Iron Formation Research Articles

Production of Neoproterozoic banded iron formations in a partially ice-covered ocean

Production of Neoproterozoic banded iron formations in a partially ice-covered ocean

A proposed chronostratigraphic Archean–Proterozoic boundary: Insights from the Australian stratigraphic record

The Mount Bruce Supergroup (MBS) in Western Australia has been central to debates surrounding Precambrian stratigraphic subdivision and is one of the few relatively conformable successions that records both the chronometric Archean-Proterozoic boundary (APB) and the Great Oxidation Event/Episode (GOE) which has previously been proposed as the most practical basis for a chronostratigraphic boundary. Current understanding of the lithostratigraphy, chemostratigraphy, and geochronology of the MBS supports the placement of a chronostratigraphic APB in the vicinity of the contact between the Hamersley and Turee Creek Groups, although a precise boundary awaits the generation and integration of more detailed chemostratigraphic records of the GOE with the physical record. The chronometric APB as presently defined at 2500 Ma will suffice until consensus is reached regarding a revised definition based on the GOE, and reconciliation of the physical and proxy records of this event. However, the Australian stratigraphic record suggests placement of the APB either at the base of the first glacial diamictite, or at the top of the last banded iron formation (BIF) below the GOE. The first option would exclude some BIF from the Siderian, which in both cases would be the terminal period of the Archean, whereas the second option places all diamictite in a new period at the start of the Paleoproterozoic. It is further proposed that this new period be named to primarily reflect this glacial influence, rather than for the influence of the GOE which relies on less obvious laboratory-based proxies for its identification.

Paleoproterozoic Rocks of the Belcher Islands, Nunavut: A Review of Their Remarkable Geology and Relevance to Inuit-led Conservation Efforts

The Paleoproterozoic Belcher Group (ca. 2.0 to 1.83 Ga) occurs on the remote Belcher Islands of Hudson Bay in Nunavut, Canada. It includes nearly nine kilometres of well-preserved siliciclastic and carbonate sedimentary rocks, deposited initially in a marginal to shallow marine setting representing one of the first true continental shelf environments on the proto-Canadian Shield. A wide variety of depositional facies exists within the Belcher Group, and it is particularly well known for its spectacular stromatolites in dolostone. In addition to these macroscopic features, two of its formations (Kasegalik and McLeary) contain intact microfossils of Eoentophysalis belcherensis, the oldest known occurrence of cyanobacteria in the geological record. The uppermost part of the Belcher Group contains sedimentary rocks of very different character that represent a younger foreland basin that developed in response to accretionary and collisional processes of the Trans-Hudson orogen. These younger formations (Omarolluk and Loaf) consist of a thick sequence of turbidites, overlain by arkose and other immature clastic sedimentary rocks. A defining characteristic of the Omarolluk Formation is the presence of calcareous concretions. The Omarolluk Formation shares attributes with “omars”, which are glacially transported clasts that occur both locally and further afield throughout parts of Canada and the northern United States and have helped characterize Pleistocene ice-flow trends across the continent.  The Belcher Group also includes two formations dominated by spectacular mafic volcanic rocks. The earlier episode, represented by the Eskimo Formation, reflects eruption of largely subaerial volcanic flows interpreted to represent flood basalt associated with the rifting of Archean basement during the establishment of the continental shelf. A later volcanic episode (the Flaherty Formation) is dominated by submarine pillowed basalt flows and has been assigned to varied tectonic settings, including volcanic arcs related to subduction and oceanic plateaus related to mantle plume activity and renewed rifting along the continental margin. This later volcanism marks the transition from shelf to foreland basin. Mafic sills and related intrusions (Haig intrusions) occur in the middle and lower part of the Belcher Group. Thermal and chemical interactions between mafic magma and calcareous shale generated unusual rocks that are well known in Nunavut as high-quality artisanal carving stone. The Belcher Group also contains Superior-type iron formations that have attracted past exploration interest.   The Belcher Group is a unique geological entity defined by its wide variety of rock types, its superb exposures, and its potential to illustrate many important geological processes in a formative time in Earth’s history. It is also a unique microfossil paleontological resource, and its deposition brackets a crucial and much-debated interval of Precambrian atmospheric and oceanic evolution. It represents an important scientific resource in the context of understanding such changes. This general review paper highlights its most important features, discusses its potential for future research and contributes to wider discussions about its possible future role as a protected area within Nunavut.

