Mineral and geochemical composition of the Onega Ice Lake sediments

Abstract

An analysis of the mineral-geochemical composition and structure of the Holocene–Pleistocene bottom sediments was performed on Lake Polevskoye, a small lake in the northern Lake Onega area in Russian Karelia, which is considered representative to describe the Late Weichselian Onega Ice Lake sediments. The analysis was accomplished using modern analytical methods, including scanning electron microscopy and ICP-MS, which allowed us to interpret their genesis in a new light. It is assumed that the distribution of rare earth elements (REE) in the bottom sediments of the recent Lake Onega and in the sediments of Onega Ice Lake will improve our understanding of the history of sedimentogenesis. It is apparent in the distribution of REE, their composition and data on the geochemical and mineral composition of the Holocene bottom sediments of Lake Onega and Lake Polevskoye (varved clays) that in their composition of terrigenous matter the material introduced from the north-western part of the catchment area is mainly composed of Archaean and Early Proterozoic crystalline complexes. However, the values of several indicator ratios of elements in the lower part of the of varved clays with shungite interlayers indicate the presence of mixing of clastic material from two sources of different geochemical origin: the north-western part of the catchment area (source of shungite rocks) and the south-eastern part of the catchment area (Phanerozoic sedimentary rocks of the Russian Platform).

Polish Polar Research

“…This is due to the influence of long-range atmospheric transport (Krachler et al 2006;McConnell et al 2019), which traditionally enriches the landscapes of the Republic of Karelia and neighbouring regions (Vinogradova et al 2017;Slukovskii et al 2020c). Increased accumulation of Cd, Zn, and Mo was noted in both the recent and the background sediments, which may be associated with the peculiarities of the natural level of these metals in the territory of Karelia, because earlier their increased concentrations were noted in the sediments of small lakes in this region and in the sediments of Lake Onega (Strakhovenko et al 2018;Slukovskii 2020;Slukovskii and Dauvalter2020). At the same time, it should be borne in mind that Cd is also an agent for the long-range transport of pollutants, and that its increased accumulation in the recent layers of sediments of lakes in northern Europe largely depends on this process.…”

“…The analysis of the chemical composition of water and recent sediments of the largest waterbodies in Europe is a significant component in assessing their current ecological state (Davydova et al 1999;Flerov et al 2000;Wihlborg and Danielsson 2006;Virkutyte et al 2008;Strakhovenko et al 2018). This is of great importance for both the fundamental science and the practical application of the knowledge gained, given that most of the large lakes are actively used for economic and recreational purposes, and serve as sources of drinking water for settlements.…”

Distribution of Elements in Iron-Manganese Formations in Bottom Sediments of Lake Onego (NW Russia) and Small Lakes (Shotozero and Surgubskoe) of Adjacent Territories

“…An analysis of the composition and geochemical features of upper bottom sediments of the cores Lake Onego (upper 0-50 cm of sediment) showed that they belong to two different types [38,39]. Well water circulation in the lake, which provides deep-water composition near the bottom (20 cm above the bottom sediment), is generally scarcely different from the contents of the whole water body in O 2 , N organic , P and Si across all bottom sediment stations, and Mn and Fe in the first type of bottom sediment stations.…”

“…During chemical composition analysis of FM nodules and crusts from these lakes, the constant presence of Ba and Fe in signifficant amounts in manganese zones was revealed, along with the presence of Mn and P impurities in the granular zones. The chemical composition of FM nodules from Lake Surgubskoe is as follows: granular zones (%): Fe (24-67), Mn (0-21), Ва (0-0.5), O (28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42), Р (0.5-2), and total (44-100); manganese zones (%): Fe (1-35), Mn (38)(39)(40)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52), Ва (4-12), O , Р (0-1), and total (55-99).…”

“…The chemical composition of FM crusts from Lake Shotozero is as follows: iron zones (%): Fe (37-58), Mn (0-6), Ва (0), O (28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39), Р (0.5-2), and total (72-100); manganese zones (%): Fe (0-3), Mn (33-55), Ва (1-8), O (30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42), Р (0), and total (56-99). The chemical composition of FM nodules from Lake Shotozero is as follows: granular zones (%): Fe (33-51), Mn (0-2), Ва (0), O (28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39), Р (0.5-1), and total (61-96); manganese zones (%): Fe (0-20), Mn (33-56), Ва (1-8), O (26)(27)(28)(29)(30)(31)(32)(33)(34)…”