2021
Redox geochemistry of the red ‘orthoceratite limestone’ of Baltoscandia: Possible linkage to mid-Ordovician palaeoceanographic changes
BÁBEK, Ondřej, Tomáš KUMPAN, Mikael CALNER, Daniel ŠIMÍČEK, Jiří FRÝDA et. al.Základní údaje
Originální název
Redox geochemistry of the red ‘orthoceratite limestone’ of Baltoscandia: Possible linkage to mid-Ordovician palaeoceanographic changes
Autoři
BÁBEK, Ondřej (garant), Tomáš KUMPAN (203 Česká republika, domácí), Mikael CALNER, Daniel ŠIMÍČEK, Jiří FRÝDA, Markéta HOLÁ (203 Česká republika, domácí), Lukáš ACKERMAN a Kateřina KOLKOVÁ
Vydání
Sedimentary Geology, Elsevier B.V. 2021, 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: 3.329
Kód RIV
RIV/00216224:14310/21:00119061
Organizační jednotka
Přírodovědecká fakulta
UT WoS
000659165600010
Klíčová slova anglicky
Marine red beds; Early diagenesis; Redox gradients; Laser ablation ICP-MS; Sea-level changes; Carbon isotope geochemistry
Štítky
Příznaky
Mezinárodní význam, Recenzováno
Změněno: 21. 2. 2023 13:27, Mgr. Marie Šípková, DiS.
Anotace
V originále
The orthoceratite limestone of the Ordovician epicontinental sea of Baltoscandia is one of the oldest Phanerozoic examples of pelagic marine red beds (MRBs). Being enriched in authigenic haematite, MRBs are considered to be sensitive palaeoceanographic redox indicators. In this paper, the origin of the reddening of the Ordovician MRBs and its timing and redox conditions were addressed at two sections, and in a drill core in the Kinnekulle area, Sweden, through the application of diffuse reflectance spectroscopy, sedimentary petrology (microfacies and electron microprobe), bulk-rock and in-situ element geochemistry (laser-ablation ICP-MS) and molybdenum stable isotope systematics. Enrichment in haematite (up to ~0.05 wt%) occurred during very early diagenesis under low sedimentation rates (~5 mm/kyr), which is comparable to several examples of Phanerozoic MRBs. The reddening was associated with the mm-scale, in-situ mobility of Fe, Mn, As, Mo and U, due to Fe–Mn redox cycling between primary and secondary minerals and pore water under oxic and suboxic to anoxic conditions; it was not related to significant changes in seawater chemistry. Stratigraphic red-to-grey transitions likely coincided with two mid-Darriwilian global regressions (the so-called Täljsten and at the base of the Gullhögen Formation), likely due to the effects of changing sedimentation rates and sub-bottom redox potentials. The Ordovician MRBs coincided with a positive δ13C excursion during the middle Darriwilian, which is different to MRB examples cited from the Devonian to the Cretaceous age, which frequently coincide with shifts to lower values of δ13C. Although MRBs are believed to show a time-specific occurrence in greenhouse or transitional greenhouse-to-icehouse climatic modes by several authors, our study suggests that causal links between MRBs and global carbon cycle remain unclear.
Návaznosti
GA19-17435S, projekt VaV |
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