2022
Ferruginous coated grains of microbial origin from the Lower Devonian (Pragian) of the Prague Basin (Czech Republic) – Petrological and geochemical perspective
VODRÁŽKOVÁ, Stanislava, Tomáš KUMPAN, Radek VODRÁŽKA, Jiří FRÝDA, Renata ČOPJAKOVÁ et. al.Základní údaje
Originální název
Ferruginous coated grains of microbial origin from the Lower Devonian (Pragian) of the Prague Basin (Czech Republic) – Petrological and geochemical perspective
Autoři
VODRÁŽKOVÁ, Stanislava (garant), Tomáš KUMPAN (203 Česká republika, domácí), Radek VODRÁŽKA, Jiří FRÝDA, Renata ČOPJAKOVÁ (203 Česká republika, domácí), Magdalena KOUBOVÁ, Axel MUNNECKE, Jiří KALVODA (203 Česká republika, domácí) a Markéta HOLÁ (203 Česká republika, domácí)
Vydání
Sedimentary Geology, Amsterdam, Elsevier Science, 2022, 0037-0738
Další údaje
Jazyk
angličtina
Typ výsledku
Článek v odborném periodiku
Obor
10505 Geology
Stát vydavatele
Nizozemské království
Utajení
není předmětem státního či obchodního tajemství
Odkazy
Impakt faktor
Impact factor: 2.800
Kód RIV
RIV/00216224:14310/22:00126714
Organizační jednotka
Přírodovědecká fakulta
UT WoS
000830322900001
Klíčová slova anglicky
Ironstones; Microbialites; Trace elements geochemistry; REE geochemistry; Oncoids
Štítky
Příznaky
Mezinárodní význam, Recenzováno
Změněno: 20. 9. 2022 17:15, Mgr. Marie Šípková, DiS.
Anotace
V originále
A unique occurrence of ironstone lenses represented by ferruginous oncoids is reported from the offshore Iteporyje Limestone (Lower Devonian, Pragian) from the Prague Basin (the Stydle Vody Quarry). The oncoidal cortices show distinct arrangement of hematite/chamosite and/or iron-bearing calcite laminae, which are irregular, wavy and with a relatively high degree of inheritance of shape of the topography of the underlying laminae. Micro-domes and bulges, comparable to those observed in stromatolites and laminae overgrowing topographic irregularities represented by agglutinated foraminifers cemented to oncoid surfaces, were fairly commonly observed. The foraminifers probably represent the earliest representatives of agglutinated foraminifera encrusting surfaces of ferruginous grains. The surfaces of oncoids are wavy and often wrinkled. Although no microbial re-mains that could have been directly associated with oncoidal growth were recorded, we regard above mentioned features as indicators of biogenicity of the precipitates. We could only speculate the nature of the microbial consortia, but we regard the alternation of Fe2+ (chamosite, iron-bearing calcite) and Fe3+ (hematite) phases as a result of coupled oxidation -reduction processes related to passive and/or active microbial metabolic activities (precipitation of ferrihydrite - hematite precursor) and passive mineral authigenesis mediated by microorgan-isms (precipitation of chamosite precursor). Spatially restricted occurrence of the oncoidal lenses along with Al/Al + Fe + Mn vs. Fe/Ti, Nd vs. Ce/Ce*, Eu/Sm vs. Sm/Yb and other crossplots suggest that hydrothermal fluids were the most probable source of ferrous iron. Since most of the known oolitic or oncolitic ironstones represent rather large sedimentary bodies deposited around storm wave base to shallow subtidal environments under in-fluence of upwelled anoxic watermasses or continental runoff, the reported oncolitic mounds represent a specific example of ironstones formation.(C) 2022 Elsevier B.V. All rights reserved.
Návaznosti
GC20-20785J, projekt VaV |
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