Application of geochemical and groundwater data to predict sinkhole formation in a gypsum formation in Manitoba, Canada

Moore, K. R.; Holländer, Hartmut; Basri, Mohamed El; Roemer, M.

doi:10.1007/s12665-019-8188-1

“…In contrast, once the quasi-stationary regime of solutal convection characterized here has been reached, the erosion velocity remains constant, which implies a significantly higher amount of dissolved material. This point is crucial specifically in the case of the development of dissolution cavities in gypsum strata which can lead to the appearance of sinkholes at the surface [6,[62][63][64].In nature, an external flow could inhibit the solutal convection. If the velocity of an externally forced flow, in the boundary layer, is larger than the characteristic velocity D/δ, the external flow would overcome the solutal convection to transport the solute.…”

Section: Discussionmentioning

confidence: 99%

Solutal convection induced by dissolution

Philippi

¹

,

Berhanu

²

,

Derr

³

et al. 2019

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The dissolution of minerals into water becomes significant in geomorphology, when the erosion rate is controlled by the hydrodynamics transport of the solute. Even in absence of an external flow, dissolution itself can induce a convection flow due to the action of gravity. Here we perform a study of the physics of solutal convection induced by dissolution. We simulate numerically the hydrodynamics and the solute transport, in a 2D geometry, corresponding to the case, where a soluble body is suddenly immersed in a quiescent solvent. We identify three regimes. At short timescale, a concentrated boundary layer grows by diffusion at the interface. After a finite onset time, the thickness and the density reach critical values which starts the destabilization of the boundary layer. Finally, the destabilization is such as we observe the emission of intermittent plumes. This last regime is quasi-stationnary: the structure of the boundary layer as well as the erosion rate fluctuate around constant values. Assuming that the destabilization of the boundary layer occurs at a specific value of the solutal Rayleigh number, we derive scaling laws both for fast and slow dissolution kinetics. Our simulations confirm this scenario by validating the scaling laws both for onset, and the quasi-stationary regime. We find a constant value of the Rayleigh number during the quasi-stationary regime showing that the structure of the boundary layer is well controlled by the solutal convection. Finally, we apply the scaling laws previously established to the case of real dissolving minerals. We predicts the typical dissolution rate in presence of solutal convection. Our results suggest that solutal convection could occur in more natural situations than expected. Even for minerals with a quite low saturation concentration, the erosion rate would increase as the dissolution would be controlled by the hydrodynamics.

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“…The dissolution rate expression used is derived from non-linear mixed reaction-transport kinetic theory that considers the evolution of extensive fissures in karst aquifers under normal hydrogeological conditions. Similar rate laws are employed in numerical modelling approaches to study gypsum dissolution underground and the induced geomechanical consequences at the surface, such as depressions, subsidence or sudden collapses [23][24][25].…”

mentioning

confidence: 99%

Identification of the parameters affecting the in situ dissolution process of natural gypsum

Zaier

¹

,

Billiotte

²

,

Windt

³

et al. 2022

Preprint

0

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This study aims at quantifying the parameters involved in water-gypsum interactions to better assess of the development of dissolution cavities in areas where gypsum is present at depth.The effect of erosion and particle transport on gypsum dissolution is first determined by an original leaching set-up under constant flow including a collector of the released grains. Different types of natural gypsum facies are tested, impure alabaster, sacharoidal, clay/carbonate matrices ones. The flow of released particles is globally low and mostly composed of insoluble grains. The distribution of insoluble at the water/solid interface has a significant impact on the dissolution. The effects of the mineralogy of the impurities present in gypsum deposits and of the groundwater chemistry are then investigated by geochemical modeling. These findings are then applied to in situ conditions. The use of a simple criteria such as dissolved sulfate content or electrical conductivity is not sufficient. An effective recession rate is derived from the porosity, the insoluble contents and the groundwater saturation index obtained from its chemical analysis.

show abstract

“…The dissolution rate expression used is derived from non-linear mixed reaction-transport kinetic theory that considers the evolution of extensive fissures in karst aquifers under normal hydrogeological conditions. Similar rate laws are employed in numerical modelling approaches to study gypsum dissolution underground and the induced geomechanical consequences at the surface, such as depressions, subsidence or sudden collapses [23][24][25].…”

mentioning

confidence: 99%

The impact of common impurities present in gypsum deposits on in situ dissolution kinetics

Zaier

¹

,

Billiotte

²

,

Windt

³

et al. 2022

Environ Earth Sci

2

0

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This study aims at quantifying the parameters involved in water-gypsum interactions to better assess of the development of dissolution cavities in areas where gypsum is present at depth.The effect of erosion and particle transport on gypsum dissolution is first determined by an original leaching set-up under constant flow including a collector of the released grains. Different types of natural gypsum facies are tested, impure alabaster, sacharoidal, clay/carbonate matrices ones. The flow of released particles is globally low and mostly composed of insoluble grains. The distribution of insoluble at the water/solid interface has a significant impact on the dissolution. The effects of the mineralogy of the impurities present in gypsum deposits and of the groundwater chemistry are then investigated by geochemical modeling. These findings are then applied to in situ conditions. The use of a simple criteria such as dissolved sulfate content or electrical conductivity is not sufficient. An effective recession rate is derived from the porosity, the insoluble contents and the groundwater saturation index obtained from its chemical analysis.

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Application of geochemical and groundwater data to predict sinkhole formation in a gypsum formation in Manitoba, Canada

Cited by 5 publications

References 83 publications

Solutal convection induced by dissolution

Solutal convection induced by dissolution

Identification of the parameters affecting the in situ dissolution process of natural gypsum

The impact of common impurities present in gypsum deposits on in situ dissolution kinetics

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