The Petrography and geochemistry of iron-bearing units from Mingo’o area (Ntem complex, southern Cameroon)

The banded iron formation (BIF) of the Mingo’o region is located on the northern edge of the Congo Craton. They constitute a significant component of the southern Cameroonian Archean to Paleoproterozoic. Petrographic description indicates that the most characteristic facies of the Mingo'o BIFs are quartz-magnetite BIFs (QMB), which are mostly composed of magnetite and quartz. Geochemistry analyses show that the major elements of this BIF are very simple, with SiO2 and Fe2O3 representing 95.25 wt. % of the bulk rock on average. The low concentrations of Al2O3, TiO2, and HFSE reveal that these chemical sediments are detritus-free. According to Paerson's major element correlation matrix, there is a slight contribution of detrital material to chemical sediment, as confirmed by the strong positive correlation (r = 0.72) of Al and Ti, also by the binary diagrams Al vs. Σ(Y + Nb + Zr) with a weak positive correlation (r2 = 0.31) and Al vs. ΣREE with a zero correlation (r2 = 0.08), indicating that the detrital input was insignificant. The transition metals Zn, Cr, Sr, and V are among the trace elements with low enrichments. This suggests the direction of the volcanogenic hydrothermal input in chemical precipitates. The mean ∑REE concentration of the studied BIF is 26.74 ppm, with a range of 8.82 to 36.74 ppm. Pure chemical sediments are comparable to that. The shale-normalized patterns display minor positive europium anomalies, a sharp decrease in heavy REE, and enrichment in light REE. These geochemical characteristics suggest that the hydrothermal activity in the deep ocean, coupled with seawater, was the source of the Fe and Si. Low-temperature hydrothermal solutions play a key role in the studied BIF, as shown by the absence of a notable positive Eu anomaly. Ce anomalies are seen in the chrondrite-normalized REE patterns, which are characterized by LREE-enriched (mean LaCN/YbCN = 5.28) and HREE depletion (mean TbCN/YbCN = 1.04) patterns. This may indicate that the BIF within the Mingo’o region was formed in place of the basin towards redoxcline, alternating at different times and under various influences from the influx of seawater that has been oxidized.

Ash Fluidity and Regulation Mechanism of Iron-Rich Low-Rank Coal in High-Temperature Gasification Process

ABSTRACT To realize the high-efficiency utilization of iron-rich coal, it is necessary to conduct research on ash flow characteristics and regulatory mechanisms. The ash flow test was carried out, and we introduced additives such as Huajin red mud (HJ), pipe scale (GDG), diatomite (GZT), and Naomaohu coal (NMH). The results revealed that the elevated Fe2O3 content triggers the formation of metallic iron, leading to poor high-temperature fluidity. NMH and HJ additives have the ability to depolymerize SiO2 and Al2O3 structures. This generates higher contents of anorthite and sodium nepheline. The inclusion of GDG ash promoted the formation of cordierite and forsterite, contributing to improved slag flow. Caution is warranted when using a higher proportion of GDG ash additive, as excessive MgO can combine with Al2O3 to form a high-melting-point spinel mineral. GZT ash leads to an increase in quartz content. During cooling, mullite preferentially precipitates from the liquid phase, further reducing high-temperature fluidity.

The felsic volcanism associated BIF-like iron formations: Their origin and implication for BIFs

The Banded Iron Formations (BIFs) have been invaluable archives for the Precambrian eons, providing evidence for the paleoenvironment conditions, including the atmospheric oxygen levels. This study explores the geological origin and depositional mechanism of BIF-like Carboniferous Heiyingshan (HYS) and Mesoproterozoic Pilot Knob hematite (PKH) formations, characterized by hematite-rich (Fe-rich) layer and quartz-rich (Si-rich) jasper layer alternations within felsic volcanic rocks. Through comprehensive mineralogical analyses and geochemical modeling, we present evidence supporting their formation in intra-caldera hot spring lakes, where episodic inputs of Fe(H3SiO4)2-bearing fluids mixed with ambient lake water. Experimental simulations and PHREEQC modeling corroborate a mechanism where ferrihydrite and amorphous silica precursors sequentially precipitate, possibly driven by the oxidation and decomposition rates of Fe(H3SiO4)2 complexes. The sharp or gradational change in the Fe- and Si-rich layering transition can be caused by varying atmospheric oxygen levels. The Carboniferous HYS specimen exhibits a sharp FeSi boundary that is in accordance with modeling under high atmospheric O2 condition. In contrast, the Mesoproterozoic PKH sample contains both sharp and gradual change in the FeSi transition, implying the pO2 lies between 10−3 and 10−5. This chemical precipitation model of BIF-like iron formations could provide insights into the FeSi source and banding mechanism of BIFs, and Precambrian pO2 levels.

