Ayrshire - Lanarkshire - Ailsa
Craig |
South-West Central Scotland including photographs of |
Ayrshire - Lanarkshire - Ailsa
Craig |
South-West Central Scotland including photographs of |
LINKS |
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| Introduction Carboniferous and Devonian (Old Red Sandstone) igneous and sedimentary rocks predominate in this area of central Scotland, covering Ayrshire and Lanarkshire. Coal-mining had an important role in the past. Numerous Tertiary dykes, or "dyke-swarms", trending NW-SE from the Tertiary volcanic centres of Mull, Skye, Rhum and Ardnamurchan on the north-west coast of Scotland also traverse the area. Several of these dykes stretch much farther south into northern England. Indeed, some individual dykes, given their particularly distinctive mineral composition, can also be traced over this length. Scotland's own ophiolite zone - where there is some geological evidence of Scotland and England, once apart, coming together in Palaeozoic times - can be found on the south Ayrshire coast at Ballantrae. |
Mineral Review Mineralization in the area is generally on a small scale. Some old limestone quarries in northern Ayrshire have rendered some specimens of strontianite, barite and celestite with occasional fluorite - something of a Scottish rarity. In the past, coalmines have yielded very good millerite specimens too. An uncollaborated diamond find in these mines was once reported, but is probably an error. Close to the ophiolite zone at Ballantrae, around Lendalfoot and Colmonell, pectolite and chrome spinel occur. The Leadhills mining area, in the southern part of Lanarkshire, is dealt with separately (see link). In Ayrshire, there are several occurences of agates, particularly on the coast. Other smaller, more restricted occurences can be found inland also, including Burn Anne, near Galston. (see agates). |
CHROMITE - (Chrome Spinel) Some sites are on restricted areas (SSSI - Sites of Special Scientific Interest) created to protect early fossil fish occurences in rocks of Devonian age. In Lanarkshire and Ayrshire, in the Lesmahagow, Muirkirk and Sorn area, iron and barite veins have occasionally given specimens of botryoidal hematite of some interest. |
At Hare Hill, near New Cumnock, in southern Ayrshire, there is an occurence antimony mineralization with the main mineral found being stibnite and minor associated secondary minerals. The site is generally referred to as the Knipe Mine. The stibnite (antimony sulphide) occurs as masses of elongated, silvery blades to several centimetres embedded in quartz veins. Some of the stibnite crystals may be altered, either partially or entirely, to stibiconite and small cavities in the quartz veins may also contain micro-crystals of other secondary antimony minerals. At Lugar, a former coal-mining community in south Ayrshire, the less common amphibole group mineral, kaersutite, can be found as embedded crystals in the rock termed lugarite (a type of ijolite), which comprises part of a local Carboniferous sill complex. From a small and insignificant copper trial near Kilbirnie (Swinlees Mine), in Ayrshire, a limited number of specimens of smoky, blue-grey and colourless-white, barite crystals have been extracted. Crystals can attain up to 25mms and over. |
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AGATE - "Fortification
Agate* The Maidens, Ayrshire. |
AGATE - "Vein Agate*
Burn Anne, Galston, Ayrshire. |
HEMATITE - Mannoch Hill
Mine, near Lesmahagow, Lanarkshire |
HEMATITE |
STIBNITE - Knipe Mine, New
Cumnock, Ayrshire. |
STIBNITE - Knipe Mine, New
Cumnock, Ayrshire. |
| AILSA CRAIG - Curling Stones! About 10 miles off the South-West coast of Ayrshire, situated in the Firth of Clyde, is the most impressive feature of Ailsa Craig, an imposing rocky islet, rising over 1100 feet above sea level and with a coastal circumference of around 2 miles. It is the result of volcanic activity that took place during the Tertiary Period and is a "mini-volcano/ plug" composed of granite. The adjacent islet, Litlte Ailsa, is composed, in contrast, of columnar basalt pillars. The impressive cliffs of Ailsa Craig are home to over 10,000 gannets and a few other birds, including the odd puffin. |
In mineral terms, Ailsa Craig has
not yielded any notable specimens, perhaps due to visits
being rather infrequent... Nevertheless, trips by boat
which sail around the island do occasionally occur in the
summer months and are worthwhile for a closer view of
this major natural feature rising from the sea. Ailsa Craig is composed of a riebeckite-arfvedsonite micro granite which was quarried, until around the 1960s, as the supreme quality rock that comprised curling stones, used in the fairly recently incorporated Winter Olympic sport of Curling. The stone was called "crawfordjohn stone" at one time, but the rock now usually composes the outer cladding of curling stones only. This enables them to glide effortlessly and smoothly over the icy surface. |
| Loanhead Quarry, Beith,
Ayrshire (this site is no longer accessible). The most interesting site of recent years in the region is Loanhead Quarry, near Beith, in northern Ayrshire. Good hand specimens of calcite and particularly of botryoidal prehnite were found. The site was also a good location for micromount-collectors (collectors of micro-crystal examples), as several mineral species often occur well-crystallised on a single specimen. |
Examples of several zeolite species, particularly thomsonite and analcime, associated with garnets, hematite and epidote... have made excellent micromounts. The mineralization is associated with a dyke, belonging to one of the "swarms" mentioned earlier and which cuts through Carboniferous-age limestone. In total, around 40 different mineral species have been recorded from the site. |
GROSSULARITE - Loanhead Quarry,
Beith, Ayrshire. right: GROSSULARITE - Loanhead
Quarry, Beith, Ayrshire. |
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THOMSONITE - Loanhead
Quarry, Beith, Ayrshire. |
PREHNITE - Loanhead Quarry,
Beith, Ayrshire. The site is also interesting for the uncommon association of zeolite members with garnet species. Both andratite and grossularite garnet members are present. The rare species, greenockite, has also been recorded at the locality, as well as descloizite and vanadinite micro-crystals. |
| References/ Further Reading Journal of
the Russell Society - UK
Journal of Mines & Minerals - © Minerals of Scotland |
