Mining, minerals, & marshes in the Duddon Estuary
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The Duddon Estuary is a landscape shaped by geological forces, glaciers, then finally, man, here at Hodbarrow you will see evidence of both, rock formations dating back millions of years and a 19th century unusual lagoon formed for heamatite iron mining.
With the Lakeland fells behind, the Duddon estuary presents an ever changing view, the bedrock was laid odwn millions of years ago, when the Holcene glaciers retreated, melting 10,000 years ago, they left behind thick layers of sediment, powerful ocean tides have then sculpted a scene of mudflats,dunes, water and salt marshes which run right along the coast towards Broughton in Furness, the salt marsh landscape is thought to look as it would have 10,000 years ago.
At the coordinates given for the cache, you will find your self on a small remote beach looking out into the bay, the rock that you will be standing on and that is all around you is Carboniferous limestone, but what is that exactly ?
Carboniferous limestone is a sedimentary rock made of calcium carbonate. It is usually light-grey in colour, and is hard, gripy when dry but slippery when wet. It was formed in warm, shallow tropical seas teeming with life. The rock is made up of the shells and hard parts of millions of sea creatures, encased in carbonate mud. Fossil corals, brachiopods and crinoids are very much in evidence as components of Carboniferous limestone.
This limestone area of the beach that leads into the sea has charachteristics of a limestone pavement hoever is has been eroded by the sea and now has many unusual shapes which now form rock pools whereas more inland these 'grikes' more than likely would house a habitat of their own, which encourages the growth of shade-loving ferns and other fauna.
Interestingly the limestone here also contains quartz, it can be seen as veins running through the rock and also clusters of it protruding through the limestone on various parts of the beach, Quartz is an essential constituent of granite and other felsic igneous rocks. It is very common in sedimentary rocks such as sandstone and shale and is also present in variable amounts as an accessory mineral in most carbonate rocks. Quartz wasn't the only thing to have been discovered in Hodbarrow though... in the 18th century high grade Haematite ores with an iron content on 40% - 62% were discovered and that led to Hodbarrow going from a quiet area to a mining giant
The Hodbarrow Iron mine
The Hodbarrow mine evolved to become one the most productive and important haematite mines in the world, iron ore mining began in 1880 and with it came the start of an epic battle with the sea, after 2 unsucessful attempts to sheild the mines from the sea by using barriers a huge engineering project was started to build what is now known as the 'Hobarrow outer wall' this wall creating the 'lagoon' you see here today cost £600,000, took five years to build and when it was finished in 1905 it was considered to be a work of unusual and exceptional kind.
The mines closed in 1968 but the barrier still stands as a poignant reminder of the industrial past, the are has now been reclaimed by nature and is now a reserve for wildlife including the increasingly rare Natterjack toad
You will have to visit three locations to complete the tasks, all showing you different things relating to this cache, the locations are close together and you can pick up some traditional caches en route
To claim this Earthcache please complete the following tasks:
1. At the given coordinates for the cache take a photo of you or your GPS on the Limestone beach.
2. At the same place identify and take a photo of an example of quartz coming through the limestone, please describe the colour of the quartz you discover
3. At 54.11.571 003.15.382 you will see an information board, what is being tipped at Millom in the picture on the left ?
4.At 54.11.417 003.16.039 you will be stood on the sea barrier by the large lighthouse, there is an information board, what happened in 1924?
Please post your photo's in your log and email the answers to me directly, any logs without this information may be deleted
Have fun exploring this fantastic area
PLEASE NOTE: I receive a very high number of Earthcache emails, I can’t reply to them all otherwise I’d be doing nothing else all day, as has always been the case there is no need to await a reply from me regarding your answers…. However due to numerous people thinking they can just log these caches without emailing any answers, and/or completing the required tasks these will be picked up, and the logs will be deleted without further communication. To facilitate this Please email your information either before, or AT THE SAME TIME OF LOGGING THE CACHE, Thanks.
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