Racing furnaces from Brunn, Groß Siemz and Vietow
The racing furnaces in Brunn, Groß Siemz and Vietow in Mecklenburg-Western Pomerania , in which iron production could be proven at the beginning of smelting in northern Central Europe , were examined during excavations on the route of the A20 motorway . In Brunn , district of Mecklenburg Lake District , Groß Siemz , district of Northwest Mecklenburg and Vietow , district of Rostock , well-preserved remains of kilns from the centuries before the turn of the century were uncovered for the first time on the southern Baltic coast .
State of research
As far as we know today, iron was first smelted in the 2nd millennium BC. Won in Anatolia . According to written sources from the early 2nd millennium in the Near East , the value of iron here was around 40 times that of silver and more than 8 times that of gold . It was not until the turn of the 2nd to the 1st millennium BC that iron replaced bronze as a material for the manufacture of everyday objects in West Asia, Southeast Europe and North Africa and the areas entered the Iron Age . Another 500 years later, through the mediation of Greeks , Etruscans and Celts , the material was also able to displace bronze in northern Germany and Scandinavia . The availability of iron, which can be seen from urn burials, led research to the assessment that people had started to mine the local iron ore deposits - especially swamp and lawn iron ore. Racing fire places were easily identifiable and near ore deposits numerous places were known where the flowing slag typical of the process could be found in abundance. From archaeological research over the past 20 years we know that most of these places were created much later. These furnaces, located north of the Limes, were only the basis for iron supply during the 2nd to 5th centuries AD. Thus, the question of iron smelting during the pre-Roman Iron Age (500 BC to the turn of the century) was unanswered. When the investigations began in Brunn, Groß Siemz and Vietow, it was not expected that knowledge about the pre-Roman Iron Age would be obtained. Slag finds were known from all three places. Due to the small amount, however, they were seen as evidence of a forge of local importance.
Groß Siemz
In Groß Siemz, a settlement from the late pre-Roman Iron Age, five racing furnaces were found. The lower part of them was built into the wall of an approximately 60 cm deep pit, so that the reduction chamber was protected from three sides by the surrounding soil and the furnace was only accessible from the pit. In the best-preserved remains of the kiln, it was evident that the surrounding clay had become so badly bricked as a result of the smelting heat that the shape of the kiln with a diameter of around 30 cm was retained for more than 2000 years. Apparently the ovens had been used several times. The working pit was later enlarged until a stable earth wall was available for the construction of the new furnace. This procedure was repeated four times so that the working pit finally reached a size of approximately 2.5 × 7 m. The five racing fire furnaces from Groß Siemz were operated one after the other. This leads to the assumption that the iron smelting was operated for a longer period of time.
Vietow
About 115 km east of Groß Siemz, race furnaces were discovered near Vietow, which have similarities with the findings from Groß Siemz. Here the edge of a settlement was exposed, which dates from the 2nd century BC. Existed until the 1st century AD. A large number of kiln systems of different shapes could be detected, including five lime kilns . Of interest, however, was the discovery of 19 racing furnaces, 13 of which were concentrated in an area of almost 400 m². The area on the periphery of the settlement, which was to be interpreted as a work place, was on a gently rising slope that borders on a damp lowland. Six remains of stoves were built into the wall of pits. Although there are no brick remains of reduction chambers in Vietow, the parallels to Groß Siemz are unmistakable. All other racing furnaces, however, belonged to the type with a slag pit and were to be dated to the 1st or 2nd century AD. The change in smelting technology can thus be seen in Vietow.
Well
About 100 km south-east of Vietow, 11 racing furnaces were discovered near Brunn, which were also built into the walls of upstream pits. They were found on a plateau that was inhabited during the Stone Age and the Bronze Age. However, the ovens date from the last three centuries BC. BC and the first two centuries AD. The remains of Brunn were spread over the excavation area and not concentrated in one work place as in Vietow. However, the ovens occur in groups of a maximum of three. The high temperatures in the reduction chambers have resulted in the furnace walls being completely bricked up here too. Some of the racing furnaces still had slag in the combustion chamber, which shows that the furnaces were abandoned after a presumably unsuccessful attempt.
By the finds of Rennöfen can safely be assumed that in the eastern Holstein was recovered and in Mecklenburg-Western Pomerania in the centuries before Christ iron using relatively small Rennöfen as well as from Denmark to North West Germany and the Czech Republic under the term "halbeingetiefte Rennfeueröfen upstream working pit "are known. If these findings are taken into account, the functioning of the racing fire furnaces from Brunn, Groß Siemz and Vietow can be reconstructed as follows.
Procedure
First, a pit 60 to 80 cm deep was dug, which offered space for one or two people and a bellows. Clay lenses were chosen as the location, so that material for the construction of the furnace shaft was already obtained through the digging. A cylindrical opening about 30 cm in diameter and 60-80 cm deep was then machined into a pit wall. A shaft made of clay beads was placed on top of this combustion chamber. The success of the process depended on an adequate supply of oxygen. For this reason, an opening was made in the furnace face 10–15 cm above the bottom of the pit, into which the nozzle of a bellows was inserted. Before iron extraction began, the furnace had to be dried and pre-fired to avoid drying cracks. Then charging could begin with a mixture of charcoal and crushed ore. The capacity of the ovens must have been very modest. The yield was probably between 0.5 and 2 kg of flake iron per furnace. An existing research gap could be closed with the semi-recessed racing kilns discovered on the route of the A20.
See also
literature
- Hauke Jöns : At the beginning of iron smelting in the north - the racing fire furnaces from Groß Siemz, Vietow and Brunn. In: Uta Maria Meier (Red.): The A20 motorway - Northern Germany's longest excavation. Archaeological research on the route between Lübeck and Stettin (= archeology in Mecklenburg-Western Pomerania. 4). 2nd, unchanged edition. State Archaeological Museum and State Office for Land Monument Preservation Mecklenburg-Western Pomerania, Schwerin 2006, ISBN 3-935770-11-1 , pp. 97–100.