Geochemical Features of Ground Ice from the Faddeevsky  Peninsula Eastern Coast (Kotelny Island, East Siberian Arctic) as a Key to Understand Paleoenvironmental Conditions of Its Formation

Pismeniuk, A.; Semenov, P.; Veremeeva, A.; He, W.; Kozachek, A.; Malyshev, S.; Shatrova, E.; Lodochnikova, A.; Streletskaya, I.

Авторы: Pismeniuk Anfisa, Semenov Petr, Veremeeva Alexandra, He Wei, Kozachek Anna, Malyshev Sergei, Shatrova Elizaveta, Lodochnikova Anastasiia, Streletskaya Irina
Журнал: LAND
Год издания: 2023
Первая страница: 1
Последняя страница: 25
DOI: 10.3390/land12020324
Аннотация: Understanding paleoenvironmental conditions of the permafrost formation allows us to estimate the permafrost carbon pool and its behavior upon thawing in a changing climate. In order to classify different types of ground ice and to reconstruct paleoenvironments, we examined geo-chemical data of ice wedges (IWs), tabular ground ice (TGI), and lens ice from the eastern coast of the Faddeevsky Peninsula (East Siberian Arctic). We analyzed isotope and ion composition, mo-lecular composition of the gas phase, bulk biogeochemical parameters and dissolved organic matter (DOM) composition in ground ice samples. IWs formed in the Late Pleistocene under the coldest winter conditions and in the Holocene in proximity to the sea. The Holocene IWs have the highest mean d-excess (11–13‰) and a heavier isotope composition by an average of 6‰ com-pared with the Late Pleistocene IWs. We observe predominance of sea-salt fractions in ion composition of the Holocene IWs, while the Late Pleistocene IW shows enrichment in non-sea-salt component of SO42- (nssSO42-), which is probably associated with mineral leaching of deposits. Higher dissolved organic carbon (DOC) content in the Late Pleistocene IW (to 17,7 mg/L) may indicate more favorable vegetation conditions or lower degree of organic matter mineralization compared to Holocene IWs and TGI. CH4 concentrations were relatively low with a maximum value of 2.27 μmol/L. DOM composition, supposed to record the paleoenvironment of the freezing process, was for the first time tried as a biomarker for paleoenvironmental reconstructions of ground ice formation. Parallel factor (PARAFAC) analysis of EEM (Excitation-Emission matrix) of fluorescent DOM decomposes four components: P1–P3, which are related to allochthonous humiс-like constituents, and P4, which is relevant to autochthonous fraction associated with microbial activity. The distribution of fluorescent DOM tracked the variability in both paleoclimate conditions of the IW formation (discriminating the Holocene and the Late Pleistocene IWs) and types of ground ice (IW and TGI), which demonstrates the potential of the used approach.
Добавил в систему: Стрелецкая Ирина Дмитриевна

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Geochemical Features of Ground Ice from the Faddeevsky Peninsula Eastern Coast (Kotelny Island, East Siberian Arctic) as a Key to Understand Paleoenvironmental Conditions of Its Formationстатья

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