Article from the August 2002 issue of
UP A VOLCANO BY BIKE
The death of a very special Jack Russell Terrier who had carved out his own particular niche in my existence and the frustration of being two weeks behind the OU recommended schedule for S369, and four weeks behind my own, gave my annual bike trip with Sigi and Christian something of a schizophrenic touch. I was glad to ‘get away’ from it all, but I couldn’t really afford the time.
This year we had a fourth tourist with us, Rolf, who I had hoped, would have a sobering influence. I can’t say that he succeeded, however being something of a connoisseur, he helped to ensure that the food and drink consumed wherever we stayed, were of the highest standard available. Also, the tour was something of a trip into the unknown, through Bavaria, the Czech Republic, Saxony and Thueringia before reentering Bavaria.
Geographically this meant overcoming the Bohemian Forest to get to Marienbad and Carlsbad, finding a way across the Erzgebirge to reach Saxony and a way through the Vogtland Hills and Thueringian Forest to get back onto Bavarian soil. This all turned out at least a number too much for four enthusiastic, but nevertheless geriatric bikers, however, the Czech Railways and the ‘Vogtland Sprinter’ meant that we did re-emerge again. Geologically, the whole area is something of an igneous and metamorphic paradise. The rocks vary from gabbro, diorite and granites, intruded during the late Proterozoic and early Palaeozoic and gneiss formed during the same period and through to the Ordovician. During the Variscan Orogeny, large amounts of granite were intruded and the metamorphosis of the earlier igneous rocks and the sediments formed from them resulted in the region being very rich in ores ranging from tin, silver and gold which have been excavated ever since. In later years, the mining of uranium ore became the main basis of the mining industry, as the other activities ceased. Porcelain manufacture and, in the Czech Republic, opencast peat mining give the landscape a bizarre effect, if you really wish to look out for it.
The first signs of igneous activity came early in the tour, when the bike route and forest paths were clearly made of a dark, fine-grained igneous rock. Having forgotten my hand-lens, nearer identification was not possible and the sample I collected seems to have found a way out of my rucksack, it has unfortunately disappeared completely.
The granite samples we collected in Saxony reminded me at first of Shap granite. Having now compared both, I have to inform the ‘Shap worshippers’ that the pink granites from the Erzgebirge are even more impressive, the orthoclase phenocrysts are certainly just as large as those in the Shap granite and they contain quartz phenocrysts of a similar size. Since the amount of biotite is relatively small and the amount of plagioclase relatively large, the whole colour is very much ‘pinker’ than that of the Shap equivalent.
Where does the volcano come into this story? As with many other things when I am touring with Christian and Sigi, Rolf included, it came about as the result of a misunderstanding. We had lunched well in Marienbad and were heading for Carlsbad for our second night in the Czech Republic. At times, usually the critical ones, the bike route was simply no longer signposted. We asked our way from some locals and with a good deal of interpretation as distinct from understanding, we set off in the direction indicated which seemed to agree with our map.
The path was fine at first, showing signs of igneous rock chippings, but it became steeper and steeper. Eventually we reached the top and were standing before a radio mast and transmitter and an information board with details of our volcano in Czech and German. We had cycled up an extinct volcano called Podhorni, 847m above sea level! Podhorni had ceased activity during the Proterozoic, but it is, or was, still a volcano. We decided to return to the point where we had left the bike route rather than attempt the continuation of the volcano path and soon discovered the error in our interpretation of the directions we were given. The unplanned ascent had cost us a significant amount of sweat and about an hour of hard cycling. The sweat we replaced later that evening, the lost time had to be ticked off as an example of ‘learning by doing’.
by Mike Molloy
If you like Mike and his bike, here is more of the like: A bike tour with an integrated field trip, Crossing the Danube, with dry feet and KTB Windischeschenbach.
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Last modified on Saturday, May 27, 2006 at 11:25
