Iron isotopic systematics and ferric iron carriers of Phanerozoic continental red beds and implications for atmospheric oxygenation

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985831%3A_____%2F25%3A00638885" target="_blank" >RIV/67985831:_____/25:00638885 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/61989592:15310/25:73634446 RIV/00025798:_____/25:10169549

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S0009254125004188?dgcid=author" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0009254125004188?dgcid=author</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.chemgeo.2025.123028" target="_blank" >10.1016/j.chemgeo.2025.123028</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Iron isotopic systematics and ferric iron carriers of Phanerozoic continental red beds and implications for atmospheric oxygenation

Popis výsledku v původním jazyce

Continental red beds (CRB) are characteristic for their predominant red colour due to the widespread presence of ferric oxides (hematite or goethite) that might suggest distinctly oxygenated atmospheric conditions during their formation. Therefore, elemental and isotopic systematics of iron, a redox-sensitive element, can provide critical constraints on Fe cycling and possibly also palaeoredox conditions. However, our knowledge of the iron isotopic systematics (δ56Fe) of CRB remains very limited. This prevents to evaluate whether these rocks are useful to trace past atmospheric oxygenation. To fill the gap, we present an extensive dataset of Fe elemental and isotopic data, paralleled by Mössbauer and diffuse reflectance spectra, for classic Phanerozoic examples of CRB supplemented by the analyses of colour detrital grain coatings. The data reveal goethite as the principal phase within grey-green siliciclastic lithologies and detrital grain coatings. These samples show a positive correlation between Fe3+/FeT and δ56Fe (fine-grained lithologies) suggesting percolation of late-stage diagenetic fluids at variable redox and pH conditions connected with hematite dissolution. In contrast, the red facies are characterized by the predominance of hematite, largely variable FeT contents and δ56Fe values overlapping with those estimated for the upper continental crust. The overall lighter and more homogeneous δ56Fe values in Phanerozoic red beds compared to their Palaeoproterozoic (∼2.2 Ga) counterparts are consistent with more oxygenated atmosphere during the Phanerozoic. Therefore, the appearance of CRB may serve as an important marker of atmospheric oxygenation in the past.

Název v anglickém jazyce

Iron isotopic systematics and ferric iron carriers of Phanerozoic continental red beds and implications for atmospheric oxygenation

Popis výsledku anglicky

Continental red beds (CRB) are characteristic for their predominant red colour due to the widespread presence of ferric oxides (hematite or goethite) that might suggest distinctly oxygenated atmospheric conditions during their formation. Therefore, elemental and isotopic systematics of iron, a redox-sensitive element, can provide critical constraints on Fe cycling and possibly also palaeoredox conditions. However, our knowledge of the iron isotopic systematics (δ56Fe) of CRB remains very limited. This prevents to evaluate whether these rocks are useful to trace past atmospheric oxygenation. To fill the gap, we present an extensive dataset of Fe elemental and isotopic data, paralleled by Mössbauer and diffuse reflectance spectra, for classic Phanerozoic examples of CRB supplemented by the analyses of colour detrital grain coatings. The data reveal goethite as the principal phase within grey-green siliciclastic lithologies and detrital grain coatings. These samples show a positive correlation between Fe3+/FeT and δ56Fe (fine-grained lithologies) suggesting percolation of late-stage diagenetic fluids at variable redox and pH conditions connected with hematite dissolution. In contrast, the red facies are characterized by the predominance of hematite, largely variable FeT contents and δ56Fe values overlapping with those estimated for the upper continental crust. The overall lighter and more homogeneous δ56Fe values in Phanerozoic red beds compared to their Palaeoproterozoic (∼2.2 Ga) counterparts are consistent with more oxygenated atmosphere during the Phanerozoic. Therefore, the appearance of CRB may serve as an important marker of atmospheric oxygenation in the past.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10505 - Geology

Projekt

<a href="/cs/project/GA22-15405S" target="_blank" >GA22-15405S: Raně diagenetická mobilita geochemických indikátorů redoxních podmínek a paleoklimatologický význam kontinentálních červených vrstev</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2025

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Chemical Geology

ISSN

0009-2541

e-ISSN

1872-6836

Svazek periodika

695

Číslo periodika v rámci svazku

November

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

16

Strana od-do

123028

Kód UT WoS článku

001583395000001

EID výsledku v databázi Scopus

2-s2.0-105015539586