Ironstone as a proxy of Paleozoic ocean oxygenation

Matheson, Edward J.; Pufahl, Peir K.; Voinot, Alexandre; Murphy, J. Brendan; Fitzgerald, Danielle M.

doi:10.1016/j.epsl.2022.117715

Cited by 16 publications

(3 citation statements)

References 39 publications

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“…Upper Ordovician chamosite oolitic ironstones, largely coeval to our Yangtze example, have been recognized on other peri‐Gondwana blocks (for example, Iberian) as well as on Baltica and Laurentia (Fig. 1A; Young, 1989a; Van Houten & Arthur, 1989; Mücke, 2006; Pufahl et al ., 2020; Matheson et al ., 2022). Aside from being attributed to condensed sedimentation during transgression (Van Houten & Hou, 1990), the oolitic ironstones have also been connected to transgression‐induced upwelling of ferruginous deeper water, which pumps ferrous iron to shallow environments and fuels the chamosite formation (i.e.…”

Section: Discussionmentioning

confidence: 99%

“…Chamosite is a common mineral formed by marine authigenesis (Harder, 1978; Glenn & Filippelli, 2007), which refers to mineral crystallization in the water column or within the top few decimetres of seafloor sediments where seawater prevails ( sensu Matheson et al ., 2022). This authigenic origin of chamosite has been supported by synthetic experiments (Harder, 1978).…”

Section: Discussionmentioning

confidence: 99%

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Microbe‐mediated, marine authigenic formation of ooidal chamosite: Insights from upper Ordovician carbonates of the South‐Western Yangtze platform (China)

et al. 2023

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Chamosite is a common marine authigenic mineral and microbial involvement has been often assumed during its formation. However, the fossil record of such microbial activity is ambiguous. Chamosite oolitic ironstones widely occur in the Upper Ordovician of the Yangtze Platform, but their origin remains unclear. In this study, detailed sedimentological and mineralogical investigations on ironstones from the Haima section (south-western Yangtze Platform) helped unravel the critical role of cyanobacterial activity during marine chamosite authigenesis. Stratigraphically, deposition of the Haima oolitic ironstones corresponded with an early Katian transgression, temporally equivalent to many other early Palaeozoic counterparts worldwide. Petrographic observations revealed that different chamosite forms (ooids, peloids and matrix) all developed in close association with calcified cyanobacteria, suggesting that cyanobacteria-involved chamosite formation existed across a wide range of hydrodynamic conditions from above fairweather wave base to below storm wave base. Further mineralogical characterization (backscatter imaging and electron-microprobe analyses) at singlegrain scale revealed clear mineral zonation from the matrix (dispersed iron oxide and microquartz) through the calcified cyanobacterial sheaths (dispersed chamosite) to the ooid (chamosite). This zonation is best explained by cyanobacterial microbial mats that created benthic reducing and high-pH conditions. These conditions drove near-seafloor, dispersed iron oxide and microquartz (primary precipitates formed in oxic seawater) to form chamosite. The authigenic chamosite, originally dispersed within and surrounding the microbial mats, could be reworked to develop other chamositic grains. It is proposed here that the early Katian transgression was responsible for the chamosite-oolitic-ironstone development. The marine transgression submerged earlier-exposed lands and likely supplied Fe-Al-rich colloidal materials to an open marine setting for the chamosite authigenesis. Moreover, transgression likely triggered upwelling, delivered ferruginous deeper water as an extra Fe source and provided nutrients for the cyanobacterial microbial-mat development, which was essential for the widespread chamosite authigenesis across the south-western Yangtze Platform.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Microbe‐mediated, marine authigenic formation of ooidal chamosite: Insights from upper Ordovician carbonates of the South‐Western Yangtze platform (China)

et al. 2023

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“…Young, 1989), although a recent model proposes significant iron contributions from upwelling of ferruginous waters derived from deep sea hydrothermal vents (e.g. Todd et al ., 2019; Pufahl et al ., 2020; Dunn et al ., 2021; Matheson et al ., 2022). The Cambrian shale and limestone strata of the Avalon Zone comprise: (i) ferruginous oncoids associated with chamosite interbeds, phosphatic hardgrounds, scouring diastems and storm‐derived pebbles; and (ii) synsedimentary Cu–Pb–Zn–Fe and baryte, fissuring and stockwork ore bodies (e.g.…”

Section: Phosphogenesis and Coastal Upwelling Of Ferruginous Seawatermentioning

confidence: 99%

Carbonate production and reef building under ferruginous seawater conditions in the Cambrian rift branches of the Avalon Zone, Newfoundland

Álvaro,

Mills

2024

Sedimentology

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The characterization of carbonate production on rift basins is critical for understanding the nucleation and demise of reefs in tectonically active areas. A new petrographic and mineralogical analysis of Cambrian strata from the Avalon Zone in Newfoundland, based on scanning electron microscopy – back‐scattered electron detector and Raman spectrometer analyses, facilitates recognition of several episodes of Terreneuvian–Miaolingian carbonate production and associated precipitation of ironstone and phosphorite. These distinct units mainly developed on uplifted rift shoulders and basaltic lava palaeoreliefs, and reflect amalgamated high‐energy events, interrupted by scouring discontinuities (diastems) commonly lined by phosphatized and ferruginized microbial crusts. Mud‐mounds, in contrast, nucleated under calm conditions episodically punctuated by high‐energy episodes, where scattered thromboid structures occur as both clotted textures and distinct calcimicrobes. Precipitation of hematite/goethite versus chamosite couplets, both occluding primary porosities and replacing interlaminae and cortices of oncoids and coated aggregates, point to marine substrates close to the Fe‐redox boundary. Upwelling of phosphate‐rich ferruginous hydrothermal waters contributed to the precipitation of ironstone and phosphate interbeds. Ferruginous waters related to penecontemporaneous hydrothermal activity, reflected by the record of synsedimentary fissuring and stockwork ore bodies, were delivered to confined rift‐related horst‐and‐graben settings, largely controlled by the development of specific Cambrian carbonate and associated ironstone facies. The influence of ferruginous waters necessarily affected the record of climatically sensitive evaporitic pseudomorphs, reefs/mounds and phosphorites, which are then not suitable criteria to discriminate palaeolatitude, as demonstrated by a comparison of low‐latitude to middle‐latitude margins fringing Baltica, and the Avalonian and Atlas – Ossa‐Morena – Northarmorican rift transects of West Gondwana.

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Surface water oxygenation and low bioproductivity during deposition of iron formation of the Jacadigo Group (Brazil): Insights from combined cadmium – Chromium isotopes

Frei,

Gaucher,

Boggiani

et al. 2024

Chemical Geology

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Ironstone as a proxy of Paleozoic ocean oxygenation

Cited by 16 publications

References 39 publications

Microbe‐mediated, marine authigenic formation of ooidal chamosite: Insights from upper Ordovician carbonates of the South‐Western Yangtze platform (China)

Microbe‐mediated, marine authigenic formation of ooidal chamosite: Insights from upper Ordovician carbonates of the South‐Western Yangtze platform (China)

Carbonate production and reef building under ferruginous seawater conditions in the Cambrian rift branches of the Avalon Zone, Newfoundland

Surface water oxygenation and low bioproductivity during deposition of iron formation of the Jacadigo Group (Brazil): Insights from combined cadmium – Chromium isotopes

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