.1% (from 6.94 to 5.34 km2), and the total volume of ice – by 36.4% (from 0.437 to 0.278 km3). At the same time, the area of its temperate core has decreased by 32.7% (from 1.196 to 0.804 km2), and the core volume – by 42.5% (from 0.035 to 0.02 km3). In this way, the relative rates of internal glacier changes associated with the warm core exceeded the external changes of the entire glacier. The share of temperate ice in the total volume of the glacier ice decreased from 8% to 7%. The glacier shrinking in response to rise of the air temperature was accompanied by its gradual internal «cooling». In the near future, this can result in a rapid transition of the glacier from a polythermal type into a cold one. Regular repeated geophysical surveys of the internal structure of the Svalbard polythermal glaciers can become an important element in the system of long-term monitoring of changes in climate and the natural environment of the archipelago, along with already existing observations of other sensitive natural indicators such as the size and mass balance
Stable isotopic composition of atmospheric precipitation and natural waters in the vicinity of Barentsburg (Svalbard)
Get PDFIn 2016–2017, during Russian Arctic Expedition on Svalbard (RAE‑S) we have collected the samples of atmospheric precipitation, terrestrial waters, snow and ice on Spitsbergen island in the vicinity of Grønfjorden. The measurements of stable water isotope content (δ18O and δD) in the atmospheric precipitation has allowed to draw the Local Meteoric Water Line (δD = 6,93δ18O − 0,35) and to analyze the relationship between the isotopic content and condensation temperature. Aside from this, the d-excess values in precipitation (dexc= δD − 8δ18O) was interpreted as a marker of the moisture source. It has been demonstrated that the isotopic content of the surface waters (lakes and rivers) clearly points to the dominating type of feeding (atmospheric, ground) of these hydrological objects. We have discovered the interannual variability of the isotopic composition of Lake Kongress water during 2 years and defined the sources of water in its tributes: 13 of them have atmospheric source and 9 – ground source. In general, isotopic content of water in the vicinity of Grønfjorden (mean values are: δ18O = −10,3 ‰, δD = −72,5 ‰) is higher than in other regions of Svalbard
