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Conditions of development of structural relief in crystalline rocks (case study: Murmansk Upland and Kandalaksha region, Kola Peninsula, Russia)

Superson W., Huber M., Zgłobicki W.

Landform Analysis

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2013

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Vol. 22

103--109

EN

Structural relief is exceptionally recognisable in areas where igneous and metamorphic rocks without a Quaternary cover occur, which is the case with the Kola Peninsula. However, the subject of structural relief has been addressed relatively rarely. Therefore, an attempt was made to estimate the influence of tectonic and lithologic factors on the relief within two test areas, each covering approximately 100 km2, located on the coast of the Barents Sea (Murmansk Terrane) and the White Sea (Lapland Granulite Belt). The structural relief here is varied, which results from differences in the geological structure. In the former area, depressions and tectonic blocks of varying size and order predominate, while east of Kandalaksha these are flattened hills with asymmetrically inclined slopes (having the character of cuestas). Although lithologically diverse, the test areas share a common feature: the presence of numerous faults and dislocation zones that in the case of the Barents Sea caused the division of igneous rocks into several blocks of various orders. Most of the relief forms in this area were found to have structural origins, namely valley depressions of various orders, slopes and escarpments, lake basins and seaside cliffs. The structural relief of the Murmansk Terrane is determined by disjunctive structures. In the case of the Lapland Granulite Belt, the relief of the analysed macroblock is closely linked with the formation and position of the rocks – this is escarpment relief.

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REE and Sr-Nd Isotope Compositions of Clinopyroxenites, Phoscorites and Carbonatites of the Seblyavr Massif, Kola Peninsula, Russia

Balaganskaya Elena, Downes Hilary, Demaiffe Daniel

Mineralogia

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2007

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Vol. 38, iss. 1

29--45

EN

Clinopyroxenites, phoscorites and carbonatites from the Devonian Seblyavr intrusion (Kola Peninsula, Russia) have petrographic characteristics indicating that they are accumulative in origin. Their geochemical (major and rare earth elements) compositions can be accounted for by mixtures of their major rock-forming minerals and accessory phases, i.e. they reflect the record of mineral accumulation. All of the analysed Seblyavr rocks are strongly LREE-enriched with (La/Yb)N mostly ranging from 38 to 189. However, a dolomite carbonatite with hydrothermal LREE-Sr mineralization has an extreme (La/Yb)N value of 1659. Such late-stage dolomite carbonatites were formed by hydrothermal (rather than magmatic) processes. Whole-rock samples of representative magmatic lithologies from Seblyavr have initial 87Sr/86Sr and εNd that fall in a very narrow range from 0.7031 to 0.7033 and +4.9 to +5.9, respectively. We therefore conclude that clinopyroxenites, phoscorites and carbonatites were formed by differentiation and crystallization of a single batch of melt. The parental melt was derived from a depleted upper mantle source that had been meta-somatised prior to melting.

PL

Petrograficzna charakterystyka dewońskich klinopiroksenitów, foskorytów i karbonatytów z masywu sebliawrskiego na Półwyspie Kola (Rosja) wskazuje, że skały te są kumulatami. Ich skład chemiczny (zarówno pierwiastki główne jak i pierwiastki ziem rzadkich) stanowi zapis procesów akumulacyjnych i wynika ze zmieszania głównych minerałów skałotwórczych i faz akcesorycznych. Wszystkie analizowane skały masywu sebliawrskiego są silnie wzbogacone w LREE, a ich stosunek (La/Yb)N waha się przeważnie pomiędzy 38 a 189. Skrajnie wysoki stosunek (La/Yb)N równy 1659 zanotowano w dolomitowym karbonatycie, zawierającym hydrotermalną mineralizację LREE-Sr. Takie karbonatyty zostały utworzone w końcowych etapach powstawania masywu dzięki właśnie procesom hydrotermalnym, a nie magmowym. Próbki reprezentujące skały magmowe masywu wykazują początkowe stosunki izotopów strontu 87Sr/86Sr i wartości parametru Nd zawarte w wąskich przedziałach, odpowiednio od 0,7031 do 0,7033 i od +4,9 do +5,9. Upoważnia to do sformułowania wniosku, że badane klinopiroksenity, foskoryty i karbonatyty utworzyły się w wyniku dyferencjacji i krystalizacji pojedynczej porcji stopu magmowego. Ten macierzysty stop został wygenerowany ze zubożonego górnego płaszcza, a źródłowy materiał uległ metasomatozie jeszcze przed momentem stopienia.

