Quinone-mediated dissimilatory iron reduction of hematite: Interfacial reactions on exposed {0 0 1} and {1 0 0} facets

2021 ◽  
Vol 583 ◽  
pp. 544-552
Author(s):  
Shiwen Hu ◽  
Yundang Wu ◽  
Zhenqing Shi ◽  
Fangbai Li ◽  
Tongxu Liu
Keyword(s):  
Iron Reduction ◽  
Interfacial Reactions ◽  
Dissimilatory Iron Reduction

Fulvic Acid-Mediated Interfacial Reactions on Exposed Hematite Facets during Dissimilatory Iron Reduction

Langmuir ◽  
2021 ◽  
Author(s):  
Shiwen Hu ◽  
Yundang Wu ◽  
Fangbai Li ◽  
Zhenqing Shi ◽  
Chao Ma ◽  
...  
Keyword(s):  
Fulvic Acid ◽  
Iron Reduction ◽  
Interfacial Reactions ◽  
Dissimilatory Iron Reduction

scholarly journals Iron and Carbon Isotope Constraints on the Formation Pathway of Iron-Rich Carbonates within the Dagushan Iron Formation, North China Craton

Minerals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 94
Author(s):  
Xiaoxue Tong ◽  
Kaarel Mänd ◽  
Yuhao Li ◽  
Lianchang Zhang ◽  
Zidong Peng ◽  
...  
Keyword(s):  
Iron Reduction ◽  
Isotope Composition ◽  
Iron Formation ◽  
Banded Iron Formations ◽  
Organic C ◽  
Formation Pathway ◽  
Wide Range ◽  
Dissimilatory Iron Reduction ◽  
O Isotope ◽  
Iron Formations

Banded iron formations (BIFs) are enigmatic chemical sedimentary rocks that chronicle the geochemical and microbial cycling of iron and carbon in the Precambrian. However, the formation pathways of Fe carbonate, namely siderite, remain disputed. Here, we provide photomicrographs, Fe, C and O isotope of siderite, and organic C isotope of the whole rock from the ~2.52 Ga Dagushan BIF in the Anshan area, China, to discuss the origin of siderite. There are small magnetite grains that occur as inclusions within siderite, suggesting a diagenetic origin of the siderite. Moreover, the siderites have a wide range of iron isotope compositions (δ56FeSd) from −0.180‰ to +0.463‰, and a relatively negative C isotope composition (δ13CSd = −6.20‰ to −1.57‰). These results are compatible with the reduction of an Fe(III)-oxyhydroxide precursor to dissolved Fe(II) through microbial dissimilatory iron reduction (DIR) during early diagenesis. Partial reduction of the precursor and possible mixing with seawater Fe(II) could explain the presence of siderite with negative δ56Fe, while sustained reaction of residual Fe(III)-oxyhydroxide could have produced siderite with positive δ56Fe values. Bicarbonate derived from both DIR and seawater may have provided a C source for siderite formation. Our results suggest that microbial respiration played an important role in the formation of siderite in the late Archean Dagushan BIF.

The Carboniferous Shikebutai Iron Deposit in Western Tianshan, Northwestern China: Petrology, Fe-O-C-Si Isotopes, and Implications for Iron Pathways

2019 ◽  
Vol 114 (6) ◽  
pp. 1207-1222 ◽  
Author(s):  
Xiuqing Yang ◽  
Jingwen Mao ◽  
Zongsheng Jiang ◽  
M. Santosh ◽  
Zuoheng Zhang ◽  
...  
Keyword(s):  
Iron Ore ◽  
Iron Reduction ◽  
Hydrothermal Fluids ◽  
Northwestern China ◽  
Iron Deposit ◽  
Organic Carbon Content ◽  
Isotope Data ◽  
Western Tianshan ◽  
Dissimilatory Iron Reduction ◽  
Si Isotope

Abstract Submarine volcanic-hosted iron deposits are important sources of iron ore in northwestern China. Here we present the petrological characteristics and coupled Fe-O, C, and Si isotope data of iron ores from the Shikebutai submarine volcanic-hosted hematite deposit in the Western Tianshan region. Several stratiform and lenticular hematite-dominated orebodies occur in Carboniferous submarine volcano-sedimentary sequences in this region. The ores are mainly composed of hematite, quartz, and minor siderite with distinct alternating iron-rich and silica-rich bands. The hematite shows δ56Fe and δ18O values in the range of –0.31 to 0.80‰ and 2.2 to 7.0‰, respectively, and the jasper yields δ30Si values of –1.90 to –1.20‰. Iron and Si were both derived from hydrothermal fluids related to submarine magmatism/volcanism. The Fe-bearing minerals in the Shikebutai deposit define distinct formation pathways. Hematite is the primary dehydrated Fe(III) oxyhydroxide, and the Fe isotope data indicate fractionation resulting from the partial oxidation of Fe(II). The O isotope data reflect inheritance from the submarine hydrothermal fluids source. Jasper was produced during coprecipitation of silica adsorbed onto the Fe(III) oxyhydroxides. The siderite-rich iron ore/volcaniclastic rock samples with a high and variable total organic carbon content (0.14–5.57%) show negative δ13C values (–3.0 to –1.1‰) and light δ56Fe values (–1.11 to –0.84‰). Our isotope data, together with the common occurrence of hematite inclusions in siderite, suggest that siderite was mainly produced by microbial dissimilatory iron reduction during diagenesis. The geologic, petrological, and isotopic data suggest that the Carboniferous Shikebutai deposit was precipitated through chemical and biogenic processes.

scholarly journals Biologically recycled continental iron is a major component in banded iron formations

2015 ◽  
Vol 112 (27) ◽  
pp. 8193-8198 ◽  
Author(s):  
Weiqiang Li ◽  
Brian L. Beard ◽  
Clark M. Johnson
Keyword(s):  
Continental Margin ◽  
Iron Reduction ◽  
Banded Iron Formations ◽  
Nd Isotope ◽  
Isotope Data ◽  
Dissimilatory Iron Reduction ◽  
Wide Scale ◽  
First Time ◽  
Iron Formations ◽  
Marine Basin

Banded iron formations (BIFs) record a time of extensive Fe deposition in the Precambrian oceans, but the sources and pathways for metals in BIFs remain controversial. Here, we present Fe- and Nd-isotope data that indicate two sources of Fe for the large BIF units deposited 2.5 billion y ago. High-εNd and -δ56Fe signatures in some BIF samples record a hydrothermal component, but correlated decreases in εNd- and δ56Fe values reflect contributions from a continental component. The continental Fe source is best explained by Fe mobilization on the continental margin by microbial dissimilatory iron reduction (DIR) and confirms for the first time, to our knowledge, a microbially driven Fe shuttle for the largest BIFs on Earth. Detailed sampling at various scales shows that the proportions of hydrothermal and continental Fe sources were invariant over periods of 100–103 y, indicating that there was no seasonal control, although Fe sources varied on longer timescales of 105–106 y, suggesting a control by marine basin circulation. These results show that Fe sources and pathways for BIFs reflect the interplay between abiologic (hydrothermal) and biologic processes, where the latter reflects DIR that operated on a basin-wide scale in the Archean.

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