Watery Edges tracking a river across Andalucia
Tim Sharp
That’s an interesting notion, I thought, in the call for articles. The other terms – shorelines, seafront promenades, landing sites, docks and ports – faded into the background, so defined, so real. ‘Watery edges’ had just the right amount of mental space for me to imagine a line meandering along a coast line, Andalusia, say, and having encountered a river, following it inland to its source before crossing to the other bank and heading back to the estuary to intersect with the coast again. More or less what we were doing. Of course, you say, your line would have to include all the tributaries too. It would, and it would be almost endless as it wound its way round the globe, all-encompassing, you could say. So let us begin at an arbitrary point and try to link up with these thoughts. A hilly landscape, dry, scrubby, not very fertile but in parts it supports stone pines. A drop of water falls from the sky. Then a million. The waiting plants suck them up, the thirsty earth absorbs them, then lets the surplus sink. It soaks into the depths, leaving the kingdoms of now, of decades and centuries for the realms of aeons . The rest is run-off and it hurries to join water that has found its way back to the sunlight as a stream bearing the mineral memory of its journey. If that flow is joined by others it becomes a river heading ever downwards, back to the sea. If such a river passes over granite, its waters will be soft; if over limestone, hard. Let me be more specific about where we are: the Iberian Pyrite Belt, in the south-west of the peninsula, running from Setubal near the Rio Sado estuary on the Atlantic, in a south- east direction across Portugal, and then east across western Andalusia to a point north of Seville. The belt is about 250 kilometres long and twenty to forty kilometres wide. Many rivers run here. If, over time, our rivers seep and cut their way through geological layers, they may encounter the results of very ancient hydrothermal activity on an even more ancient seabed, picking up iron, sulphur and other heavy metals. If one of them turned a very distinct red and become highly acidic it might well be called Rio Tinto, the red river of Andalusia, a region bounded in the south by the Gulf of Cadiz into which it empties. But the Rio Tinto is not the only river here. Just eighteen kilometres further north a sister stream emerges in the Sierra de Aracena to become Rio Odiel with which it shares its geological parentage. Along with their various tributaries, they flow through the pyrite belt — one of the largest sulphide deposits in the world. There are many more: Rio Guadiana which acts as the border between Spain and Portugal; Rio Agrio, a tributary of Rio Guadiamar which is itself a tributary of the Guadalquivir with its estuary in the Gulf of Cadiz. The Iberian pyrite belt contains sulphur, copper, gold, silver and tin, and has been been exploited since humans learned to make fire by striking iron pyrite against flint. Anything other than surface mining only began about 4,000 years ago: it
A stone pine landscape, Huelva province, Andalusia
Roman bridge over Rio Tinto at Niebla.
all images Tim Sharp
was the Romans who first mined the area systematically, with deep tunnels and using tiered waterwheels to drain the shafts and galleries. In the four centuries of their Iberian presence, they operated over forty mines in the pyrites belt, in one case turning a hill into a deep open pit. The abandoned Tharsis pit.
20 on site review 49 :: shorelines
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