Shear zone-hosted hypogene high-grade iron deposit: The Cuité case study

The Cuité iron ore deposit consists of high-grade schistose lenses (>60 wt% Fe) hosted in a tectonic sliver of iron formation associated to mica schist (Serra da Serpentina Group). It is located at the southeastern border of the São Francisco Craton, enclosed by sheared Sthaterian granitoids (Borrachudos Suite), Neoarchean ortogneiss (Guanhães Complex), quartz and pegmatite veins. The iron formation encloses schistose to massive high-grade ore lenses, with a pervasively, continuous to anastomosed schistosity defined by millimetric elongated hematite plates and quartz grains enclosing hematite granoblastic domains. Kenomagnetite/maghemite and martite pseudomorphs (after magnetite) overgrow the foliation and intergrow with granoblastic hematite. Three high-grade iron ore types are identified, according to the fabric and mineralogy of the main iron oxides: lamellar-granular hematitic (LGO), magnetitic (MO), and granular hematitic ore (GO). Intrusive pegmatite bodies related to the swarms of the Eastern Brazilian Province (late Ediacaran to early Cambrian) and to post-collisional Cambrian vents of the Brasiliano Orogeny caused extensive hydrothermal alteration in the country rocks, encompassing recrystallization of the detrital zircon grains from the associated psammopelitic units, which yielded Cambrian ages, formation of kaolinite-rich lenses, and generation of granoblastic ore bodies. The association of intense stretching along foliation and circulation of hydrothermal fluids from pegmatite intrusion is responsible for the ore formation.

Geochemistry and U-Pb zircon geochronology of the Nkout banded iron formations and associated metasiliciclastic rocks, NW Congo craton, southern Cameroon

ABSTRACT The Nkout banded iron formations (BIFs)-hosted iron deposit is located in the Ntem Complex at the northwestern part of the Congo craton, southern Cameroon. We report geochronological and geochemical data of magnetite BIFs and interlayered mica schists from the Nkout iron ore deposit. The BIFs show typical features of chemical precipitates characterized by seawater-like shale-normalized rare earth elements plus yttrium spectra. Weak positive Eu anomalies indicate the contribution of high-temperature hydrothermal fluids to the BIFs, with low detrital input. The absence of true Ce anomalies indicates that the BIFs were likely to be deposited in anoxic seawater. LA-ICP-MS U-Pb detrital zircon data for the BIFs and associated metasiliciclasltic rocks constrained the maximum depositional age at ca. 2.8 Ga, suggesting that the Nkout BIFs are likely the oldest iron formations in the Ntem Complex. Our zircon U-Pb isotope data indicate that the Nkout succession experienced lower-amphibolite facies metamorphism at ca. 2.0 Ga, which correlates with the regional tectono-thermal event linked to the convergence and assembly of terranes between the Congo and São Francisco cratons during the Eburnean-Transamazonian orogeny.

Vestiges of Earth’s earliest depleted mantle reservoir

There is a paucity of evidence preserved in the rock record regarding Earth’s earliest enriched crust and its complementary depleted mantle during the Hadean. In recent years, vestiges of these early reservoirs have been inferred by examination of Hf isotope systematics compiled from zircons. The Singhbhum craton of Eastern India, for example, preserves only the existence of an enriched (εHf <0) crustal reservoir during the Hadean−Eoarchean, with the notable absence of a depleted mantle reservoir signature (εHf >0) until ca. 3.5 Ga. Here we report a new Sm-Nd isochron for the Lower Lava greenstones of the western Iron Ore Group from the Singhbhum craton, confirming a 3.42 ± 0.14 Ga crystallization age with an initial εNd of +5.7 ± 2.5. This is the highest positive εNd value derived from an isochron of this age. We infer that this depleted mantle source is a vestige complementary to the primary crust following planetary differentiation. Furthermore, we present U-Pb zircon ages for a 3.39 ± 0.02 Ga tuff that lies stratigraphically above the Lower Lava and <30 cm below an extensive conformable banded iron formation (BIF). This age implies that the western Iron Ore Group’s BIF is the largest economic-grade iron formation of its Paleoarchean age, suggesting that free atmospheric oxygen existed as more than just whiffs at this time.

