Isotopic evidence for dolomite formation in soils

Díaz-Hernández, José Luis; Navas, Ana; Reyes, E.

doi:10.1016/j.chemgeo.2013.03.018

Cited by 31 publications

(23 citation statements)

References 55 publications

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“…The SEM and TEM images show that dolomite is specifically attached to flaky amorphous mixedlayer illite-smectite (Figs 9 and 11), where no biotic evidence has been observed. Considering that the association of dolomite or Mg-bearing calcite with illite/smectite has been previously reported in the geological record, modern lakes and laboratory experiments (D ıaz-Hern andez et al, 2013;Cuadros et al, 2016;Wanas & Sallam, 2016;Nyiro-K osaa et al, 2018;Xu et al, 2018;Liu et al, 2019;Sanz-Montero et al, 2019), it is here assumed that clay minerals can provide favourable surfaces for dolomite precipitation.…”

Section: Role Of the Clay Surfaces On Dolomite Nucleationmentioning

confidence: 93%

“…Recently, the potential effect of clay surfaces (for example, amorphous clay, smectite and palygorskite) on proto-dolomite (Liu et al, 2019) and Mg-rich calcite precipitation (Nyiro-K osaa et al, 2018) has been studied. Based on field observation in soils (D ıaz-Hern andez et al, 2013(D ıaz-Hern andez et al, , 2018Cuadros et al, 2016), evaporative lakes (Wanas & Sallam, 2016) and caves (P erez et al, 2015), as well as laboratory experiments (Xu et al, 2018;Liu et al, 2019) and molecular dynamics (MD) simulations (Sakuma & Kawamura, 2009), it is hypothesized that clay minerals can not only promote the incorporation of Mg 2+ ions into the structure of the rhombohedral carbonate, but also facilitate the local supersaturation of solutes. Moreover, the intimate structural relationship between Mg-bearing calcite and clay minerals in modern calcareous lake indicates that the clay minerals may act as a suitable adsorption surface for primary Ca-Mg carbonate nucleation (Nyiro-K osaa et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

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Nucleation and stabilization of Eocene dolomite in evaporative lacustrine deposits from central Tibetan plateau

Wen

Sánchez‐Román

et al. 2020

Sedimentology

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In past decades, the formation of dolomite at low temperature has been widely studied in both natural systems and cultured experiments, yet the mechanism(s) involved in the nucleation and precipitation of dolomite remains unresolved. Late Eocene dolomitic deposits from core in the upper Niubao Formation (Lunpola Basin, central Tibetan Plateau, China) are selected as a case study to understand the dolomitization process(es) in the geological record. Dolomite formation in Lunpola Basin can be ascribed to a different mechanism forming the large quantities of replacive dolostones in the geological record; and provides a potential fossil analogue for primary dolomite precipitation at low temperature. This analogue consists of an alternation of laminated dolomitic beds, organic‐rich and siliciclastic layers; formed in response to intense evaporation interpreted to take place in a continental shallow lake environment. Mineralogical, textural and stable isotopic evaluations suggest that the dolomite from those dense‐clotted laminated beds is a primary precipitate. At the nanoscale, these dolomitic beds are composed of Ca–Mg carbonate globular nanocrystals (diameter 80 to 100 nm) embedded in an organic matrix and attached to clay flakes. Micro‐infrared spectroscopy analyses have revealed the presence of aliphatic compounds in the organic matrix. Microscopic and elemental compositional studies suggest that clay surfaces may facilitate the nucleation of dolomite at low temperature in the same way as the organic matrix does. The dolomite laminae show values for δ18OVPDB from −3.2 to −1.76‰ and for δ13CVPDB from −2.62 to −3.78‰. Inferred δ18OSMOW values of the lake water reveal typical evaporitic hydrological conditions. These findings provide a potential link to primary dolomite formation in ancient and modern sedimentary environments; and shed new light on the palaeoenvironmental conditions in central Tibet during the Eocene.

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Section: Role Of the Clay Surfaces On Dolomite Nucleationmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Nucleation and stabilization of Eocene dolomite in evaporative lacustrine deposits from central Tibetan plateau

Wen

Sánchez‐Román

et al. 2020

Sedimentology

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“…In closed lakes (Talbot, ), δ 18 O and δ 13 C values of the precipitated carbonate (dolomite) are highly correlated, with negative δ 18 O values reflecting the meteoric origin of these waters (Fig. A; see Díaz‐Hernández et al ., , for a recent example).…”

