Mardelle
As Mardelle be both temporary, and year-round water-filled terrain depressions called. They have no inlet or outlet and are fed by rainwater. As a result, the water level may vary greatly depending on the season. Due to the constant change of the water level, a large number of plants and animals have adapted to life in mardelles. Whereby flora and fauna differ from mardelle to mardelle. Mardelles can be both shallow sinkholes , which were created naturally by subsidence of the ground, as well as artificial pits, which were dug from the Iron Age by removing material for building and pottery purposes.
Cultural and historical significance
In addition to taking building materials, mardels were often used as roasting flax , wood storage areas, cattle troughs, fish ponds or water reservoirs. In the Grünbachwald near Böckweiler in Saarland, for example, an approximately 30 m large mardelle was examined in the context of a biotope system during an excavation , which , due to its size, cannot have been created by natural leaching in the lower shell limestone there . During the excavation, a jug with a handle and other Roman shards were found under a layer of peat up to 40 cm thick . A pottery furnace from Roman times was found 130 m away from the Mardelle and two Roman settlements in the vicinity. During research into his dissertation on mardelles, David Étienne from the University of Nancy also found indications of anthropogenic origin in some mardella and was able to determine their age to about 2,000 years with the help of pollen analyzes. In the more recent past, mardels, which are also popularly known as the puddle, have often been considered scary and nasty places. There are also legends about many of these pools. In the 16th and 17th centuries, there were even witch trials in connection with mardelles in French Lorraine.
Mardels that were in open areas were often backfilled in order to make them usable for agriculture. For these reasons, mardelles are rarely found in open areas. The situation is different with mardelles that lie in forests, as only a few artificial backfills have been carried out there. These can be found here even more frequently.
Origin and dating
The type of origin (whether natural or by humans) and the dating of the age of a Mardelle can only be finally clarified through an extensive excavation or the removal of drill cores. Mardelles always form sediment traps with excellent conservation conditions for plant and wood residues or human settlement remains. Such studies make it possible to make far-reaching statements about environmental history, such as B. on vegetation, climate and settlement history. Because of their high information potential for both archeology and environmental history, mardelles should definitely be recorded and protected as archaeological monuments. The dredging of largely silted up Mardellen as part of the wet habitat protection is to be rejected for the reasons mentioned.
Today, science assumes two types of origin for naturally occurring mardelles. These are described in the pingo theory and the sinkhole theory.
The pingo theory (the mardelle as a pingo ruin)
Basically, pingos arise from the different levels of freezing readiness of different soil layers. A distinction is made between pingos of the Mackenzie type (closed type) and the E-Greenland type (open type). If the ice core melts, the pingo collapses and forms a depression in the ground, the so-called pingo ruin or mardelle. Characteristic of mardelles that are created in this way is the earth wall that surrounds them. This is caused by soil that is deposited on the edges when the pingo sinks. In Europe, pingo ruins are found predominantly in the north-western part of Central Europe. Most of the world's pingo ruins are in Holland, some areas of Alaska, and north-west Canada (Mackenzie Delta).
- Mackenzie type (closed type)
These pingos arise when segregation ice forms under a silted up thermokarst lake or pore water that is injected while the permafrost is advancing. In both cases, the resulting ice core pushes the ground upwards. If the ice core thaws, the pingo collapses and forms a depression in the ground.
- E-Greenland type (open type)
These pingos arise when injection ice forms in the ground. This ice is formed by rising groundwater from the non-frozen layers under artesian pressure. Here, too, the pingo collapses after the ice core has melted and forms a depression in the ground.
The sinkhole theory
The theory is based on gypsum lenses in the ground. These plaster bubbles are gradually dissolved by penetrating water (rainwater). This dissolution process creates a cavity under the surface, which then collapses due to the pressure of the soil above, creating a depression.
Bettina Barth, for example, describes mardelles in Gipskeuper in Lorraine, south of Saargemünd, as the products of leaching of gypsum lenses, which led to a lowering of the soil above, while at the same time sealing the mardelle sole. It differentiates mardelles according to their morphology and their location. Mardell can always be found in the hilltops or upper slope area, never on the lower slope or valley floor. When excavating mardelles on the occasion of the alignment of the TGV railway line Paris-Strasbourg in the Keuper area of Lorraine, Étienne did not find any gypsum lenses and only allows the sinkhole theory to apply to areas in which limestone is shallow and the formation of sinkholes for the subsidence of marl or clay layers above leads.
literature
- W. Reinhard: The mardelle, a neglected ground monument . In: Association of regional archaeologists in the Federal Republic of Germany (Hrsg.): Archeology in Germany . 3/1996 July – September. Konrad Theiss Verlag GmbH & Co., 1996, ISSN 0176-8522 , News from regional archeology - Saarland, p. 51 , col. 2-3 .
- Bettina Barth (1996): Mardellen in Gipskeuper, Lorraine , using the example of Foret de Farschviller , pp. 7–60, 18 illus., Treatises Dellatinia 22, Saarbrücken
Individual evidence
- ↑ a b c d Dieter Dorda - Mardellen in southern Bliesgau (PDF) - Series of publications "From nature and landscape in Saarland", pages 229 to 236, Abh. 22/1996, self-published by the DELATTINA working group at Saarbrücken University, ISSN 0948-6526 - On: www.delattinia.de - accessed on September 25, 2018
- ↑ Löhr, Hartwig: Maars, fairy tales, mardelles, little-noticed ground monuments? In: Kurtrierisches Jahrbuch 25 (1985). Pp. 3-9.
- ↑ European Academy Otzenhausen - Archäologentage Otzenhausen Volume 3 (PDF) - Page 268 - On: www.eao-otzenhausen.de - accessed on September 25, 2018
- ↑ a b David Etienne - Les mardelles intra-forestières de Lorraine - Origines, archives paléo-environnementales, évolutions dynamiques et gestion conservatoire (French) (PDF) - At: docnum.univ-lorraine.fr - accessed on 25 September 2018
- ↑ O. Schäfer-Guignier: Vegetation studies on small bodies of water in the Palatinate Forest and the Westrich plateau , Mitt !. Pollichia 74, 175-204, 1987, Bad Dürkheim
- ↑ Löhr, Hartwig: "Mardellen" and similar sediment traps: A specific wet soil situation in the low mountain range. In: Archäologische Informations 9 (1986). Pp. 104-109.
- ↑ Pingo ruins and permafrost . pingos-neu.kge-suss.de. Archived from the original on September 29, 2018. Retrieved January 12, 2020.
- ↑ www.spektrum.de Lexicon of Geosciences - On: www.spektrum.de - accessed on September 25, 2018
- ↑ Klaus Eberhard Bleich: On the origin of pingos in the Mackenzie Delta, NWT (PDF) - at: epic.awi.de - accessed on September 28, 2018
- ↑ van Mourik, JM; Braekmans, D .: Mardellen (PDF) (Dutch) University of Amsterdam - Institute for Biodiversity and Ecosystem Dynamics - At: pure.uva.nl - accessed on September 28, 2018
- ↑ Bettina Barth - Mardellen in Gipskeuper in Lorraine (PDF) - pages 7 to 60, series “From nature and landscape in Saarland”, Abh. 22/1996, self-published by the DELATTINA University of Saarbrücken, ISSN 0948-6526 - on: www. delattinia.de - Retrieved September 25, 2018