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Wyszukujesz frazę "alkaline complex" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
The Tajno ultramafic-alkaline-carbonatite massif, NE Poland : a review. Geophysics, petrology, geochronology and isotopic signature
Autorzy:
Wiszniewska, Janina
Petecki, Zdzisław
Krzemińska, Ewa
Grabarczyk, Anna
Demaiffe, Daniel
Powiązania:
https://bibliotekanauki.pl/articles/2059668.pdf
Data publikacji:
2020
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Tajno intrusion
East European Craton
ultramafic complex
alkaline complex
carbonatitic complex
Carboniferous
Opis:
This paper reviews all available geological data on the Tajno Massif that intruded the Paleoproterozoic crystalline basement of NE Poland (Mazowsze Domain) north of the Teisseyre-Tornquist Zone, on the East European Craton. This massif (and the nearby Ełk and Pisz intrusions) occurs beneath a thick Mesozoic-Cenozoic sedimentary cover. It has first been recognized by geophysical (magnetic and gravity) investigations, then by drilling (12 boreholes down to 1800 m). The main rock types identified (clinopyroxenites, syenites, carbonatites cut by later multiphase volcanic/subvolcanic dykes) allow characterizing this massif as a differentiated ultramafic, alkaline and carbonatite complex, quite comparable to the numerous massifs of the Late Devonian Kola Province of NW Russia. Recent geochronological data (U-Pb on zircon from an albitite and Re-Os on pyrrhotite from a carbonatite) indicate that the massif was emplaced at ~348 Ma (Early Carboniferous). All the rocks, but more specifically the carbonatites, are enriched in Sr, Ba and LREE, like many carbonatites worldwide, but depleted in high field strength elements (Ti, Nb, Ta, Zr). The initial87Sr/86Sr (0.70370 to 0.70380) and ɛNd(t) (+3.3 to +0.7) isotopic compositions of carbonatites plot in the depleted quadrant of the Nd-Sr diagram, close to the “FOcal ZOne” deep mantle domain. The Pb isotopic data (206Pb/204Pb <18.50) do not point to an HIMU (high U/Pb) source. The ranges of C and O stable isotopic compositions of the carbonatites are quite large; some data plot in (or close to) the “Primary Igneous Carbonatite” box, while others extend to much higher, typically crustal ẟ18O and ẟ13C values.
Źródło:
Geological Quarterly; 2020, 64, 2; 402--421
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Colluvic umbrisols as a result of the erosion process of rolling and hilly country in agricultural area
Autorzy:
Braun, Barbara
Miłaszewska, Małgorzata
Powiązania:
https://bibliotekanauki.pl/articles/2034220.pdf
Data publikacji:
2010-06-01
Wydawca:
Uniwersytet Warszawski. Wydział Geografii i Studiów Regionalnych
Tematy:
Colluvic Umbrisols
thickness of the humus horizon
fractional composition of humus
reaction
dehydration of the sorption complex by alkaline ions
Opis:
Agricultural activity, especially agricultural mechanization, leads to acceleration of erosion in rolling and hilly country. The level of the erosion process, already during territorial observations, may be assessed by the thickness of the humus horizon. In the vicinity of Bytów, the deluvial humus horizons have even achieved thickness of 100 cm. These horizons are also richer in organic matter than humus horizons located on flat-topped mountains and mountain sides. Deluvial horizons are characterized by a somewhat less acid reaction, sometimes even neutral, and somewhat greater dehydration of the sorption complex by alkaline cations.
Źródło:
Miscellanea Geographica. Regional Studies on Development; 2010, 14; 213-219
0867-6046
2084-6118
Pojawia się w:
Miscellanea Geographica. Regional Studies on Development
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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