The role of polyphase deformation in the formation of iron deposits and gold mineralization in the paleoproterozoic nyong complex greenstone belt (Southwestern Cameroon)

The Toko-Nlonkeng area is situated in the Nyong Complex of the northwestern Congo craton. In this study, airborne geophysical data (radiometric and magnetic) and structural data (outcrops and core samples) were used to investigate the relationship between structural evolution, iron formation (IFs)-hosted iron ore deposits, and gold mineralization in the Paleoproterozoic Nyong complex greenstone belt in southwestern Cameroon. Magnetic and radiometric trends, combined with field data, show general NE-SW, NW-SE, and E-W directions that correlate with the main gold-bearing structures. The study area has undergone four (04) deformation phases relating to polycyclic metamorphic and magmatic events. The D1 and D2 phases are the result of progressive ductile and transpressional deformation; D3 is a brittle-ductile deformation; and D4 is essentially brittle with various types of fracture networks late to post-orogenic. The D3 deformation phase is characterized by constrictive deformation with C3 shears and meso‑ to mega-P3-folds, and the main stress axes show φσ2 > φσ1> φσ3, reflecting a shearing tectonic regime with a maximum E-W shortening. This polyphase deformation is derived from the Eburnean/Trans-Amazonian deformation related to the collision between the Congo and São Francisco cratons. The main strain in the structural style of the Nyong Complex appears to be transpressive tectonics. This study reveals that iron ore and gold mineralization were mostly found on the hinges of folds and confirms that folding shear zones controlled the iron ore and gold target in the Nyong Complex and Northeast Brazil. The study proposes an approach to optimize future exploration activity based on the integration of the data.

Integration of airborne magnetic and geological data for mineral prospectivity mapping in the Ambam-Amvom rainforest area, Archean Ntem Complex, southern Cameroon

The accurate mapping of mineral resources in rainforest areas is challenging due to dense vegetation and thick lateritic cover obscuring rock outcrops. This study utilized airborne magnetic survey data to map geological features and target mineral resources in the Ambam-Amvom area at the NW margin of the Congo craton. Linear and non-linear filtering algorithms were used, including reduction to the equator (RTE), upward continuation (UC) at 1000 m and 2000 m, first vertical derivative (FVD), and analytic signal (AS). Field surveys were carried out for sampling and petrographic investigations. The TMI map showed magnetic signals varying from -4489 nT to 2317 nT, while the RTE map displayed magnetic signals varying from -2984 nT to 3528 nT. The RTE-Reg map exhibited anomaly signal variations ranging between -2704 nT and +3637 nT and between -2829 and +3864 nT, respectively for UC at 1000 m and 2000 m. Geological structures were interpreted from the FVD, AS, and TMI-RTE images, and linear structures of regional extend mainly trend NW-SE, E-W, and NE-SW. Field investigations revealed that the study area comprises iron formations, amphibolite, gneiss, gabbro, biotite granite, and charnockite. The bulk chemical composition of iron formations showed a high content of TFe, averaging 39.80 wt.% for itabirite, 53.79 wt.% for hematite-geothite ore and 59.63 wt.% for quartz-hematite ore. The zones of peak magnetic anomalies coincided with the occurrence of the greenstone belt, and the integration of aeromagnetic and geological data led to the identification of three main target zones for iron ore minimization. High fracture density zones within the research were identified as high prospective targets for gold mineralization. The study's findings highlight the high potential of the Ntem Complex for mineral resources and provide valuable information for future research and development.

Understanding the crustal architecture beneath the Bangui magnetic anomaly and its interactions with central African tectonic megastructures based gravity and magnetic analysis

