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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.
Calcite is found in many different areas in the United States. One of the best examples is the Calcite Quarry in Michigan. [23] The Calcite Quarry is the largest carbonate mine in the world and has been in use for more than 85 years. [23] Large quantities of calcite can be mined from these sizeable open pit mines.
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 ...
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]
The California National Guard has sent 200 personnel to help fight four major fires in L.A. County, and federal and out-of-state agencies are also pledging help. L.A. firefighters are spread thin ...
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″.