dolomitti

Dolomitti, or dolomites, are carbonate sedimentary rocks whose primary mineral is dolomite, the calcium magnesium carbonate CaMg(CO3)2. A rock is called dolostone when dolomite is the dominant phase, while dolomitic limestone contains significant amounts of calcite alongside dolomite. These rocks are typically fine to medium-grained and can occur with interbeds of other minerals such as clay, quartz, or iron oxides.

Dolomitization is the key process in their formation. They can form by primary precipitation of dolomite in ancient seas, but more commonly by diagenetic alteration of limestone through magnesium-rich fluids that replace calcium in calcite with magnesium. This transformation often increases rock hardness and changes porosity, influencing karst development and reservoir properties in some regions.

Geographically, dolomitic rocks occur worldwide, including extensive outcrops in North America, Europe, Africa, and Asia. The most famous and geologically significant dolomite exposures are in the Dolomites, a mountain range in northeastern Italy, part of the Southern Alps. The range gives its name to the term dolomiti and to the mineral and rock type itself, named after the 18th-century French geologist Déodat Gratet de Dolomieu.

Uses and significance: dolomites are quarried for crushed stone and aggregate, and in some cases for cement production or magnesium-bearing minerals. They tend to be more resistant to weathering than pure limestone and can form rugged outcrops, cliffs, and extensive karst landscapes. In hydrogeology, dolostones can act as aquifers with distinctive flow characteristics.