The Bangui magnetic anomaly (BMA) in Central Africa is one of the largest continental magnetic anomalies on Earth in terms of amplitude and lateral size. Determining the sources of the BMA can lead to an increased understanding of the crustal dynamic in the Central African sub-region and the African continent as a whole. Magnetic and gravity analysis-based derivative, two-dimensional forward modelling and a Curie isothermal depth, showed that (a) the bottoms of the magnetic sources were between 15 and 35 km; (b) the BMA is a coalescence of several anomalies that trend E-W and roughly NE-SW. These directions coincide with regional Pan African-aged shear zones along the Central African orogenic belt and to thrust sheets at the northern edge of the Congo Craton. The depth of magnetization does not exceed 35 km with the amplitude of magnetization becoming smaller in the Central African Republic. The potential magnetic susceptibility sources have an average density of 2850 kg/m3 and magnetic susceptibilities between 0.06 and 0.25 SI. The BMA is interpreted to be a combination of middle and lower crustal bodies that are not continuous and consist of magnetic mineral rich granulites and banded iron formations. The gravity and magnetic modelling indicate that the entire crust was involved in the Pan African collisional event similar to what is seen in the Mozambique belt in East Africa. Combined with geological and geochemical studies, the models add evidence that one or two subduction zones were involved in accreting terranes on the northern edge of the Congo Craton. The tectonic accretions caused a crustal remobilization along major shear zones that has locally contributed to a probable circulation of fluids enriched in ferromagnesian minerals during late Neoproterozoic magmatism that created the BMA sources.

Geochemistry and Formation Conditions of Mesoarchean Banded Iron Formations (BIF-1) from the Kostomuksha Greenstone Belt, Karelian Craton

Geochemistry and Formation Conditions of Mesoarchean Banded Iron Formations (BIF-1) from the Kostomuksha Greenstone Belt, Karelian Craton

On the formation of dendritic iron from alkaline electrochemical reduction of iron oxide prepared for metal fuel applications

Low-temperature electrochemical reduction (electroreduction) of iron oxides is a promising alternative to the conventional methods for iron production due to its CO2-free operation and relatively low energy consumption. In this work, we demonstrate a novel approach for electrochemical iron production by promoting the formation of dendritic structures during iron electrodeposition, which facilitates the easy harvesting of deposits in powder form. Experiments were conducted using a single pair of parallel plate electrodes, immersed in a mixture of hematite (Fe2O3) powder and aqueous alkaline (NaOH) slurry. The effects of current density, Fe2O3 mass fraction, temperature, and powder size on current efficiency and deposit morphology are investigated. A large quantity of dendritic iron structures is observed when experiments are carried out without stirring and/or applying heat from a heating plate. This condition suggests temperature and (ion/species) concentration gradients in the system. The dendrites are mainly deposited on the cathode's sides, corners, and edges. Different deposits and dendritic structures (compact layer deposit, moss-like deposit, deposit with whisker-like dendrites, and deposit with crystal-like dendrites) are observed as operating conditions change. Overall, a cathodic deposition of metallic iron with a high Faradaic efficiency (≥90 %) is successfully accomplished. The present findings provide new insights into the production of electrolytic iron powder and its future use as a carbon neutral and sustainable fuel/energy carrier.

Geology, geochemistry, mineralization and fluid inclusion characteristics of the SW of Hormuz Island banded iron formations, southern Iran

The Hormuz Island banded iron formations (HIBIFs) are situated at the Zagros Folded Zone in southern Iran. The BIFs occur intercalated with the Neoproterozoic Hormuz series, an evaporite and siliciclastic succession with pyroclastic rocks, and were deposited on the continental rift margin of the Arabian plate. The HIBIFs are banded rocks consisting of the alternation of dark Fe-rich and reddish-brown Si-rich layers, and belong to oxide facies iron formations. The post-Archean Australian shale normalized rare earth elements and yttrium patterns of HIBIFs have the characteristics of both hydrothermal solutions and seawater. The sharp positive Eu anomaly (2.10–6.90) may be inherited from high-temperature hydrothermal solutions, while slightly negative Ce anomalies (0.57–0.82) are inherited from seawater. The homogenization temperature and salinity of primary fluid inclusions range from 180.7 to 474.3°C and from 2.24 to 12.85 wt% NaCl, respectively, which suggests that intermediate- to high-temperature hydrothermal fluids and seawater contributed to the formation of the HIBIFs. The Eu/Sm and Sm/Yb ratios in BIFs are between the values of hydrothermal fluids and seawater. In summary, all geological and geochemical data suggest that the HIBIFs are a post-great oxidation event iron formation pulse at the end of the Ediacaran period. However, this is actually not similar to Neoproterozoic syn-glacial iron formations. Instead, this is a new occurrence of iron formation in an overlooked/understudied time period when either global or local conditions were conducive to iron deposition. The iron deposition on Hormuz Island does not appear to be triggered by fluctuating atmospheric oxygen or sea-level variations, but instead may be related to syn-basinal volcanism in the active continental rift margin environment in anoxic submarine condition. Thematic collection: This article is part of the Geochemical processes related to mined, milled, or natural metal deposits collection available at: https://www.lyellcollection.org/topic/collections/geochemical-processes-related-to-mined-milled-or-natural-metal-deposits

