domingo, 1 de diciembre de 2013

2000 year old iron furnaces found in Poland

Excavations at Kanie (Mazovia Voivodeship) in Poland have uncovered the second largest centre of iron production in this area, dating back 2000 years.
Finds that were of greatest interest to the archaeologists were a timber well of unusual design, a number of bloomery furnaces for smelting iron and according to the researchers, the site fits well into the pattern of other known ironworks settlements located in the Błonie Plains.
Przeworsk culture
The site also increases further understanding of mass production of iron in the territories inhabited by the Przeworsk culture which is part of a Polish Iron Age archaeological complex that dates from the 2nd century BCE to the 5th century CE.
Robert Wereda of the Museum of Ancient Mazovia Metallurgy in Pruszków explained “We found 22 furnaces filled to varying degrees with slag and residue and intense black burn, and two half-dugouts, which contained numerous pottery sherds”
The Przeworsk culture is seen as an amalgam of a series of localized cultures and is often associated with the Vandals who are thought to have migrated out of Scandinavia into the Baltic coast of Poland in the 2nd century BCE.  These Iron Age tribes had peripheral connections with the Roman Empire.
Unusual timber construction
However, it was the well that was of particular note to the researchers due to its design, which they believe may be a unique discovery in Poland.
“What distinguishes the well we have discovered from other such objects dating from the Roman period, is the use of vertical-post log design, which is characteristic of residential buildings, in the construction of timbering” – said Wereda.
The archaeologist explained that the walls of rectangular wooden wells were usually built using what is called ‘carcass construction‘, consisting of horizontal wooden beams slotted together at the corners.
Due to the preservation on this site the archaeologists were able to examine a different technique where the hand-split oak planks were inserted into vertical grooves in four pillars embedded in the soil. The preserved height of timbering was about 1.30 m while the lower section of the well was lined with stones to a final depth of approximately 3.40 m.   The wooden structural components were very carefully jointed and each piece was caulked with clay and birch bark, which improved the waterproof nature of the upper structure.
Several post holes surrounding the well, indicated the existence of a small surface building that provided roofing for the well. The archaeologists also discovered the traces of what was probably a lever crane used to draw the bucket from inside the well.
Various fragments of ceramics were found inside the well but on the whole it was relatively clear of refuse. Most communities of the Przeworsk culture used old wells as rubbish pits and filled them with broken items and other waste, however in the case of the well in Kanie, it appears that the well had been in use until the end of the functioning of the settlement, when it was deliberately backfilled in a single event.
Currently, timber from the oak structure is being kept in the Museum of Ancient Mazovia Metallurgy in Pruszków in preparation for conservation and dendrochronological analyses.
An Iron Culture
The site also contained 22 structures used in the smelting of iron. The furnace type was called a bloomery and consisted of two parts: upper – a pit or chimney, approximately 2 m high with an opening at the base where slag was collected.
Experiments have shown that  each bloomery would take 200 kilogrammes of  iron ore, which could be brought up to a temperature of 1200° C using charcoal.
Settlements such as this one were producing industrial quantities of iron for a variety of purposes and as such this  specialised village would contain all the stages of metallurgic processes with clay and iron ore sources close by. Blacksmith workshops, bloomery furnaces and wells are normally all found together at these workshop settlements.
Currently in the Mazovia region archaeologists have located 238 within a relatively small area of only 300 square kilometres.
Excavations prior to new water supply system
The archaeological work preceded the construction of the water supply system. Excavations were headed by Dorota Słowińska from the Stefan Woyda Museum of Ancient Mazovia Metallurgy in Pruszków.

Source: Past Horizons:

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