DOI: 10.7256/2453-8922.2018.1.25910

Abstract: Frozen mounds are the object of the study, the formation of which is associated with segregation of ice and moisture migration to the freezing front. Two varieties are considered as follows: typical palsa in the peat bogs, and lithalsa – ice-mineral (and sometimes mineral-ice) mounds in mineral dispersed sediments. A review of the isotopic composition of seasonal and perennial frozen mounds is presented. Three main sources of water for lithalsa and palsa are distinguished. The main research method is the analysis of oxygen and hydrogen isotopic composition of the ice cores of the lithalsa and palsa. The new results of the study are as follows: a) the isotope composition of the segregated ice of the palsa and lithalsa cores is usually quite homogeneous: variations in oxygen rarely exceed 2-3‰; b) there is a definite correspondence between the isotopic composition of the ice of the palsa and lithalsa and the isotopic composition of the water of surrounding bog is lighter by 2-3‰; this is a result of fractionation during the freezing of the bog waters; c) comparison of the isotopic composition in the segregated ice of the palsa and lithalsa, atmospheric, surface and boggy waters revealed a close isotope-oxygen and isotope-hydrogen composition of them.

DOI: 10.7256/2453-8922.2018.1.25833

Abstract: The objects of this research is the massive ice beddings in the valley Mordyakha River valley, as well as the terrace of Seyakha River (Mutnaya) in the central part of Yamal Peninsula. First of the studied ice bedding outcrops is located the center of Yamal Peninsula, in the upper reaches of Mordyakha (68°11ʹ18ʺN, 68°51ʹ39ʺE), at absolute elevation of 66-70 m; the second one (70°23.4 N, 68°19.4 E) is located 0.6 km towards southwest of the field base GP-1 Bovanenkovo deposit and 5 km towards northwest of Bovanenkovo settlement, at absolute elevation of 87 m. The authors meticulously examine the structure of bedded deposits and peculiarities of their contacts with the enclosing rocks. The article studies the concentration of stable isotopes of oxygen and hydrogen in ice, composition of the main anions and cations, as well spore-pollen remains within ice. The following conclusions were made: a) the studied bedded deposits are classifies as intra-ground type; b) one of the main water source that formed massive ice were lake waters and talik water ; c) in the process of ice formation took place a significant isotope fractionation, which led to the formation of layers with isotope composition heavier than the original lake waters.

DOI: 10.7256/2453-8922.2018.1.25857

Abstract: The object of this study is the ice wedges of Holocene age on the western coast of the Baydarata Bay, at the mouth of the Ngarka-Tambyakha River. In the coastal cliff structure of the thin polygonal peatland have been studied. The peatland is located in the upper part of the terrace 8-17 m high. The peat is underlain by gray icy loam with layered-lenticular cryogenic structure. Ice wedges revealed at the depth 0.8 m. Their width was 1.5-2 m, and outcropped height about 1.15 m high. One representative ice wedge was sampled across horizontal axis in the upper part, 9 samples were analyzed on a mass spectrometer, the oxygen isotope and hydrogen isotope composition of ice wedges was obtained. The main conclusions are: harsh winter air temperature in the area in Holocene varied between –16 and –19° С, which is about 10°С warmer compared to Late Pleistocene and were close to modern ones. Obtained results complement sparse information on Holocene winter air temperature for the Baydarata Bay coast.

DOI: 10.7256/2453-8922.2018.1.25871

Abstract:   The object of this research is the most southern massive ice in the Yamal Peninsula, located on the left bank of the Erkutayakha River (68°11ʹ18ʺ N, 68°51ʹ39ʺ E). A dislocated ice massif occurred in the 15-18 m exposure of the sandy layer. Its total length is about 100 m. The ice massif is composed of different types of ice. There are four types of ice: 1) pure matte white ice with a large number of gas xenogenic inclusions; 2) crystal clear ice, sometimes with soil inclusions; 3) gray ice with a steel tint, layered parallel to the slope of the upper surface of the massive ice; 4) gray block-ice, lies in the form of tiles. Each type of the ice was examined, and 10 samples of ice from different parts of the outcrops and of ice of different types have been selected for pollen study. The results of this study allowed more adequately evaluating the origin of the ice.  

DOI: 10.7256/2453-8922.2018.1.25949

Abstract: The outcrop of 7-m terrace in the mouth of Gyda River (70°53ʹ41ʺ N. 78°30ʹ14ʺ E) is the object of the study. There are two generations of ice wedges and four stages of ice lens occurred in peaty sand. Syngenetic ice wedges are in paragenesis with massive ice. Considerable reworking of organic material is proved. Seven cycles of vegetation changes corresponded to local pollen zones. Their duration is about 0.5-2 ka. Sediments accumulated at alternation of subaerial and subaueous stages in 3-13 ka BP.Ice wdges accumulated at the end of the Late Pleistocene in 11-12 ka BP and in the Holocenein 3-4 ka BP. The total annual thawing index variated from 200 to 800 oC x day

DOI: 10.7256/2453-8922.2018.1.25935

Abstract: The object of the study are ice-mineral permafrost mounds (lithalsas) in the valley of the Sentsa River in the Eastern Sayan Mountains (52º39.827' N, 99º29.858' E). The aim of the research is to study the internal structure of the mounds and, in particular, the depth of occurrence of ice lenses. The article examines the magnetic susceptibility of alluvial soils and entic podzols to determine the intensity of Fe illuvial process. The content of organic carbon and iron in soils was measured. Electromagnetic prospecting was performed using a symmetric four-electrode Schlumberger installation using a set of ASTRA-100 (generator) and MERI-24 (measuring instrument). The magnetic susceptibility of the soil was measured using a portable magnetic susceptibility meter PIMV-M over a uniform grid of 20 cm. The total content of Fe in soils was measured by ICP-MS. It was established that the ice lenses are located at depths of about 4 meters and have a vertical thickness of 10 meters. The presence of two separate ice lenses in the largest of the studied mounds was established. Magnetometry confirmed the high intensity of the Fe illuvial process in lithalsa soils. Ground squirrels inhabiting this area create places for the accumulation of iron compounds.

DOI: 10.7256/2453-8922.2018.1.25936

Abstract: The article deals with the problems of arranging pile foundations on the territory of the Republic of Sakha (Yakutia) using bored piling. This technology, which is not so widespread in the republic, is simpler and more convenient, in contrast to reinforced concrete foundation piles. In the process of hardening concrete during the arrangement of the bored pile, local fission of frozen soil occurs. Therefore, when using bored piles in the cryolithozone, the problem of determining the design temperatures and the time of formation of the stationary soil regime at the base of the entire pile field, which allows full loading of the foundations, becomes especially critical. Field observations of the temperature regime of soils near the bored pile during its arrangement and hydration of concrete were carried out. In the course of the study, data was obtained on the dynamics of the temperature regime of the soil near the bored pile in the process of its arrangement. The data obtained show that stable negative temperatures over the entire depth of the well are observed one month after pouring, during which period the pile attains most of its strength.