Large Zn isotope variations in the Ni-Mo polymetallic sulfide layer in the lower Cambrian, South China

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00025798%3A_____%2F20%3A00000012" target="_blank" >RIV/00025798:_____/20:00000012 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/abs/pii/S1342937X2030157X?via%3Dihub" target="_blank" >https://www.sciencedirect.com/science/article/abs/pii/S1342937X2030157X?via%3Dihub</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.gr.2020.04.009" target="_blank" >10.1016/j.gr.2020.04.009</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Large Zn isotope variations in the Ni-Mo polymetallic sulfide layer in the lower Cambrian, South China

Popis výsledku v původním jazyce

In South China, black organic-rich shales in the lower Cambrian Niutitang Formation host a Ni-Mo polymetallic sulfide layer that discontinuously extends over ~1600 km. Seawater and hydrothermal origins are among the many suggested hypotheses and are still under debate. In order to discriminate Zn sources, we report Zn isotopes in Ni-Mo polymetallic sulfide layers and their host shales from the Nayong and Zunyi locations in Guizhou province and the Zhangjiajie section in Hunan province. In each section, host organic-rich shales show homogeneous Zn isotope compositions which likely resulted from quantitative scavenging of dissolved Zn from seawater under euxinic conditions. The difference in the average delta66Zn values of organic-rich shales between the two sections in Guizhou (0.76 ± 0.09per mille) and one section in Hunan (0.59 ± 0.10per mille)might reflect variations of Zn isotope gradient with the depth of seawater. Therefore, the organic-rich sediments need not always represent an isotopically light Zn sink, which is dependent on Zn isotope fractionation in the local basin. However, the delta66Zn values in the Ni-Mo polymetallic sulfide layers are different from those of their host shales, indicating that these sulfide layers did not inherit the Zn isotope signal of seawater. Based on the regular increasing trend in delta66Zn values from Nayong (0.54 ± 0.06per mille) to Zhangjiajie (1.34 ± 0.09per mille) and the presence of Pb-Zn mineralization in the Dengying/Doushantuo Formations, we argue that hydrothermal fluids associated with Pb-Zn mineralization could be a major source of Zn in Ni-Mo sulfide layers, especially in the Nayong location. A possible model is that the hydrothermal fluids related to MVT-type mineralization got overprinted on a multiple-sourced synsedimentary sulfide-rich layer. We provide additional evidence that Zn isotopes have great potential as a tracer of metal source and can be applied to similar types of mineralization as e.g., the late Devonian Ni-Zn-PGE Nick deposit (Selwyn Basin, Canada) or elsewhere.

Název v anglickém jazyce

Large Zn isotope variations in the Ni-Mo polymetallic sulfide layer in the lower Cambrian, South China

Popis výsledku anglicky

In South China, black organic-rich shales in the lower Cambrian Niutitang Formation host a Ni-Mo polymetallic sulfide layer that discontinuously extends over ~1600 km. Seawater and hydrothermal origins are among the many suggested hypotheses and are still under debate. In order to discriminate Zn sources, we report Zn isotopes in Ni-Mo polymetallic sulfide layers and their host shales from the Nayong and Zunyi locations in Guizhou province and the Zhangjiajie section in Hunan province. In each section, host organic-rich shales show homogeneous Zn isotope compositions which likely resulted from quantitative scavenging of dissolved Zn from seawater under euxinic conditions. The difference in the average delta66Zn values of organic-rich shales between the two sections in Guizhou (0.76 ± 0.09per mille) and one section in Hunan (0.59 ± 0.10per mille)might reflect variations of Zn isotope gradient with the depth of seawater. Therefore, the organic-rich sediments need not always represent an isotopically light Zn sink, which is dependent on Zn isotope fractionation in the local basin. However, the delta66Zn values in the Ni-Mo polymetallic sulfide layers are different from those of their host shales, indicating that these sulfide layers did not inherit the Zn isotope signal of seawater. Based on the regular increasing trend in delta66Zn values from Nayong (0.54 ± 0.06per mille) to Zhangjiajie (1.34 ± 0.09per mille) and the presence of Pb-Zn mineralization in the Dengying/Doushantuo Formations, we argue that hydrothermal fluids associated with Pb-Zn mineralization could be a major source of Zn in Ni-Mo sulfide layers, especially in the Nayong location. A possible model is that the hydrothermal fluids related to MVT-type mineralization got overprinted on a multiple-sourced synsedimentary sulfide-rich layer. We provide additional evidence that Zn isotopes have great potential as a tracer of metal source and can be applied to similar types of mineralization as e.g., the late Devonian Ni-Zn-PGE Nick deposit (Selwyn Basin, Canada) or elsewhere.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10505 - Geology

Projekt

<a href="/cs/project/GA17-15700S" target="_blank" >GA17-15700S: Formace černých břidlic jako geochemický indikátor paleoenvironmentálních změn a tektonických podmínek podél aktivních kontinentálních okrajů</a><br>

Návaznosti

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

Rok uplatnění

2020

Kód důvěrnosti údajů

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

Název periodika

Gondwana research

ISSN

1342-937X

e-ISSN

—

Svazek periodika

85

Číslo periodika v rámci svazku

September

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

13

Strana od-do

224-236

Kód UT WoS článku

000546704800012

EID výsledku v databázi Scopus

2-s2.0-85086726243