Friday, February 1, 2013


When a “type” plate tectonic locality and Geowonder is flooded by a dam in Greece.

It’s taken about fifteen years, but the new hydroelectric dam on the Aliakmon River is finished, and now the river valley is slowly filling with energy – yes, energy – the energy contained in the waters of the new lake. Hydroelectric energy is clean energy, no carbon footprint, no nuclear waste, and we’re all for it… right?

The decision to build a dam on a river for energy production is a balance between the needs of the public for ever more (and more, and more) electricity, and that of the value of the lands to be flooded. Yes, there’s the environmental impact, and fish species to be catalogued, and bird species to be counted, and what about the fields the farmers will lose, and the cost of a new bridge that will have to be built?

Few places on earth contain the geologic treasures of the Aliakmon River: for the geologist, it is as spiritual a place as is the Monastery Zavordas on the hill overlooking the river. Our photo shows the hermitage of St Nicanoras dating from about 1528AD. It’s built into a cave in the karst-rich limestone. If things go as planned, the waters of the lake will lap at the base of this ancient chapel. The visual effect, perhaps the soul of the site, will be changed forever.

Along the base of the valley is a geologic heritage site still hardly touched by modern study. Within the valley walls are rocks that show the initial splitting of part of Pangaea leading to the separation of Europe and Africa; within the valley are the rocks born of part of the Tethyan Ocean that filled between the new continents; within the valley are the rocks deformed and emplaced when Africa again closed with Europe, building much of Greece as they collided, and the Alps further north. The last study of these rocks had been in the late 1960’s and early 1970’s, and yes, they did provide several of the critical keys to unlock the theory of plate tectonics.

We were fortunate to be given a grant to work hard for a few years to sample and map and study and discover and document the ancient geology of the river valley by the Public Power Corporation of Greece, the very company in charge of the hydroelectric project. Without their aid, or had the decision been not to build a dam after all so that we had no reason to study the sites so urgently, we never would have been given the funds to conduct a new study of basic research.

So now, it is sad and it is joyous that the valley is finally filling. I said good-bye to the grove of old Platanos trees (called Plane trees in Britain, sycamores in the US and Canada): some of these trees were “geologic” in themselves, with diameters greater than two meters, with ages touching a thousand years. This was hard. I have photos, reports, masters’ and senior dissertations from over 60 researchers. Most of these were students from out of Greece, who we encouraged to do the actual mapping and sampling work, mainly so that a new generation would have a memory of the locality. Among them are some of the finest of “tomorrow’s” geoscientists.

The water is rising… I’ll never be able to cross the footbridge like I did in the 70’s and 80’s, or find that outcrop of dikes I still swear is down there. But – the walls of the valley are steep, were pretty much inaccessible back then so we never could get a good look at them, but now – we’ve got a boat! Imagine that. We hope to be able to float along the walls of Pangaea, of the Tethys, of young Europe. We hope that just maybe we’ll see something along the valley walls that we never were able to see before, and never would see had the dam not been built.

Photo by Robert Sparkes, of the Hermitage of Saint Nicanoras
Some links of interest:

No comments: