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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]
The magmatic origin of carbonatite was argued in detail by Swedish geologist Harry von Eckermann in 1948 based on his study of Alnö Complex. [5] [6] It was however the 1960 eruption of Ol Doinyo Lengai in Tanzania that led to geological investigations that finally confirmed the view that carbonatite is derived from magma.
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 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 ...
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.
Mineral symbols (text abbreviations) are used to abbreviate mineral groups, subgroups, and species, just as lettered symbols are used for the chemical elements.. The first set of commonly used mineral symbols was published in 1983 and covered the common rock-forming minerals using 192 two- or three-lettered symbols. [1]
Often the cone-in-cone will be found as features of calcite layers within a shale, [5] and rarely within a dedolomite (calcitized dolomite). [6] Cone-in-cone structures should not be confused with either shatter cones such as are produced by meteorite impacts, or with shear cones like those developed in coals. Both these structures differ from ...