As a summer project before starting the degree we were asked to dig up some local clay for further testing, analysing and experimenting with.
Also undertaking a short research into how the area was used before for production; socio-historic timeframe, history and geology.
I dug up my clay in one of my favourite explorational places around Cardiff, where I tend to go on a short bicycle trip to relax and explore.
Fforest Fawr with the Castle Coch nesting nearby, above the village of Tongwynlais.
Landscape – Site of Specific Scientific Interest – the woods surrounding the Castle Coch know as the Taff Gorge complex, are amongst the most westerly natural beech woodlands in the British Isles. … The area has unusual rock outcrops, which show the point where Devonian Old Red Sandstone and Carboniferous Limestone beds meet.
In the area of Tongwynlais, coal, limestone and iron ore deposits could be found in close proximity to each other, allowing creation of early industrial landscape for iron production.
The mine entrances known as “The Three Arches” (or The Three Bears Cave) descending of up to 20 metres deep into the thick bedded limestone, is still visible, but fenced. The walls of the cave reveal how the mines were carved, with cylindrical features; former drill holes for dynamite to blow open the seam.
The iron works ceased in 1879 due to competition of surrounding towns using cheaper methods of extraction.
Looking at British Geological Survey’ viewer, I could pinpoint the location of where I dug the clay substance and look at the geological composition of the area.
Unfortunately, there’s no specific information on surface composition of exactly where I dug the clay; but “Alluvium – clay and slit,…” deposits very close-by in the village.
The bedrock of the forest area is sedimentary Dolomitic Limestone, formed about 326-359 million years ago.
Equipped with only a small frog trowel, big buckets and a dear friend driving me to the chosen location, I enthusiastically set out for the investigational task.
With the advice from the letter stating the summer project, we’ve found a small stream in the forest. Trying to dig approximately 40cm deep before excavating the clay proved to be challenging without a proper spade. So after about 20cm of excavation I couldn’t go any deeper so collected any, at least a bit plastic seeming substances.
Back home I spread the mud substance, removed any larger rocks, twigs and leaves and let it dry. In the process a strong smell of mainly sulphur creeped across my house.