Evidence of the production and dissolution of carbonate phases in bentonite formations

The production and dissolution of carbonates can occur in natural and artificially compacted bentonite soils. The formation of carbonate nodules was studied in bentonite and Pleistocene formations. In samples from a bentonite mine, small carbonate nodules were found clustered around silica particles. Dissolution studies on calcite, dolomite, siderite and magnesite were performed. Dissolution rates were in the increasing order of magnesite, siderite, dolomite and calcite. The production and dissolution of carbonates can change the microstructure of the matrix which subsequently affects its pore size and permeability. It is also possible that the formation of a carbonate crust can build a strong structure and seal the pores. To overcome these challenges, the characteristics of carbonate and similar minerals should be taken into account.