Smelter clay
Daub or Brandlehm , as rotlehm or Staklehm called, is an archaeological find material . It consists of clay that has hardened due to a fire and is often reddish in color.
Use of clay
The material clay has played an important role in house building since mankind began to settle down . Finds of metallurgical clay can result from very different uses of clay. The material consisted, for example, of clay bricks , furnace walls, fixed furniture or plastering of buildings. The Roman historian Tacitus described the clay plaster of Germanic houses in his writing Germania (Chapter 16) in the 1st century AD as follows:
- "They use raw wood ... They coat some places more carefully with earth that is so pure and shiny that it looks like painting and color drawing."
Conservation conditions
In Central Europe with its humid climate, unfired clay artifacts that have been brought into the ground melt and are only preserved as a stratum . Clay only retains its shape when it is burned. Low temperatures of 350 to 400 degrees Celsius are sufficient for this, while at least 800 degrees Celsius are required for ceramic production . The effect of heat leads to a hardening and water resistance of the material, which is also called bricking. Heating can be done in different ways. Clay ovens and stoves bricks simply by using them. The clay plastering of the wattle-and- daub walls of prehistoric post houses can be preserved as hut clay if the houses are burned down. The fire hardens the clay and makes it durable.
The way it remains after a fire is decisive for the preservation of smelter earth. The best preservation is given by covering it with soil soon. If the residues remain on the surface, they will quickly pass due to the weather.
archeology
In the settlement context, smelting clay is a common type of archaeological finds and is important for settlement archeology . Much of the foundry clay found today comes from prehistoric post houses, as they often burned down.
In archaeological excavations, smelting clay comes to light mostly in the form of small to fist-sized fragments of burnt or half-burnt clay. The former context of use of the material can be determined in different ways. If the material is well preserved, this is possible using the shape. The function can also be determined from the surface of the pieces. It sometimes shows material impressions, such as wickerwork or smooth traces of hands. The material composition of the clay and thus its earlier use can also be determined. In house construction employed clay has a generally temper on from vegetable or mineral materials such as chaff, straw, sand and clay. The admixtures reduce the clay mass and prevent cracking during the drying process.
See also
literature
- Janine Fries-Knoblach: Hüttenlohm as a source for the construction and design of Iron Age buildings. In: Peter Trebsche, Christiana Eggl, Ines Balzer: Architecture. Interpretation and reconstruction. Contributions to the meeting of the Iron Age working group during the 6th German Archeology Congress in Mannheim 2008 . Beier & Beran, Langenweißbach 2009, ISBN 978-3-941171-19-0 , pp. 31-53.
- Franziska Knoll, Mechthild Klamm, Frank Lehmkuhl: Clay as a building material - tried and tested for thousands of years: archaeological, historical and recent evidence of earth building: a guideline for dealing with "red or hut clay" in archaeological findings. (= Small booklets on archeology in Saxony-Anhalt. 12). Halle (Saale) 2015, ISBN 978-3-944507-18-7 .
Web links
- Photo and description of smelting clay as an exhibit in the Lippisches Landesmuseum
- Description of fire clay found in Monjukli Depe in southern Turkmenistan