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Photomicrograph of a thin section in cross and plane polarised light: the brighter mineral grains in the picture are dolomite, and the darker grains are calcite. Dolomite (/ ˈ d ɒ l. ə ˌ m aɪ t, ˈ d oʊ. l ə-/) is an anhydrous carbonate mineral composed of calcium magnesium carbonate, ideally CaMg(CO 3) 2.
The texture is quite similar to the carbonate-glimmerites, excluding the areas, where the carbonates and micas are banded and occur as their own phases. The average mineral composition is 46% phlogopite, 22% dolomite, 19% calcite, 9% apatite and 4% amphiboles, although the amount of calcite should be higher than the one of dolomites. [25]
Dolomitization is a geological process by which the carbonate mineral dolomite is formed when magnesium ions replace calcium ions in another carbonate mineral, calcite.It is common for this mineral alteration into dolomite to take place due to evaporation of water in the sabkha area. [1]
Thin section of apatite-rich carbonatite in cross polarised transmitted light. The sample is from Siilinjärvi apatite mine . Carbonatites may contain economic or anomalous concentrations of rare-earth elements (REEs), phosphorus , niobium – tantalum , uranium , thorium , copper , iron , titanium , vanadium , barium , fluorine , zirconium ...
Degrading concrete has been the focus of many studies and the most obvious sign is calcium-rich leachate seeping from a concrete structure. [5] [6] [7]Calthemite stalactites can form on concrete structures and "artificial caves" lined with concrete (e.g. mines and tunnels) significantly faster than those in limestone, marble or dolomite caves.
Thin section photomicrograph of a carbonate mudstone in plane polarised light. The Dunham classification system for carbonate sedimentary rocks was originally devised by Robert J. Dunham (1924–1994) [ 1 ] in 1962, [ 2 ] and subsequently modified by Embry and Klovan in 1971 [ 3 ] to include coarse-grained limestones and sediments that had been ...
It was first recognized as a distinct species by Wilhelm von Haidinger in 1825, and named for Matthias Joseph Anker (1771–1843) of Styria, an Austrian mineralogist. [3]In 19th-century mineralogy, as well as in mining and among geologists, ankerite and its close analogues from the dolomite series were more often known by the capacious, expansive name of ″brown spar″.
Biooosparite with calcitic ooids and sparry calcite cement; Carmel Formation, Middle Jurassic, of southern Utah, USA. Thin section of a biopelsparite showing a geopetal structure consisting of peloid sediment and sparry calcite cement in a recrystallized bivalve shell; Bird Spring Formation ( Carboniferous ) of southern Nevada, USA.