The metastable mineral – ikaite
Sometimes in near frozen sea water, in places where lime rich groundwater seeps in the seawater, congregations of an unusual mineral are formed. This mineral – ikaite – is hexahydrate of calcium carbonate, with the chemical formula CaCO3·6H2O.
Ikaite can exist only in certain conditions – in cold water. If it is rised out of the water or is placed in a warmer water, it quickly decomposes.
Nowadays ikaite or its traces are discovered in seas worldwide – not very frequently… but people don’t dive to the bottom of cold seas in too many places anyway. Thus it is possible that this mineral is fairly common.
How ikaite was discovered
Greenland has thousands of fjords and most of these fjords are rarely visited by people. There should happen something special for people to observe something unusual on the bottom of such fjord. After all: water there is cold and for most part of the year – frozen!
Ikka Fjord is located in the south of Greenland – in area which was settled by Norsemen in the 10th – 14th centuries.
In 1799 near this fjord was discovered deposit of cryolite – the only industrial mine of this rare mineral in the world. This mineral turned out to be quite valuable – it was used to make caustic soda, yellow fireworks, insecticide. Cryolite was valuable source of aluminium – metal, which in the 19th century was rare and very expensive. Later it was discovered that it can be used to extract aluminium from much more common ore – bauxite.
Thus the only cryolite mine in the world was very valuable. Small town of miners – Ivittuut – developed at the mine and was inhabited until 1980ies, when mine was exhausted and production of artificial cryolite mastered.
Weird skerries of Ikka Fjord
During their free time people from the mining town investigated the area around Ivittuut – thus it was known better than most of the other Greenland.
In 1950ies – 1960ies miners learned from Inuit people that some 5 km from the mine, in the far end of Ikka Fjord – in Ikka Bund are located weird skerries. The bottom of the boats sometimes was hitting these white rocks in the middle of fjords.
According to the local legends these are drowned Norsemen who escaped from their village after brawl with Inuit people and fell through the ice in the fjord. These Norsemen stand in the water up to this day, with streched hands and long beards…
Samples of these unusual rocks were brought to Copenhagen and analysis did not show anything unusual – it seemed that these rocks were just pieces of calcite (very common mineral).
In August 1962 this site was visited by geologists (Hans Pauly) and navy diver. Diver reported that weird geological formations – white, uneven columns rise from the bottom of the fjord. Many of these columns almost reached the surface of the fiord.
Discovery of natural calcium hexahydrate
Divers took samples of this material – and it was weird: in a few hours time these rocks disintegrated into a wet powder. Then samples were taken repeatedly and brought in refridgerator to Copenhagen.
Further analysis showed that a new mineral has been discovered – a natural calcium hexahydrate. It was named after the locality of its discovery – Ikka Fjord.
These spectacular columns have been formed by submarine springs which are issuing from the bottom of Ikka Fjord. The water of these springs is saturated with carbonates and phosphates from the nearby rocks. As the springwater is mixing with seawater, ikaite is formed and sedimented. Springwater continues to flow – and ikaite is further deposited, gradually forming a natural column.
If Ikka Bund would be deeper, the columns would be taller. But now their height is limited by the surface of the fjord, by ice which covers the fjord in November – May and in summer – by the 2 m thick layer of freshwater over the seawater.
Ikka column garden
Over the area of approximately 0.5 x 2.5 km in the fjord were counted some 600 ikaite columns which are 1 – 18 m tall and have a diameter of 1 to 10 m. Larger columns seem to be lined along fault lines. Some spectacular columns are just 0.1 – 0.15 m in diameter and rising up to 8 m tall.
Some columns at the top have flat, wide tops similar to mushrooms – most likely formed by dissolution of ikaite by freshwater.
Experiments have shown that columns are growing fairly fast – some 0.5 m per year.
Another spectacular feature is the rich sea life around the columns. Life is sturdy – in spite of cold water and darkness under the ice cover live numerous interesting creatures – sea stars, anemones, urchins and others.
Since 2000 Ikka Fjord is a protected natural territory.
- Hans Pauly. "Ikaite", a New Mineral from Greenland. Arctic. Vol.16, No.4. (Dec., 1963), pp. 263-264.
- Bjørn Buchardt, Carsten Israelson, Paul Seaman and Gabrielle Stockmann. Ikaite Tufa Towers in Ikka Fjord, Southwest Greenland: Their Formation by Mixing of Seawater and Alkaline Spring Water. Journal of Sedimentary Research. January 2001, vol.71, pp. 176-189.
|Coordinates:||61.1912 N 48.0279 W|
|Categories:||Rare natural materials, Rock spires, Subaquatic springs|
|Address:||North America, southern part of Greenland, Sermersooq, some 5 km east from Kangilinnguit, far end of Ikka Fjord – Ikka Bund|
|Area:||˜ 600 ha|
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