Effects of early diagenesis on Mg isotopes in dolomite: The roles of Mn(IV)-reduction and recrystallization

Li, Weiqiang; Bialik, Or M.; Wang, Xiaomin; Yang, Tao; Hu, Zhongya; Qingyu, Huang; Zhao, Shugao; Waldmann, Nicolás

doi:10.1016/j.gca.2019.01.029

Cited by 34 publications

(7 citation statements)

References 94 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Different lines of evidence have more recently pointed to dissolved Mn and Zn as potentially important catalyzers of early diagenetic ordered dolomite nucleation (Daye et al ., 2019; Li et al ., 2019a; Vandeginste et al ., 2019). In fresh coastal aquifers, dissolved Mn concentrations are generally <100 nmol kg −1 but are often comparatively enriched in the higher salinity reducing groundwaters (Table 1).…”

Section: Biogeochemical Transformations In the Mixing Zonementioning

confidence: 99%

Biogeochemical reappraisal of the freshwater–seawater mixing‐zone diagenetic model

et al. 2021

Self Cite

View full text Add to dashboard Cite

First proposed nearly half a century ago, the mixing-zone model of dolomitization enjoyed a brief stay in the limelight before falling out of favour. Despite extended past criticism, arguments that build on its current validity are presented and discussed. The coastal mixing zone can be seen as an aquifer system exhibiting marked physicochemical gradients, reflective of the admixture of low salinity freshwater and seawater sources with variable redox potentials. This perspective requires a more holistic look at the mixing zone, not only as a gradient of major element concentrations, but also as the locus of enhanced subsurface redox sensitive reactions that occur at the pore-space scale within a moveable diagenetic front. Combined genomic and isotopic data indicate that an active subsurface biosphere thrives in the mixing zone. This could facilitate Mg 2+ dehydration, generate alkalinity, consume protons and mobilize potentially catalyzing ions (i.e. Mn and Zn), which are all low temperature factors thought to promote dolomite formation from soluble precursors. In the updated model, the advective mix of fluids with contrasting composition modulate a range of biogeochemically induced mineral dissolution and reprecipitation reactions. Biotic and abiotic interactions between these fluids affect carbonate equilibrium and result in dissolution of soluble aragonitic and calcitic phases, while dolomite precipitates (as cement) and neomorphic replacement. The secondary dolomite often exhibits compositional heterogeneity and contentious δ 18 O signatures indicative of re-equilibration. The role of manganese, zinc, intermediate sulphur species and ammonia are far from being fully understood, nor is their fingerprint in ancient deposits. Application of in situ spectroscopic imaging techniques, clumped and metal isotope analyses, as well as a more extended use of traditional approaches, such as sulphur isotopes, are poised to open many opportunities to further explore the biogeochemistry of this diagenetic environment and how it relates to platform dolomitization.

show abstract

Section: Biogeochemical Transformations In the Mixing Zonementioning

confidence: 99%

Biogeochemical reappraisal of the freshwater–seawater mixing‐zone diagenetic model

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…Magnesium isotopes in marine carbonate have been applied to reconstruct the Mg isotopic and chemical composition of ancient seawater (Crockford et al, 2020;Fantle and Higgins, 2014;Gothmann et al, 2017;Higgins and Schrag, 2012;Hu et al, 2019;Li et al, 2015;Li et al, 2019;Pogge von Strandmann et al, 2014). However, the use of carbonates as Mg isotope archive of seawater faces several challenges, including :…”

Section: Discussionmentioning

confidence: 99%

Isotopic responses of magnesium to two types of dissolution-reprecipitation processes for the growth of the double-carbonate mineral norsethite

Liu

Wang

2023

American Mineralogist

View full text Add to dashboard Cite

An important mechanism of carbonate mineral growth is dissolution-reprecipitation, including the transformation of amorphous precursor to crystalline carbonates, and coarsening (ripening) of fine carbonate crystals. However, the mechanistic details of cation exchange associated with carbonate mineral growth via a dissolution-reprecipitation process are still not well understood. In this study, we used Mg isotopes to probe the exchange of Mg between aqueous solutions and norsethite [BaMg(CO 3 ) 2 ] by systematic synthesis experiments. Norsethite is a model double carbonate, with a general formula of AB(CO 3 ) 2 , where A and B stand for two different divalent ions. Formation of norsethite comprised of three stages, including 1) precipitation of barium-magnesium amorphous carbonate, 2) transformation of This is the peer-reviewed, final accepted version for American Mineralogist, published by the Mineralogical Society of America.The published version is subject to change. Cite as Authors (Year) Title. American Mineralogist, in press.

show abstract

“…The concentration of samples matched the in‐house standard to within 10%. The

\delta {}^{26}\mathsf{M}\mathsf{g}

of the in‐house standard was determined as −0.67‰ ± 0.1‰ relative to international standard DSM3 (Li et al., 2011, 2019). All Mg isotopic data were normalized to DSM3 using conventional delta notation to express per thousand deviations from DSM3:

{\delta }^{26}\text{Mg}(\text{{\perthousand}})=\frac{{({}^{26}\text{Mg}/{}^{24}\text{Mg})}_{\text{sample}}-{({}^{26}\text{Mg}/{}^{24}\text{Mg})}_{\text{DSM}3}}{{({}^{26}\text{Mg}/{}^{24}\text{Mg})}_{\text{DSM}3}}\times 1,000

…”

Section: Materials and Analytical Methodsmentioning

confidence: 99%

“…The concentration of samples matched the in-house standard to within 10%. The 𝐴𝐴 𝐴𝐴 26 𝖬𝖬𝖬𝖬 of the in-house standard was determined as −0.67‰ ± 0.1‰ relative to international standard DSM3 (Li et al, 2011(Li et al, , 2019. All Mg isotopic data were normalized to DSM3 using conventional delta notation to express per thousand deviations from DSM3:…”

Section: Mg Isotope Analytical Methodsmentioning

confidence: 99%

Magnesium Isotope Constraints on the Holocene Hydromagnesite Formation in Alkaline Lake Dujiali, Central Qinghai‐Tibetan Plateau

Lin

Knapp

et al. 2023

JGR Earth Surface

Self Cite

View full text Add to dashboard Cite

New Mg isotope data on Holocene hydromagnesite, modern lake and river waters from the Dujiali Lake, central Qinghai-Tibetan Plateau.• A thermodynamic-based box model simulates the behavior of the carbonate system Mg/Ca ratios and Mg isotopes during the evolution of the lake chemistry.• Low-Mg carbonate precipitation may be a common precursor process for driving hydromagnesite precipitation in evaporative lacustrine environments.

show abstract

Effects of early diagenesis on Mg isotopes in dolomite: The roles of Mn(IV)-reduction and recrystallization

Cited by 34 publications

References 94 publications

Biogeochemical reappraisal of the freshwater–seawater mixing‐zone diagenetic model

Biogeochemical reappraisal of the freshwater–seawater mixing‐zone diagenetic model

Isotopic responses of magnesium to two types of dissolution-reprecipitation processes for the growth of the double-carbonate mineral norsethite

Magnesium Isotope Constraints on the Holocene Hydromagnesite Formation in Alkaline Lake Dujiali, Central Qinghai‐Tibetan Plateau

Contact Info

Product

Resources

About