LATE ARCHEAN SHELF-TO-BASIN IRON SHUTTLE CONTRIBUTES TO THE FORMATION OF THE WORLD-CLASS DATAIGOU BANDED IRON FORMATION

Abstract Banded iron formations (BIFs) are among the few chemical sedimentary archives that capture the biogeochemical evolution of Fe cycling and the redox evolution of the early Earth. Although biologically recycled continental Fe has been previously proposed to be a significant source of Fe in BIFs deposited from a stratified ocean at the onset of the Great Oxidation Event (GOE; ~2.5–2.2 Ga), constraining Fe sources and pathways in Archean BIFs remains challenging. Here we present major and trace element and Fe-Nd-Cr isotope data for the largest BIF (i.e., Dataigou) in China to test whether a benthic Fe shuttle was operative during deposition of pre-GOE BIFs. The absence of true, shale-normalized Ce anomalies, coupled with unfractionated Cr and positive Fe isotope compositions, suggests that BIF deposition occurred in an anoxic water column under reducing atmospheric conditions, whereas positive Eu anomalies indicate a significant input from a high-temperature hydrothermal source. Based on a significant correlation between initial Nd and Fe isotope data, we suggest that two Fe sources were periodically mixed and resulted in deposition of the Dataigou BIF. Here, we suggest the following sources: (1) hydrothermal fluids from sea-floor systems (low εNd(t) and high δ56Fe), derived from the interaction of fluids with underlying, older continental crust, and (2) a benthic Fe flux (high εNd(t) and low δ56Fe), generated by microbial Fe(III) reduction in coastal sediments during weathering of a nearby depleted landmass. Results presented here confirm, for the first time, that a microbially driven Fe shuttle was operational and supplied Fe on a basin-wide scale in the absence of atmospheric oxygen.

Geochemistry and depositional environment of the Neoproterozoic Ereen and Dartsagt banded iron formation (BIF) deposits in the Idermeg terrane, eastern Mongolia

Geochemistry and depositional environment of the Neoproterozoic Ereen and Dartsagt banded iron formation (BIF) deposits in the Idermeg terrane, eastern Mongolia

Spatiotemporal distribution of invertebrate fauna in a mesovoid shallow substratum in iron formations

Spatiotemporal distribution of invertebrate fauna in a mesovoid shallow substratum in iron formations

Electrochemical properties of magnetite nanoparticles supported on carbon paste electrode in various electrolyte solutions: A study by cyclic voltammetry

Abstract Electrochemical properties of magnetite nanoparticles supported on carbon paste electrodes were investigated by means of cyclic voltammetry. The measurements were performed for bare and coated with citrate magnetite nanoparticles in aqueous solutions of various electrolytes: NaCl, NaClO4, and Na2HPO4. Cyclic voltammetry curves obtained on bare and citrate functionalized Fe3O4 nanoparticles are rather similar indicating that the electrochemical properties of the magnetite nanoparticles are not significantly affected by the citrate coating. Cyclic voltammetry scans reveal the formation of metallic iron below −1.2 V. The defective structure of the oxide phases formed by oxidation of metallic iron seems to play an important role in the chemisorption of chloride ions and their subsequent oxidation. Graphical Abstract

Application of grazing incidence wide-angle X-ray scattering to characterise mechanically plated coatings

Post-mechanical plating heat treatment on zinc and zinc–tin coatings resulted in the formation of an iron–zinc-rich intermetallic layer between the substrate and the coatings, while the outer coating layer became tin-rich in the case of heat-treated zinc–tin coatings. The novel use of grazing incidence wide-angle X-ray scattering detected not only ζ-FeZn13, δ1p-Fe13Zn126 and δ1k-FeZn6.67 phases but also Γ1-Fe11Zn40 and Γ-Fe4Zn9 phases due to the higher resolution and signal-to-noise ratio of synchrotron X-ray diffraction (XRD) compared to traditional XRD. Microstructure evolution models during the heat treatment of mechanically plated zinc and zinc–tin coatings are proposed. The formation of iron–zinc intermetallic phases was in the sequence of ζ-FeZn13, δ1p-FeZn10, δ1k-FeZn7, Γ-Fe3Zn10 and Γ1-Fe5Zn21 phases when the heat treatment duration increased.