Monday, 29 April 2013

Nullipore or coralline sand from Craig, near Plockton and Claigan, near Dunvegan, Scotland

Nullipore or coralline sand from Craig, two miles east of Plockton, near Kyle of Lochalsh. In certain areas the calcareous alga Lithothamnion calcarreum flourishes in great abundance and broken fragments of the thallus form dazzling, creamy-white beaches which are composed almost exclusively of this material.
BGS image ID: P527777
Nullipore or coralline sand from Craig, two miles east of Plockton, near Kyle of Lochalsh. In certain areas the calcareous alga Lithothamnion calcarreum flourishes in great abundance and broken fragments of the thallus form dazzling, creamy-white beaches which are composed almost exclusively of this material.  Lithothamnion calcarreum lives in the upper and lower sub-littoral zone. In places they have been dug for agricultural lime. Colonies have been found elsewhere in Scotland, especially on Skye near Dunvegan, particularly from three bays the largest of which is Camus Ban north of Rubha na Gairbhe.

British Geological Survey Petrology Collection sample number MC 7553.


Nullipore or coralline sand probably from the shore at Claigan, about four miles north of Dunvegan Castle. Coralline or nullipore sand is found in three small bays near Claigan. It consists of broken fragments of the calcareous algae Lithothamnion calcarreum.
BGS image ID: P527775
Nullipore or coralline sand probably from the shore at Claigan, about four miles north of Dunvegan Castle. Coralline or nullipore sand is found in three small bays near Claigan. It consists of broken fragments of the calcareous algae Lithothamnion calcarreum. It forms dazzling white beaches. The sand is coarsely granular and the fragments composing it have a marked coral-like appearance. The quantity varies somewhat from year to year depending on the incidence of storms. Camas Ban, the most southerly of the three bays, is accessible by road. Published figures (from 1956) estimated a minimum of 2,500 tons is available at low tide, possibly less than 1,000 tons at high tide. The other two beaches are inaccessible by road; the minimum quantity available at low tide from the two beaches would probably amount to about 5,000 tons. The sand has been used locally for agricultural purposes. Analysis showed this sand (S.L. 6) to contain 84.32 per cent calcium carbonate and 10.35 per cent magnesium carbonate.

British Geological Survey Petrology Collection sample number MC 7551.

Bob McIntosh

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