Search

A sample found by geologists in 2002 in a forest near the village of Chelmuzhi (Medvezhyegorsky district of the Republic of Karelia) was examined. Unlike regional rocks, the sample had high hardness and strength, electrical conductivity, and weak magnetic properties. During its detailed study, Widmanstätten structure, chondrules, and iron-chromium-nickel alloy of matrix consisting mainly of taenite and cohenite, the grains of metals, their oxides, refractory perovskite, periclase, rutile, pyrochlore, corundum, and Ca, Al, and C inclusions were discovered. High contents of carbon and low content or complete absence of oxygen were recorded in some components of the sample. The hypotheses of the meteoritic and mantle origin of the sample are discussed. [ABSTRACT FROM AUTHOR]

The results of the comprehensive study (diatom and pollen and spore analysis, and 14С-dating) of Holocene bottom sediments from a lake on the shore of Kandalaksha Bay, White Sea, at the Keret' River mouth, are reported. Three stages in the evolution of the lake basin: marine, transitional, and lacustrine, were recognized. Diatom complexes, typical of each facies, were described. Pollen, spores and non-pollen palynomorphs were shown to indicate marine, transitional, and freshwater sedimentation conditions. Sea level was found to decrease 7200 cal. y.a. A marine sedimentation environment was succeeded by a lacustrine environment ca.6700 cal. y.a. The position of the sea shoreline in the study area at that time was determined. Data obtained by pollen and spore analysis were used for relative dating of postglacial strata. Vegetation, evolving from the end of the Early Holocene to the present, was reconstructed. [ABSTRACT FROM AUTHOR]

This paper reports on the lithological, micropaleontological, and chronometric data (radiocarbon dating) for one of the areas of the White Sea coast. The sedimentary sequences were studied in the current lake basins, which were separated from the large basin at different times. The basin was situated in the head of the current Onega Bay. On the basis of these data, the bottom sediments were stratified and the Late Pleistocene–Holocene paleogeographic settings were reconstructed for the southeastern part of Onega Bay. [ABSTRACT FROM AUTHOR]

Two specimens of lake diatomites of Karelia differing by the rock-forming types of diatoms and the form, size, and degree of preservation of the valves are investigated. It is determined that the size of the valves has a large effect on the granulometric composition and physical-chemical properties of diatomites. The SiO2 content in the initial samples of diatomites is 70%. After heat-treatment and leaching it increases to 91% and the iron content decreases sharply to 0.075%. After impurities have been removed, lake diatomites are of interest for the production of sheet glass, crystal articles, glazes and enamels, silicate glasses, as well as ceramic articles. [ABSTRACT FROM AUTHOR]