Experimental study of the carbonation of partially serpentinized and weathered peridotites

Hövelmann, Jörn; Austrheim, Håkon; Beinlich, Andreas; Munz, I. A.

doi:10.1016/j.gca.2011.08.032

Cited by 66 publications

(46 citation statements)

References 70 publications

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“…While empty pores facilitate fluid flow and mass transfer, pores filled with reaction products participate in the spreading of the fracturation network through reaction-induced cracking. This observation was already noted in other studies [49,50].…”

Section: Porosity An Alternative and Complementary Way For Reaction supporting

confidence: 86%

Intracrystalline Reaction-Induced Cracking in Olivine Evidenced by Hydration and Carbonation Experiments

et al. 2018

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In order to better understand the microtextural changes associated with serpentinization reactions, natural millimeter-sized olivine grains were experimentally reacted with alkaline NaOH and NaHCO 3 solutions at a temperature of 200 • C and for durations of 3 to 12 months. During hydration experiments, dissolution and precipitation were intimately correlated in time and space, with reaction products growing in situ, either as layered veins or as nearly continuous surface cover. In contrast, carbonation experiments showed a strong decoupling between both processes leading to essentially delocalized precipitation of the reaction products away from dissolution sites. Textural analyses of the samples using scanning electron microscopy, Raman spectroscopy, and X-ray synchrotron microtomography provided experimental evidence for a cause-and-effect relationship between in situ precipitation and intracrystalline reaction-induced cracking in olivine. Juvenile cracks typically nucleated at the tip of dissolution notches or on diamond-shaped pores filled with reaction products, and propagated through the olivine crystal lattice during the course of the reaction. The occurrence of new cracks at the tip of diamond-shaped pores, but also of tiny subspherical pores lining up along microcracks, indicated that fracturation and porosity networks were mutually driven, making serpentinization an extremely efficient alteration process over time. Alternatively, our data suggested that some form of porosity also developed in absence of fracturation, thus further highlighting the remarkable efficiency and versatility of serpentinization processes.

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Section: Porosity An Alternative and Complementary Way For Reaction supporting

confidence: 86%

Intracrystalline Reaction-Induced Cracking in Olivine Evidenced by Hydration and Carbonation Experiments

et al. 2018

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“…In these terrestrial samples, Hövelmann et al. (, p. 6775) noted that “the primary olivine has been directly replaced by calcite along the contact with the surrounding serpentine. The calcite forms a continuous rim around the remnant olivine while the interface is saw‐toothed and decorated with pores.” Thus, although fluid conditions are likely to have been quite different between Oman and the nakhlites, this comparison demonstrates that carbonates can form by replacement of the walls of hydrous silicate veins.…”

Section: Discussionmentioning

confidence: 99%

Opal‐A in the Nakhla meteorite: A tracer of ephemeral liquid water in the Amazonian crust of Mars

Lee

MacLaren

Andersson

et al. 2015

Meteorit & Planetary Scien

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Abstract-The nakhlite meteorites are clinopyroxenites that are derived from a~1300 million year old sill or lava flow on Mars. Most members of the group contain veins of iddingsite whose main component is a fine-grained and hydrous Fe-and Mg-rich silicate. Siderite is present in the majority of veins, where it straddles or cross-cuts the Fe-Mg silicate. This carbonate also contains patches of ferric (oxy)hydroxide. Despite 40 years of investigation, the mineralogy and origins of the Fe-Mg silicate is poorly understood, as is the paragenesis of the iddingsite veins. Nanometer-scale analysis of Fe-Mg silicate in the Nakhla meteorite by electron and X-ray imaging and spectroscopy reveals that its principal constituents are nanoparticles of opal-A. This hydrous and amorphous phase precipitated from acidic solutions that had become supersaturated with respect to silica by dissolution of olivine. Each opal-A nanoparticle is enclosed within a ferrihydrite shell that formed by oxidation of iron that had also been liberated from the olivine. Siderite crystallized subsequently and from solutions that were alkaline and reducing, and replaced both the nanoparticles and olivine. The fluids that formed both the opal-A/ferrihydrite and the siderite were sourced from one or more reservoirs in contact with the Martian atmosphere. The last event recorded by the veins was alteration of the carbonate to a ferric (oxy)hydroxide that probably took place on Mars, although a terrestrial origin remains possible. These results support findings from orbiter-and rover-based spectroscopy that opaline silica was a common product of aqueous alteration of the Martian crust.

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“…6a-c) [47][48][49]. Conjointly, precipitation of the first clusters of brucite and chrysotile occur at the olivine surface.…”

Section: Serpentinization Steps and Reaction Mechanismmentioning

confidence: 99%

Mineral replacement rate of olivine by chrysotile and brucite under high alkaline conditions

Lafay

Montes-Hernandez

Janots

et al. 2012

Journal of Crystal Growth

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International audienceOlivine mineral replacement by serpentine is one major alteration reaction of oceanic hydrothermalism. In the present experimental study, olivine grains were replaced by chrysotile and brucite under high alkaline conditions. In our study, olivine replacement implied a spatial and temporal coupling of dissolution and precipitation reactions at the interface between olivine and chrysotile-brucite minerals. Coupled dissolution-precipitation led to the alteration of starting olivine grains (so-called primary or parent mineral) to a porous mineral assemblage of chrysotile and brucite with preservation of the initial olivine morphology. This mineral replacement reaction of olivine (serpentinization) has been characterized using XRD, FESEM and FTIR measurements. Moreover, a simple and novel method is here proposed to quantify the mineral replacement rate (or serpentinization rate) of olivine by using thermogravimetric (TG) and differential TG (DTG) analyses. Serpentinization extent depends on the grain size: it is complete after 30 days of reaction for the smallest olivine grains (<30µm), after 90 days of reaction for the intermediate olivine grains (30 µm-56 µm) and reaches 55% of olivine replacement after 90 days for the largest fraction (56-150 µm). Based on the fitting of the serpentinization extent (t) versus time (t) by using a kinetic pseudo-second-order model, the serpentinization rates vary from 3.6x10-6 s-1 to 1.4x10-7 s-1 depending on the olivine grain size. An additional correlation between FTIR spectra analysis and TG measurements is proposed. The mineral replacement reactions frequently observed in natural alteration processes could be a powerful synthesis route to design new porous and/or nanostructured materials

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Experimental study of the carbonation of partially serpentinized and weathered peridotites

Cited by 66 publications

References 70 publications

Intracrystalline Reaction-Induced Cracking in Olivine Evidenced by Hydration and Carbonation Experiments

Intracrystalline Reaction-Induced Cracking in Olivine Evidenced by Hydration and Carbonation Experiments

Opal‐A in the Nakhla meteorite: A tracer of ephemeral liquid water in the Amazonian crust of Mars

Mineral replacement rate of olivine by chrysotile and brucite under high alkaline conditions

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