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Lithology and palaeomagnetic record of Late Weichselian varved clays from NW Russia

Bakhmutov V., Kolka V., Yevzerov V.

Geological Quarterly

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2006

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Vol. 50, No. 3

353-368

EN

A lithological and palaeomagnetic analysis of Late Weichselian glaciolacustrine deposits from two ancient periglacial lakes was carried out in the valley of the Shuja (S Karelia) and Ust-Pjalka (S-E Kola Peninsula) rivers, NW Russia. The rhythmic structure of the varved clays is interpreted as turbiditic with systematic differences between the proximal and distal areas of accumulation. In the proximal area the textural and structural properties of the deposits towards both distal and (partly) lateral directions are described. It is shown that the proximal varve successions are incomplete while distally they are continuous. The accumulation of one varve (DE rhythm, second order cycle) during one year is consistent with palaeomagnetic data. Significant differences in magnetic parameters and in the palaeomagnetic "records" of declination-inclination between proximal and distal varves are established. Analysis of palaeomagnetic properties was combined with lithological analysis in all sections. Locally, the varved clays in the proximal area could be used for palaeomagnetic research. Taking into account the erosion of underlying deposits by turbidity currents and inclination shallowing, these sediments could not precisely record palaeosecular variation (PSV). The distal varved clays (represented by the DE rhythms) are clearly most useful both for varve-clay chronology and PSV recovery. The palaeomagnetic declination and inclination records are correlated with chrono- and magnetostratigraphy scheme of NW Russia. This paper also examines lithology-dependent "inclination error" and anisotropy of magnetic susceptibility in glaciolacustrine sediments.

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Charakterystyka mineralogiczno-geochemiczna eudialitu z masywu Chibiny (Płw. Kolski, Rosja)

Natkaniec-Nowak L., Pitera H.

Przegląd Geologiczny

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2000

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Vol. 48, nr 12

1169-1173

PL

W pracy przedstawiono charakterystykę mineralogiczno-geochemiczna eudialitu z Chibin (Płw. Kolski) na tle innych światowych wystąpień tego minerału. Duże koncentracje eudialitu, spotykane najczęściej w ziarnistych skupieniach w lujawrytach, mogą być wykorzystane jako potencjalne źródło surowców radioaktywnych. Tezę tę potwierdziły wykonane badania fazowe. Na podstawie analiz chemicznych eudialitu stwierdza się, że minerał ten zawiera podwyższone koncentracje tlenków ZrOi, Na2O, CaO i MnO. Stwierdzono ponadto nieznaczne zmiany parametrów komórki elementarnej badanego eudialitu. Widmo absorpcyjne oraz obszerna jego interpretacja stanowi niewątpliwy przyczynek do poznania natury tego minerału.

EN

The paper presents the mineralogical and geochemical characteristic of eudialyte from Khibiny Massif (Kola Peninsula) with references to other occurrences of this mineral in the world. The large concentrations ofeudialyte usually found in granular form of luiavrite can be considered as potential sources of radioactive materials. This has been confirmed by the phase researches. The chemical analysis proved the presence of increased amounts ofZrO2, Na2O, CaO and MnO. Slight changes in basic cell parameters of tested eudialyte have been found additionally. The absorption spectrum of eudialyte shown in the paper and its interpretation should give better approach to our knowledge of the nature of this mineral.