The dolomite is a Sedimentary rock carbonated made up from at least 50% of Dolomite. It is about a double magnesium and calcium carbonate, of chemical composition CaMg (CO3) 2 , which crystallizes out of prisms losangic (rhombohedrons). Dolomite is thus a sedimentary rock made up mainly of dolomite (between 90 and 100%) and of calcite, which do not have the same density (dolomite: 2.87; calcite: 2.71), playing a fundamental role in the erosion of the rock.
It does not make cold effervescence with the Hydrochloric acid diluted with 10% like the Calcaire. Dolomite is insensitive with the Gélifraction, and thus did not undergo the gel of the Quaternaire.
Its name comes from the Géologue French Déodat Gratet de Dolomieu.
According to the genesis of dolomites one distinguishes:
- primary dolomites resulting from the dolomite precipitation in coastal lagoons of the hot countries.
- secondary dolomites resulting from the replacement of the Calcite by dolomite (process of Dolomitization).
LayerOne finds great dolomite formations in the Trias the Alps, in particular the Dolomites in the north of the Italy. One observes also landscapes known as " ruiniformes" on the Causses (Larzac for example) of which some are famous: the Circus of Mourèze in the Herault, Montpellier-the-Old man on the Black Causse, or Nimes-the-Old man on the Causse Méjean; it is about Lapiaz giant dug by erosion in dolomite, true labyrinths of rocks of which some affect sometimes eccentric forms: anthropomorphic arches, silhouettes, faces, etc
Provencaux solid masses: Alpilles with the Beam-of-Provence. The chain of central star: rammer of the king, mountain of Baou Traouquas, massive of the Holy-Balsam locally to the secondary solid mass of Lare; plate of Agnis and white Sioux, mountain of Loube, Bars of Cuers, Large Bessillon etc
The vegetation on dolomitic ground is characterized in the south of France by the arborescent heather, the cane-apple bush, the cistus of Montpellier, the maritime pine…
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