Dolomite and dolomitization model - a short review

Abstract

Worldwide carbonate rocks are occurring abundantly. These carbonate rocks are a major class of sedimentary rocks group. Carbonate are sedimentary rocks formed at (or near) the Earth surface by precipitation from solution at surface temperatures. The two broad categories are limestone, which is composed of calcite or aragonite (different crystal forms of CaCO3) and dolostone, which is composed of the mineral dolomite (Ca Mg (CO3)2). Dolomite is not a simple mineral; it can have a variety of origin, can form as a primary precipitate, a diagenetic replacement, or as a hydrothermal/metamorphic phase, all that it requires is permeability, a mechanism that facilitates fluid flow, and a sufficient supply of magnesium. Dolomite can also form in lakes, on or beneath the shallow seafloor, in zones of brine reflux, and in early to late burial settings. It may form from seawater, from continental waters, from the mixing of basinal brines, the mixing of hypersaline brine with seawater, or the mixing of seawater with meteoric water, or via the cooling of basinal brines. Potential fluid sources are seawater and subsurface fluid of marine and/or meteoric origin: and addition Mg could be released from high-Mg calcite and smectite clays. The only abundant source of Mg2+ ions for early diagenetic surface and near-surface dolomitization is seawater. Dolomitization also creates new crystals, with new rhomb growth following the dissolution of less stable precursors. Dolomitization model and formation depend on the source dolomitization site and lastly, there must exist a favorable condition for a chemical reaction. One particular type of dolomite which may be a cement or a replacement is baroque dolomite, also called 'saddle' or 'white sparry' dolomite and known to mineral collectors as pearl spar. It is characterized by a warped crystal lattice.

On the Use of Dolomite as a Mineral Filler and Co-Filler in the Field of Polymer Composites: A Review

“…It may be present in lakes or beneath shallow seafloors, in early to late burial settings [ 15 ]. Dolomite can occur via two possible mechanisms, direct precipitation and through the dolomitization process, in which calcite dissolves, supplying Ca 2+ ions, followed by the precipitation of dolomite from a solution rich in Mg 2+ ions [ 15 , 16 , 42 ]. Some dolomites come from the replacement of the pre-existing limestone through the dolomitization process [ 15 ].…”

“…Dolomite can occur via two possible mechanisms, direct precipitation and through the dolomitization process, in which calcite dissolves, supplying Ca 2+ ions, followed by the precipitation of dolomite from a solution rich in Mg 2+ ions [15,16,42]. Some dolomites come from the replacement of the pre-existing limestone through the dolomitization process [15]. Dolomite is one of the most abundant carbonate rocks after calcite.…”

“…It contains a large deposit of high-purity calcium magnesium carbonate and owns a unique geological structure due to the composition of two different kinds of sedimentary rocks, dolomitic and volcanic. The presence of volcanic sediment makes dolomite more resistant to weathering and endows it with hardness [ 14 , 15 , 16 ]. However, it was found that the use of dolomite in its raw form could not improve the mechanical properties of the polymeric matrices.…”

The Mechanical and Thermal Properties of Poly(ethylene-co-vinyl acetate) (PECoVA) Composites with Pristine Dolomite and Organophilic Microcrystalline Dolomite (OMCD)

“…Dolomite is a sedimentary carbonate rock which consists of calcium (Ca), magnesium (Mg), carbon (C) and oxygen (O 2 ) elements. The structure of dolomite is in a crystal lattice form and consists of three layers, where the alternating layers of calcium and magnesium are separated by a carbonate (CO 3 ) layer which gives a chemical formula of Ca·Mg(CO 3 ) 2 [ 6 ]. High quality dolomite has been discovered in Perlis, Malaysia in 1985 [ 7 ].…”

Novel Nano-Fe2O3-Co3O4 Modified Dolomite and Its Use as Highly Efficient Catalyst in the Ozonation of Ammonium Solution

“…Dolomite is a mineral clay composed of calcium magnesium carbonate CaMg(CO 3 ) 2 [9]. However, raw dolomite cannot be used as adsorbent and catalyst due to its low surface and high impurities.…”