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Isotopic variations in the ice core of palsa and lithalsa
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.
Keywords: segregation ice formation, isotope fractionation, hydrogen isotopes, oxygen isotopes, lithalsa, palsa, permafrost, blister ice, north of Canada, Siberia
Article was received:02-04-2018
This article written in Russian. You can find full text of article in Russian here .