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Wyszukujesz frazę "deep-sea sediments" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
Geochemistry of surface sediments from the northwestern Gulf of Mexico : implications for provenance and heavy metal contamination
Autorzy:
Armstrong-Altrin, John S.
Botello, Alfonso V.
Villanueva, Susana F.
Soto, Luis A.
Powiązania:
https://bibliotekanauki.pl/articles/2058576.pdf
Data publikacji:
2019
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Tamaulipas
deep-sea sediments
enrichment factor
contamination
principle component analysis
Opis:
Thirty-five near-surface sediment samples were recovered from the continental shelf and upper slope regions of the north-western (NW) Gulf of Mexico. The geochemical data of the sediments recovered were examined to investigate the weathering intensity, provenance, palaeo-oxygenation condition, and level of heavy metal contamination. The sediments analysed showed a moderate to high intensity of chemical weathering. Major and trace element concentrations indicated a terrigenous origin, closely related to the weathering of rocks rich in aluminosilicates. The results of this study further revealed that major rivers, the Bravo and Soto La Marina, played an important role in delivering sediments to the study area. The concentration of transition trace elements such as Cr, Cu, Ni, and V revealed that the sediments were derived from intermediate rocks such as andesite. The V/Cr, Ni/Co, and Cu/Zn ratios in the sediments were <2, <5, and <1, respectively, suggesting a depositional process occurred under well-oxygenated conditions. Principle Component Analysis (PCA) did not show a significant difference in sediment texture between the continental shelf and slope areas. The enrichment factor (EF) and Geo-accumulation index (lgeo) values were <2 and <1, respectively, suggesting the absence of an anthropogenic input.
Źródło:
Geological Quarterly; 2019, 63, 3; 522--538
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A framework of ichthyofaunal ecostratigraphy of the Oligocene-Early Miocene strata of the Polish Outer Carpathian basin
Podstawy ekostratygrafii ichtiofaunistycznej osadów oligocenu-wczesnego miocenu basenu zewnętrznych Karpat Polskich
Autorzy:
Kotlarczyk, J.
Jerzmańska, A.
Świdnicka, E.
Wiszniowska, T.
Powiązania:
https://bibliotekanauki.pl/articles/191627.pdf
Data publikacji:
2006
Wydawca:
Polskie Towarzystwo Geologiczne
Tematy:
fossil fish collection
Teleostei
deep-sea sediments
lithostratigraphy
biostratigraphy
fish ecoassemblages
models of changes
ichthyofaunal zonation
ecostratigraphy
Oligocene
Early Miocene
Outer Carpathians
Polska
Opis:
The paper presents the results of an analysis of ichthyofaunal variability throughout the section of the Menilite-Krosno Series (MKS) in the Outer Carpathians of Poland. The studied tanathocoenoses were formed at the bottom of a more than 2,000 m deep northern basin of the Tethys, being largely represented by the continental rise and bottoms of its narrow furrows, and - to a lesser degree - the continental slope and slopes of a submarine high. Lateral variability of statististically representative assemblages of tanathocoenoses hosted in thin, isochro- nous horizons is interpreted as a result of both local changes of ichthyocoenoses and the influence of post-mortem relocation of fishes that mainly dwelled the shelf and upper continental slope. Vertical variability, in turn, is considered as a resulting from changeable conditions of the ecological environment, the input and outflow of taxa whose evolution proceeded in the Indo-Pacific area, and the species extinction. Changeability of ichthyofauna within a ca. 16-m.y.-long interval made it possible to document and formally describe 9 zones and 4 subzones of ichthyofauna of ecostratigraphic character. These zones comprise index, representative and accompanying taxa that belong to different ecological groups. Conceptual models of the origin of ichthyofaunal assemblages of individual zones are presented. It is suggested that the origin of assemblage differentiation resulted from the appearance and disappearance of the oxygen minimum zone in the water column, global and local sea level changes, topography of the basin bottom, as well as final basin infilling by sediments of submarine fans. The described and preserved collection of fossil Carpathian fishes, housed at the Department of Palaeozoology of the University of Wrocław, requires further specialized palaeontological studies in order to reconstruct a more complete composition of the Oligocene-Early Miocene ichthyofauna.
Źródło:
Annales Societatis Geologorum Poloniae; 2006, 76, No 1; 1-111
0208-9068
Pojawia się w:
Annales Societatis Geologorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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