Formation of Ediacaran stromatolitic cherts through a combination of biogenic and abiotic processes: New insights from the Bohemian Massif

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985831%3A_____%2F24%3A00584913" target="_blank" >RIV/67985831:_____/24:00584913 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/00025798:_____/24:10169155 RIV/00216208:11310/24:10492202

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S0301926824000780" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0301926824000780</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.precamres.2024.107365" target="_blank" >10.1016/j.precamres.2024.107365</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Formation of Ediacaran stromatolitic cherts through a combination of biogenic and abiotic processes: New insights from the Bohemian Massif

Popis výsledku v původním jazyce

Stromatolites are remarkable organosedimentary laminated structures that grow gradually through time due to the activity of microorganisms, mostly algae and cyanobacteria. The appearance of stromatolites in formations as old as ∼ 3.7 Ga represents the earliest macroscopic traces of life on Earth. Yet, the biogenic origin of some presumed stromatolites has been questioned as abiotic processes (e.g., fluid precipitation, diagenesis and metamorphism) can also be responsible for the formation of stromatolite-like textures. This is especially true in case of pervasively silicified stromatolites (stromatolitic cherts) that have rarely been reported from Neoproterozoic successions. Here, we present a detailed study of the Ediacaran stromatolitic cherts from the Blovice accretionary complex (Bohemian Massif) that combines petrography, trace element and Si–O isotopic compositions and Raman spectroscopy of organic matter to decipher the complex processes leading to their formation and evaluate the biogenicity of their precursor. Textural evidence (i.e. the presence of pseudomorphs after carbonate/evaporate and micro-ooids, variable thickness and spacing of organic-rich laminae) as well as trace element/isotopic compositions argue for a multi-stage formation of stromatolitic cherts. The primary carbonaceous stromatolitic precursors first formed in shallow-water lagoons with variable salinity at seamount slopes, were then fragmented by surface processes (erosion, mass wasting), and finally silicified by low-temperature hydrothermal fluids. The primary biogenic character of stromatolitic textures is evidenced by the non-equidistant alternation of dark (organic matter-rich) and light laminae with markedly different oxygen isotopic compositions reflecting probably seasonal cycles during stromatolite deposition, enrichment of bio-essential elements (e.g., Cu, Zn, Co and Mn) in dark laminae, and Raman spectra of organic matter indicative for variably matured kerogens. The presence of late-stage diagenetic modifications might be related to subsequent burial and low-grade metamorphism of stromatolitic cherts within the accretionary wedge.

Název v anglickém jazyce

Formation of Ediacaran stromatolitic cherts through a combination of biogenic and abiotic processes: New insights from the Bohemian Massif

Popis výsledku anglicky

Stromatolites are remarkable organosedimentary laminated structures that grow gradually through time due to the activity of microorganisms, mostly algae and cyanobacteria. The appearance of stromatolites in formations as old as ∼ 3.7 Ga represents the earliest macroscopic traces of life on Earth. Yet, the biogenic origin of some presumed stromatolites has been questioned as abiotic processes (e.g., fluid precipitation, diagenesis and metamorphism) can also be responsible for the formation of stromatolite-like textures. This is especially true in case of pervasively silicified stromatolites (stromatolitic cherts) that have rarely been reported from Neoproterozoic successions. Here, we present a detailed study of the Ediacaran stromatolitic cherts from the Blovice accretionary complex (Bohemian Massif) that combines petrography, trace element and Si–O isotopic compositions and Raman spectroscopy of organic matter to decipher the complex processes leading to their formation and evaluate the biogenicity of their precursor. Textural evidence (i.e. the presence of pseudomorphs after carbonate/evaporate and micro-ooids, variable thickness and spacing of organic-rich laminae) as well as trace element/isotopic compositions argue for a multi-stage formation of stromatolitic cherts. The primary carbonaceous stromatolitic precursors first formed in shallow-water lagoons with variable salinity at seamount slopes, were then fragmented by surface processes (erosion, mass wasting), and finally silicified by low-temperature hydrothermal fluids. The primary biogenic character of stromatolitic textures is evidenced by the non-equidistant alternation of dark (organic matter-rich) and light laminae with markedly different oxygen isotopic compositions reflecting probably seasonal cycles during stromatolite deposition, enrichment of bio-essential elements (e.g., Cu, Zn, Co and Mn) in dark laminae, and Raman spectra of organic matter indicative for variably matured kerogens. The presence of late-stage diagenetic modifications might be related to subsequent burial and low-grade metamorphism of stromatolitic cherts within the accretionary wedge.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10505 - Geology

Projekt

<a href="/cs/project/GA20-13644S" target="_blank" >GA20-13644S: Silicity a karbonáty jako geochemické indikátory vzniku stratigrafie oceánských desek a paleoenvironmentálních změn</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2024

Kód důvěrnosti údajů

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

Název periodika

Precambrian Research

ISSN

0301-9268

e-ISSN

1872-7433

Svazek periodika

405

Číslo periodika v rámci svazku

June 2024

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

14

Strana od-do

107365

Kód UT WoS článku

001224042700001

EID výsledku v databázi Scopus

2-s2.0-85189509490