Jackson, Ian. Northumberland Rocks — 50 extraordinary rocky places that tell the story of the Northumberland landscape. Newcastle upon Tyne : Northern Heritage, 2021.
The richly illustrated and accessible book series of Northumberland, Cumbria and Durham Rocks are available to purchase from Northern Heritage.
Theme: Heritage and mining
Allenheads is high in the north Pennines. There is a car park in the centre of the village
Allenheads is an old lead mining and smelting village which sits at over 400 metres above sea level in the North Pennines. The lead workings are underground but, in the village and the surrounding countryside, evidence of lead mining and smelting is everywhere, from buildings, to capped old shafts, waste dumps and reservoirs.
It may seem a quiet place now but in the 18th and 19th centuries Allenheads was a busy and thriving town, producing more lead than anywhere else in the region. The veins which contain the lead (the ore mineral is called galena) originate from the injection of hot mineral-rich fluids 290 million years ago. Galena and other minerals, like fluorspar and quartz, originated deep underground. They cooled and crystallised out in cracks and crevices in the surrounding Carboniferous rocks, becoming veins in the limestones and sandstones.
The mine wastes contain lead, zinc and cadmium which are toxic to most plants. But spring sandwort, mountain pansy and Pyrenean scurvy-grass have a genetic tolerance to these elements, and are abundant on some of the former mining sites, although uncommon elsewhere.