Are you an EPFL student looking for a semester project?
Work with us on data science and visualisation projects, and deploy your project as an app on top of Graph Search.
Concept
Ikaite
Summary
Ikaite is the mineral name for the hexahydrate of calcium carbonate, . Ikaite tends to form very steep or spiky pyramidal crystals, often radially arranged, of varied sizes from thumbnail size aggregates to gigantic salient spurs. It is only found in a metastable state and decomposes rapidly by losing most of its water content once removed from near-freezing water. This "melting mineral" is more commonly known through its pseudomorphs.
It is usually considered a rare mineral, but this is likely due to difficulty in preserving samples. It was first discovered in nature by the Danish mineralogist Pauly in the Ikka (then spelt Ika) fjord in southwest Greenland, close to Ivittuut, the locality of the famous cryolite deposit. Here ikaite occurs in truly spectacular towers or columns (up to tall) growing out of the fjord floor towards the surface water, where they are naturally truncated by waves, or unnaturally by the occasional boat. At the Ikka Fjord, it is supposed that the ikaite towers are created as the result of a groundwater seep, rich in carbonate and bicarbonate ions, entering the fjord bottom in the form of springs, where it hits the marine fjord waters rich in calcium. Ikaite has also been reported as occurring in high-latitude marine sediments at Bransfield Strait, Antarctica; Sea of Okhotsk, Eastern Siberia, off Sakhalin; and Saanich Inlet, British Columbia, Canada. In addition it has been reported in a deep sea fan off the Congo, and therefore probably has worldwide occurrence. The most recent occurrence has been reported by Dieckmann et al. (2008). They found the mineral ikaite directly precipitated in grain sizes of hundreds of micrometers in sea ice in the Weddell Sea and throughout fast ice off Adélie Land, Antarctica. In addition, ikaite can also form large crystals within sediment that grow to macroscopic size, occasionally with good crystal form. There is strong evidence that some of these marine deposits are associated with cold seeps. Ikaite has also been reported as a cryogenic deposit in caves where it precipitates from freezing carbonate-rich water.
Official source
About this result
This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.
Related lectures (1)
Related publications (4)
Related concepts (5)
Carbonate mineral
Carbonate minerals are those minerals containing the carbonate ion, CO32-. Calcite group: trigonal Calcite CaCO3 Gaspéite (Ni,Mg,Fe2+)CO3 Magnesite MgCO3 Otavite CdCO3 Rhodochrosite MnCO3 Siderite FeCO3 Smithsonite ZnCO3 Spherocobaltite CoCO3 Aragonite group: orthorhombic Aragonite CaCO3 Cerussite PbCO3 Strontianite SrCO3 Witherite BaCO3 Rutherfordine UO2CO3 Natrite Na2CO3 Dolomite group: trigonal Ankerite CaFe(CO3)2 Dolomite CaMg(CO3)2 Huntite Mg3Ca(CO3)4 Minrecordite CaZn(CO3)2 Barytocalcite BaCa(CO3)2 Carbonate with hydroxide: monoclinic Azurite Cu3(CO3)2(OH)2 Hydrocerussite Pb3(CO3)2(OH)2 Malachite Cu2CO3(OH)2 Rosasite (Cu,Zn)2CO3(OH)2 Phosgenite Pb2(CO3)Cl2 Hydrozincite Zn5(CO3)2(OH)6 Aurichalcite (Zn,Cu)5(CO3)2(OH)6 Hydromagnesite Mg5(CO3)4(OH)2.
Monohydrocalcite
Monohydrocalcite is a mineral that is a hydrous form of calcium carbonate, CaCO3·H2O. It was formerly also known by the name hydrocalcite, which is now discredited by the IMA. It is a trigonal mineral which is white when pure. Monohydrocalcite is not a common rock-forming mineral, but is frequently associated with other calcium and magnesium carbonate minerals, such as calcite, aragonite, lansfordite, and nesquehonite. Monohydrocalcite has been observed in air conditioning systems, and in moonmilk deposits in caves, both probably formed from spray of carbonate rich fluids.
Aragonite
Aragonite is a carbonate mineral and one of the three most common naturally occurring crystal forms of calcium carbonate (), the others being calcite and vaterite. It is formed by biological and physical processes, including precipitation from marine and freshwater environments. The crystal lattice of aragonite differs from that of calcite, resulting in a different crystal shape, an orthorhombic crystal system with acicular crystal. Repeated twinning results in pseudo-hexagonal forms.