Carbonates: An overview of recent TEM research

Carbonates are abundant minerals on the Earth's surface. Carbonate rock formations constitute up to 16% of the exposed continental crust and form large oil and gas reservoirs. Different organisms are able to produce carbonate skeletons and structures through biomineralization, primarily in marine environments. Carbonates are secondary products of the weathering of primary silicate minerals, thereby contributing to the regulation of atmospheric CO2, Earth surface T and climate over geological time. Carbonates form economic mineral deposits, and are key raw materials in the chemical and cement industries, as well as in many technological and industrial processes. Carbonate rocks such as limestone, dolostone and marble have been used ubiquitously as building stones. The discovery of carbonates in meteorites, some of them coming from Mars, shows that their importance is beyond the Earth's limits. Understanding carbonate mineral formation, dissolution, texture and microstructure, as well as its transformation, decomposition and deformation is critical in all the above-mentioned geological, biological, industrial and technical aspects. Transmission electron microscopy (TEM) is a key analytical tool which has provided valuable information on all these issues. Here we review recent progress in the study of carbonate minerals using TEM.