Pseudomorphic replacement of diopside during interaction with (Ni,Mg)Cl2 aqueous solutions: Implications for the Ni-enrichment mechanism in talc- and serpentine-type phases

Majumdar, Alik S.; H, King; John, Timm; Kusebauch, Christof; Putnis, Andrew

doi:10.1016/j.chemgeo.2014.04.016

Cited by 14 publications

(10 citation statements)

References 44 publications

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“…Talc-carbonate altered serpentinite samples from the SGC are devoid of awaruite, which has generally not been documented from talc-carbonate altered ultramafic rock elsewhere suggesting that f O2,aq and/or a SiO2,aq during carbonation of peridotite and serpentinite are unfavourable for awaruite formation and preservation. Nickel released from breakdown of awaruite and serpentine due to hydrothermal carbonation primarily partitions into talc reaching concentrations similar to that in primary olivine 43 , 44 , while Ni concentrations in magnesite are below the detection limit (~0.03 wt%) (Fig. 2c , Supplementary Table 3 ).…”

Section: Discussionmentioning

confidence: 99%

Peridotite weathering is the missing ingredient of Earth’s continental crust composition

et al. 2018

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The chemical composition of the continental crust cannot be adequately explained by current models for its formation, because it is too rich in Ni and Cr compared to that which can be generated by any of the proposed mechanisms. Estimates of the crust composition are derived from average sediment, while crustal growth is ascribed to amalgamation of differentiated magmatic rocks at continental margins. Here we show that chemical weathering of Ni- and Cr-rich, undifferentiated ultramafic rock equivalent to ~1.3 wt% of today’s continental crust compensates for low Ni and Cr in formation models of the continental crust. Ultramafic rock weathering produces a residual that is enriched in Ni and also silica. In the light of potentially large volumes of ultramafic rock and high atmospheric CO2 concentrations during the Archean, chemical weathering must therefore have played a major role in forming compositionally evolved components of the early Earth’s crust.

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Section: Discussionmentioning

confidence: 99%

Peridotite weathering is the missing ingredient of Earth’s continental crust composition

et al. 2018

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“…13; Bruno et al 2007;Lippmann 1980). The composition of a solid solution is closely related to how the local solution composition at the reaction interface evolves (e.g., Majumdar et al 2014). It is also influenced by the relative solubilities of the end members, with similar end member solubilities defining a larger range of intermediate compositions ( Fig.…”

Section: Complex Compositional Zoning In Solid Solutions: Local Equilmentioning

confidence: 99%

“…The importance of etch pits to fracture generation was recently demonstrated experimentally for the serpentinization of olivine (Malvoisin et al 2012) and the replacement of scolecite (CaAl 2 Si 3 O 10 ⦁3H 2 O) by tobermorite (Ca 4.5 Na 1.3 Si 5.2 AlO 16 (OH) 2 ;Dunkel and Putnis 2014). result of reaction-induced fracturing is the initial acceleration of the replacement rate due to the generation of new reactive surface area(Jamtveit and Austrheim 2010;Majumdar et al 2014;Røyne et al 2008). Several serpentinization experiments have demonstrated the importance of new surface area generation as replacement is arrested after a limited time despite a high initial rate of replacement in the absence of fracture formation(Godard et al 2013;Malvoisin and Brunet 2014) Jamtveit and Hammer (2012).…”

mentioning

confidence: 97%

Textural and compositional complexities resulting from coupled dissolution–reprecipitation reactions in geomaterials

Altree-Williams

Pring

Ngothai

et al. 2015

Earth-Science Reviews

135

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“…During serpentinisation, olivine shows a higher solubility in the aqueous solution than pyroxene, so its reaction rate is faster than that of pyroxene. Meanwhile, the serpentinisation of olivine can provide favourable alteration conditions for pyroxene, in which an ion‐rich (such as Ni) hydrothermal solution was generated (Majumdar et al, ). Conversely, the release of Cr and Al from pyroxene and spinel can accelerate the serpentinisation rate of olivine (Huang, Song, et al, ).…”

Section: Discussionmentioning

confidence: 99%

“…Experimental results have shown that the interaction of olivine and diopside in mantle peridotite could affect serpentinisation (Majumdar, King, John, Kusebauch, & Putnis, 2014). In addition, pyroxene and spinel limit the serpentinisation and magnetite formation after olivine (Huang, Song, et al, 2017).…”

Section: Factors Influencing Serpentinisationmentioning

confidence: 99%

Serpentinisation and magnetite formation in the Angwu ultramafic rocks from the central Bangong–Nujiang suture zone, Tibetan Plateau

Liu

Tao

et al. 2019

Geological Journal

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Serpentinised ultramafic rocks are widely distributed in the Bangong–Nujiang suture zone (BNSZ) and show close relationship with the regional mineralisation. Here, we investigate the serpentinised ultramafic rocks from Angwu in the central segment of the BNSZ, where the primary minerals include olivine, clinopyroxene, chromite, lizardite, magnetite, and chlorite. Based on a comprehensive analysis of the results from petrography, back‐scattered electron images (BSE), and energy dispersive spectrographs (EDS), as well as electron probe microanalysis (EPMA), the alteration process of the ultramafic rocks, including serpentinisation, can be divided into three stages: 1, formation of relatively Fe‐rich serpentine (Mg#, 0.82), with no precipitation of magnetite; 2, formation of relatively Mg‐rich serpentine (Mg#, 0.93), with precipitation of magnetite in serpentine veins; and 3, alteration of serpentine into chlorite. We computed the reactions associated with alteration process for the above stages. In addition, thermodynamic modelling in multicomponent mineral equilibrium phase diagrams indicate that during the serpentinisation process, the desilication of pyroxene in caused the enhancement of SiO2 activity and restricted the transformation from olivine to magnetite. The reaction temperature for the serpentinisation of these rocks was relatively high, and within this temperature interval (100–300°C), lizardite was stable, and precipitation of magnetite was not favoured. We also evaluate the factors influencing magnetite precipitation during serpentinisation of ultramafic rocks including the composition of primitive rocks and the activity of SiO2 and temperature. Our study provides insights on the mechanism of magnetite mineralisation associated with the serpentinisation of ultramafic rocks.

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Pseudomorphic replacement of diopside during interaction with (Ni,Mg)Cl2 aqueous solutions: Implications for the Ni-enrichment mechanism in talc- and serpentine-type phases

Cited by 14 publications

References 44 publications

Peridotite weathering is the missing ingredient of Earth’s continental crust composition

Peridotite weathering is the missing ingredient of Earth’s continental crust composition

Textural and compositional complexities resulting from coupled dissolution–reprecipitation reactions in geomaterials

Serpentinisation and magnetite formation in the Angwu ultramafic rocks from the central Bangong–Nujiang suture zone, Tibetan Plateau

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