It is no coincidence that the first Dutch geopark is located in Drenthe. After all, that province is rich in archaeological and geological phenomena, such as the dolmens and a landscape formed by the last ice ages. The initiators want to tell 'the story of De Hondsrug' more clearly. Not only with an emphasis on the top locations, but especially about the relationship between them within the ice age landscape.
De Hondsrug Geopark, that received its official status this week is a first for the Netherlands. While in the rest of Europe about fifty geologically interesting areas already bear the Geopark 'quality mark', it was now Drenthe's turn. The area includes the municipalities of Coevorden, Emmen, Aa and Hunze, Tynaarlo and Borger-Odoorn. “It is a landscape that was formed during the ice ages and has been strongly influenced by human habitation since prehistoric times,” says Harrie Wolters of Geopark de Hondsrug. Incidentally, the Dutch geopark has been running at full speed for some time, because that is the requirement to be recognized by the network organization, the European Geopark Network (EGN).
Status
“That's why not much changes for us with the new status,” says Wolters. “We will be organizing more lectures and courses, also aimed at education. Because we are now an official geopark, we expect more support among organizations and the 200,000 residents of this area. We want to spread the story about the Hondsrug to a wider audience." But, what is that story actually?
Car tracks and sand ridges
“No fewer than 47 of the 53 Dutch hunebeds are located in the Hondsrug region,” says Wolters with pride. "There are many geological phenomena, such as sand ridges and pingo ruins. But what is especially important is the coherence between all present geological and archaeological phenomena, also in relation to the current nature and cultural history of the area.”
This coherence can be found, among other things, in the old road pattern on the old sand ridges. This pattern has determined the current location of and connecting routes between the towns and villages in this area. For example, the route from Coevorden to the city of Groningen runs over prehistoric cart tracks on the sand ridges. The location of the villages and towns in this area is directly related to the presence of the high sand ridges. Wolters:“These old roads go back to the time of the hunebed builders”.
Ice tongue in 'dead' ice sheet
“The pattern of the sand ridges – there are four, of which the Hondsrug and the Rolderug are the most prominent – are geologically unique worldwide,” said Wolters. “This stripe pattern – in geological jargon megaflutes – you only see here and in the north of Canada worldwide.” The physical geographer Enno Bregman, who is affiliated with the Geopark, writes that the Hondsrug IJsstroom and the Canadian Dubawnt Ice Stream to date are the only known 'terrestrial ice flows' on Earth to have arisen as a result of a glacial lake breach.
The linear sand ridges in the Hondsrug region were created during the Saalian, the second-to-last ice age, by the erosive effect of a fast-flowing ice tongue that was wedged in a motionless ('dead') ice plain. But geologists have been arguing about the exact origin of the linear 'ridges' in Drenthe for a century and the last word has not yet been said.
History book of the ice ages
The succession of ice ages can be clearly seen in Geopark de Hondsrug in the Steilrand Donderen, a special remnant of a sand quarry that shows the deposits of the last hundreds of thousands of years in detail. As many as (probably) three ice ages succeed each other in this outcrop. The steep ridge in the municipality of Tynaarlo, just on the edge of the geopark, was named the second Geological Monument of Drenthe a year ago.
In the steep edge, for example, a thick layer of Peel sand can be seen at the base, which extends even meters deeper. It is white, fine sand, deposited by meltwater during a relatively warm period within an ice age, probably from the Elsterian. The dating of the oldest deposits visible here, however, has not yet been established with certainty. It is also possible that the Peelo sand was deposited during the earliest Saalian. The same sand also comes to the surface in the drifting sands of the Balloërveld. In the Hondsrug region, everything is connected with everything.
Water tank
The geology in the Drenthe geopark is a source of inspiration for many current themes, such as climate change (the climate also changed relatively quickly during the ice ages). Water is also a theme that ties in with the new geopark. “In the Hunzedal – the primordial stream of the Hunze – the groundwater, which comes up there as seepage water and is extracted as drinking water, is hundreds to thousands of years old,” says Wolters, “and is therefore very clean. The Hondsrug region is a huge water reservoir. This is the most northern area in our country where the groundwater is not affected by the salty seawater.”
Historical relief
The Hondsrug is (maximum) about seventy kilometers long and is higher in the southeast, rising from 5 meters above NAP in Groningen to 20 meters above NAP in Emmen. It is a small difference in height, but for the Netherlands quite significant. The Hunze Valley, which was created at the end of the Saalian by the force of flowing meltwater, was at that time – around 150,000 years ago – even 40 meters deeper than the surrounding landscape. This large relief was partly destroyed in the ice age that followed, the Weichselien. Then cover sands partially fill the valley again.
No “geology with a fence”
Special geological areas worldwide receive timeless protection if they are placed on the UNESCO World Heritage List. Although UNESCO is also involved in the development of geoparks in the background, the geopark concept is slightly different. A geopark is not a “fenced-off geology”, according to Wolters. “Because geological areas are often very large, people also live there, and they also need an income.” The geopark approach is therefore focused on sustainable development of the area:stimulating economic activities around the theme of geology, activities that are mainly aimed at tourism.
Local population
“Unesco does not yet have a special 'category' for geoparks, but that could be developed in the future,” said Wolters. “You should see a geopark as a bottom-up concept, with a lot of involvement from the local population. In contrast, the main purpose of a geological site that is included in the World Heritage List is protection, with as little economic activity as possible. Geology is not yet a high priority for UNESCO.”
For example, Mount Fuji is not a World Heritage Site because of the geological, but because of the cultural significance of this volcano. Wolters:“The ideas about this at UNESCO are changing. Meetings will be held again in November this year to discuss the status of geology within the World Heritage and the place of geoparks therein.”