Elemental and isotopic compositions of trench-slope black shales, Bohemian Massif, with implications for oceanic and atmospheric oxygenation in early Cambrian

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00025798%3A_____%2F21%3A00000046" target="_blank" >RIV/00025798:_____/21:00000046 - isvavai.cz</a>

Alternative codes found

RIV/67985831:_____/21:00538188 RIV/00216208:11310/21:10438946

Result on the web

<a href="https://www.sciencedirect.com/science/article/pii/S003101822030643X?casa_token=ZGFI_kZ_xz0AAAAA:CldCOHCPfLd4A1ZqxV-mJ4-xaNS4sLGlMml6LbfTDkI-h2SOOTucIJq5JuToiuA9JkrJv9KAiA" target="_blank" >https://www.sciencedirect.com/science/article/pii/S003101822030643X?casa_token=ZGFI_kZ_xz0AAAAA:CldCOHCPfLd4A1ZqxV-mJ4-xaNS4sLGlMml6LbfTDkI-h2SOOTucIJq5JuToiuA9JkrJv9KAiA</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.palaeo.2020.110195" target="_blank" >10.1016/j.palaeo.2020.110195</a>

Result language

angličtina

Original language name

Elemental and isotopic compositions of trench-slope black shales, Bohemian Massif, with implications for oceanic and atmospheric oxygenation in early Cambrian

Original language description

This study examines a lower Cambrian pyrite-bearing black shale–graywacke succession in the Czech Republic interpreted as infill of a deep-marine, extensional trench-slope basin on top of an accretionary wedge that developed during subduction of an oceanic plate beneath the northern margin of Gondwana. The new U–Pb detrital zircon geochronology of the graywacke constrains the maximum age of deposition to 533 +5/−6 Ma, whereas the Re–Os dating of pyrite yielded a younger age of 7 ± 16 Ma. Distribution of major and trace elements and calculated enrichment factors (EF) indicate that this succession was deposited under changing redox conditions over a short time span and that the basin was presumably controlled by tectonic subsidence and varying supply of terrigenous arc-derived material. This depositional setting is reflected by largely variable EFs and delta98Mo and delta53Cr values. Euxinic conditions detected at the base of the sampled black shale interval are documented by the highest values of EFs of redox-sensitive metals (e.g., Mo, U, V, Ni, Co, As) and also the Corg/P (>;1000) and DOPT (>;0.7) values. Black shales show lower delta56Fe values due to the excess of authigenic pyrite-Fe with a mean delta56Fe value of −0.02per mille over detrital Fe in graywacke with a mean delta56Fe value of +0.25per mille. However, the Fe isotopic signatures of the black shales are not consistent with iron shuttling, mixing of authigenic and detrital sources, or hydrothermal metal enrichment. Instead, they most likely resulted from partial oxidation of pyrite through the syndepositional oxidizing hydrothermal fluids (Si–Ba enrichment), which resulted in precipitation of isotopically heavy Fe-oxyhydroxides. We propose that our maximal recorded delta98Mo value (+ 0.98per mille) might represent the best estimate for the ancient local seawater Mo composition at around 533 Ma and argues against deep-ocean oxygenation in the early Cambrian. On the other hand, the Se/Co ratios of synsedimentary pyrite indicate a mean atmosphere O2 value of ~27percent.

Czech name

—

Czech description

—

Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10505 - Geology

Project

<a href="/en/project/GA20-13644S" target="_blank" >GA20-13644S: Cherts and carbonates as geochemical proxies of paleoenvironmental conditions and Ocean Plate Stratigraphy</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2021

Confidentiality

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

Name of the periodical

Palaeogeography, Palaeoclimatology, Palaeoecology

ISSN

0031-0182

e-ISSN

—

Volume of the periodical

564

Issue of the periodical within the volume

February : 110195

Country of publishing house

NL - THE KINGDOM OF THE NETHERLANDS

Number of pages

21

Pages from-to

nestránkováno

UT code for WoS article

000636756800021

EID of the result in the Scopus database

2-s2.0-85100186796