Section: Discussionmentioning

confidence: 99%

Primary dolomite in the Late Triassic Travenanzes Formation, Dolomites, Northern Italy: Facies control and possible bacterial influence

et al. 2014

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In the late Carnian (Late Triassic), a carbonate-clastic depositional system including a distal alluvial plain, flood basin and sabkha, tidal flat and shallow carbonate lagoon was established in the Dolomites (Northern Italy). The flood basin was a muddy supratidal environment where marine carbonates and continental siliciclastics interfingered. A dolomite phase made of sub-micrometre euhedral crystals with a mosaic microstructure of nanometre-scale domains was identified in stromatolitic laminae of the flood basin embedded in clay. This dolomite is interpreted here as primary and has a nearly stoichiometric composition, as opposed to younger early diagenetic (not primary) dolomite phases, which are commonly calcian. This primary dolomite was shielded from later diagenetic transformation by the clay. The stable isotopic composition of dolomite was analyzed along a depositional transect. The δ13C values range between ca -6‰ and +4‰, with the most 13C-depleted values in dolomites of the distal alluvial plain and flood basin, and the most 13C-enriched in dolomites of the tidal flat and lagoon. Uniform δ18O values ranging between 0‰ and +3‰ were found in all sedimentary facies. It is hypothesized that the primary dolomite with mosaic microstructure nucleated on extracellular polymeric substances secreted by sulphate reducing bacteria. A multi-step process involving sabkha and reflux dolomitization led to partial replacement and overgrowth of the primary dolomite, but replacement and overgrowth were facies-dependent. Dolomites of the landward, clay-rich portion of the sedimentary system were only moderately overgrown during late dolomitization steps, and partly retain an isotopic signature consistent with bacterial sulphate reduction with δ13C as low as -6‰. In contrast, dolomites of the marine, clay-free part of the system were probably transformed through sabkha and reflux diagenetic processes into calcian varieties, and exhibit δ13C values of ca +3‰. Major shifts of δ13C values strictly follow the lateral migration of facies and thus mark transgressions and regressions. © 2014 International Association of Sedimentologists

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“…E) and in the Eldersfield borehole supports evaporative conditions and/or saline groundwaters, whereas the dolomitic nodules in these claystone units may have formed through evaporative dolomitization. At the present day dolomite is typically restricted to saline soils, unless it has been inherited directly from the parent material as authigenic dolomite, but occurrences are known in less evaporitic settings where the soil chemistry is influenced by Mg‐rich parent materials such as serpentinites and by Mg‐rich clay substrates (Díaz‐Hernández et al ., ; Alonso‐Zarza et al ., ; Casado et al ., ). The elevated Mg/Ca ratios required for its formation may reflect the relative depletion in Ca from the precipitation of CaCO 3 and/or Ca sulphates (Goudie, ; Machette, ; Tucker & Wright, ).…”

Section: Mercia Mudstone Group Mudrock Facies Associationsmentioning

confidence: 99%

Dryland continental mudstones: Deciphering environmental changes in problematic mudstones from the Upper Triassic (Carnian to Norian) Mercia Mudstone Group, south‐west Britain

Milroy¹,

Wright

Simms

2019

Sedimentology

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The sedimentology, petrography and mineralogy of the seemingly monotonous Late Triassic Mercia Mudstone Group across the Severn Basin and Bristol Channel region reveals a bipartite division of mudrock facies above and below the Arden Sandstone Formation. Frequently cryptic sedimentary and pedogenic features reveal diverse alluvial, aeolian, playa-lacustrine and pedogenic processes operating at different times, locations and scales probably in response to climate change. The current study found no evidence of significant marine influence in either of the two mudrock facies associations that are described here. Blocky claystones dominate the lower Mercia Mudstone Group (Sidmouth Mudstone Formation), with pedogenic features such as slickensides, mottling, tubules and carbonate/sulphate nodules common and widespread. The claystones are of alluvial/lacustrine origin with subordinate sheet sandstones, themselves overprinted by pedogenic features, reflecting occasional high intensity rainfall events. These facies reflect a seasonal (wet/dry) semi-arid climate favouring development of transformed/neoformed (smectiterich) clay minerals of intrabasinal origin. Massive to weakly stratified silty mudstones dominate the upper Mercia Mudstone Group (Branscombe Mudstone Formation). Commonly conchoidally weathered, locally gypsiferous, but with distinct sedimentary structures scarce, they alternate with subordinate blue-grey laminated silty mudstones. Together they reflect fluctuating hydrological conditions within extensive saline mudflats and ephemeral playa lakes, with laminated facies deposited under subaqueous conditions during more humid phases whereas massive mudstones reflect modification through interstitial growth/dissolution of sulphates and deflation of surface sediments during drier episodes. These facies reflect increased aridity during deposition of the upper Mercia Mudstone Group compared with the lower Mercia Mudstone Group, favouring development of detrital/transformed (illite-chlorite) clay minerals of extrabasinal origin. The described facies associations and the sedimentary fabrics and structures that characterize them, occur widely in the Mercia Mudstone Group across the United Kingdom and comparable facies associations may be anticipated in other fine-grained red bed successions. Recognition of these facies may aid palaeoenvironmental interpretation of such sequences on Earth and, potentially, on Mars also.

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Isotopic evidence for dolomite formation in soils

Cited by 31 publications

References 55 publications

Nucleation and stabilization of Eocene dolomite in evaporative lacustrine deposits from central Tibetan plateau

Nucleation and stabilization of Eocene dolomite in evaporative lacustrine deposits from central Tibetan plateau

Primary dolomite in the Late Triassic Travenanzes Formation, Dolomites, Northern Italy: Facies control and possible bacterial influence

Dryland continental mudstones: Deciphering environmental changes in problematic mudstones from the Upper Triassic (Carnian to Norian) Mercia Mudstone Group, south‐west Britain

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