Mineralogy and geochemistry of pattern formation in zebra rock from the East Kimberley, Australia

Coward, Andrew J.; Slim, Anja C.; Brugger, Joël; Wilson, Siobhan A.; Williams, Tim; Pillans, Brad; Maksimenko, Anton

doi:10.1016/j.chemgeo.2023.121336

Cited by 2 publications

(3 citation statements)

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Section: Introductionmentioning

confidence: 99%

“…As one of the most remarkable examples of self-organized structures in nonliving systems, the zebra rock from Kimberley, Australia, is characterized by brilliant patterns of red-brown bands consisting of iron oxide against a white background (Figure ). Although the formation mechanism of self-organized patterns in rocks such as zebra rock remains a matter of debate, several reports have discussed this phenomenon in terms of the Liesegang mechanism, – which can explain the spontaneous formation of periodic structures with a characteristic regularity . Various researchers have focused on the relationship between chemically observable Liesegang pattern formation and geologically observable pattern formation using both experimental and numerical simulation approaches.…”

Section: Introductionmentioning

confidence: 99%

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Chemical Model for Pattern Formation in Rocks via Periodic Precipitation of Iron Oxide Minerals

Yatsuda,

Tsushima,

Fang

et al. 2023

ACS Earth Space Chem.

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The zebra-like striped patterns that spontaneously appear in rocks are characterized by periodic self-organized red-brown bands consisting of iron oxide minerals. Although the formation of periodic iron oxide precipitates has been discussed in terms of the Liesegang mechanism, the details remain unclear. Herein, we used chemical experiments and numerical simulations to reproduce the periodic precipitation of iron oxide minerals in a gel medium. The diffusion flux of NaOH into the gel medium containing ferrous ions resulted in the periodic precipitation of Fe(OH)2. Based on the periodicity and dependence on the electrolyte concentration, these Fe(OH)2 precipitates formed via a Liesegang-type mechanism, as indicated by the spacing law and Matalon–Packter law. Further aerobic oxidation converted the Fe(OH)2 pattern into an FeOOH pattern without changing the periodic bands. Although our experimental conditions did not allow geothermal conditions to be reproduced, further oxidation at high temperatures is expected to yield an Fe2O3 pattern. Thus, it was concluded that the Liesegang-like Fe2O3 patterns form via initial salt formation and precipitation of Fe(OH)2, which is subsequently oxidized into FeOOH and Fe2O3. The Fe(OH)2 pattern formation process was also obtained numerically using a reaction–diffusion simulation that considered a continuous flux of the ferrous ions into the reaction field. These experiments and simulations offer an improved understanding of the formation of rocks with periodic self-organized patterns of iron oxide minerals via the Liesegang mechanism.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Chemical Model for Pattern Formation in Rocks via Periodic Precipitation of Iron Oxide Minerals

Yatsuda,

Tsushima,

Fang

et al. 2023

ACS Earth Space Chem.

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“…Reaction–diffusion systems combine diffusion (as a mass transport) and chemical reaction networks, resulting in self-organized static spatial or spatiotemporal patterns. − Such pattern formation has been commonly observed in animate , and inanimate − systems. One of the well-known classes of chemical self-organization in reaction–diffusion systems is the periodic precipitation or Liesegang phenomenon, which creates a periodic precipitation pattern known as the Liesegang pattern (LP). , Depending on the geometry of the reaction front, three different pattern structures can be obtained: bands, , concentric rings, , and onion-like layered shells in 3D .…”

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confidence: 99%

Periodic Precipitation in a Confined Liquid Layer

Itatani,

Onishi,

Suematsu

et al. 2024

J. Phys. Chem. Lett.

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Pattern formation is a ubiquitous phenomenon in animate and inanimate systems generated by mass transport and reaction of chemical species. The Liesegang phenomenon is a self-organized periodic precipitation pattern always studied in porous media such as hydrogels and aerogels for over a century. The primary consideration of applying the porous media is to prevent the disintegration of the precipitation structures due to the sedimentation of the precipitate and induced fluid flow. Here, we show that the periodic precipitation patterns can be engineered using a Hele−Shaw cell in a confined liquid phase, restricting hydrodynamic instability. The patterns generated in several precipitation reaction systems exhibit spatiotemporal properties consistent with patterns obtained in solid hydrogels. Furthermore, analysis considering the Rayleigh−Darcy number emphasizes the crucial role of fluidity in generating periodic precipitation structures in a thin liquid film. This exploration promises breakthroughs at the intersection of fundamental understanding and practical applications.

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Mineralogy and geochemistry of pattern formation in zebra rock from the East Kimberley, Australia

Cited by 2 publications

References 73 publications

Chemical Model for Pattern Formation in Rocks via Periodic Precipitation of Iron Oxide Minerals

Chemical Model for Pattern Formation in Rocks via Periodic Precipitation of Iron Oxide Minerals

Periodic Precipitation in a Confined Liquid Layer

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