- Tytuł:
-
Mikrokonkrecje syderytowe w holoceńskich osadach ujścia rzeki Gwadiana w Portugalii : raport wstępny
Micro-scale sideritic concretions in Holocene sediments in the Guadiana estuary, Portugal : a preliminary report - Autorzy:
-
Wilamowski, A.
Boski, T.
Moura, D. - Powiązania:
- https://bibliotekanauki.pl/articles/2075017.pdf
- Data publikacji:
- 2013
- Wydawca:
- Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
- Tematy:
-
siderite
concretions
estuarine sediment
Guadiana River
Holocene
syderyt
konkrecje
sedymentacja osadów
rzeka Gwadiana
holocen - Opis:
- The authors described micro-scale carbonate concretions occurring at a depth of about 41 m within Holocene sandy sediments filling the Guadiana River paleovalley, representing the transitional fluvial- -estuarine facies. Despite their minute sizes, the micro-concretions show a complex internal structure. Regular distribution of Mg, Mn and Ca can be assigned to a chemical zoning, pointing to precipitation under varying chemical conditions. Based on morphological and chemical peculiarities, four types of concretions can be distinguished. Detrital Fe-Mg-carbonates form nuclei. At first, Mn-rich carbonate precipitated as a coating, which is coherent with the sequence of precipitation of carbonates associated with bacteria-mediated oxidation of organic matter. Subsequently, the main bodies of concretions precipitated as Fe-carbonate (siderite). The last precipitation episode is marked by enrichment in Ca. The XRD patterns show the presence of a mixture of discrete carbonate phases.
- Źródło:
-
Przegląd Geologiczny; 2013, 61, 10; 568--575
0033-2151 - Pojawia się w:
- Przegląd Geologiczny
- Dostawca treści:
- Biblioteka Nauki
Artykuł