Clay Materials at Alvastra Pile Dwelling
Objects made of clay vary from raw, untreated clay to deliberate mixtures of several mineralogical and/or organic compounds kneaded into the plastic raw material.
The difference in treatment of the clay within the current project defines the difference between ceramics and clay artefacts. The following text discusses untempered clay artefacts, i.e daub, burned clay and unburned clay.
This text is introduced by previous research concerning the daub and burned clay. An account of the recording strategy is available here and the results thereof can be read below under the heading Mats P. Malmer’s excavations.
Otto Frödin’s investigations
In the material from Frödin’s excavations both daub and burned clay were identified and recorded. According to Browall (2011:292) there are no clear differences between, or definitions of daub or burned clay in the museum catalogue. Browall suggests that since both categories contain larger pieces (c. 8cm) as well as pieces with imprints of plants and other materials, the difference between the two materials must be that the objects defined as daub were at some point considered to be a sealing agent in the wooden constructions and the hearths. Burned clay, on the other hand, must have been defined as clay material of more uncertain origin (Browall 2011:292). Thus, it is unknown how burned clay and daub were previously defined.
Mats P. Malmer’s excavations
The current project
The recording strategy is founded on previous research concerning the pile dwelling, (Browall 2011), set parameters in the former database of the museum as well as an initial ocular assessment of the entire material.
The recording of clay materials from Malmer’s excavations resulted in three different categories: daub, burned clay and unburned clay where the latter category was added as a result of assessing all clay artefacts at the site, that is to say: pottery, dissolved pottery and clay coils as well. Different stages of clay preparation have at one side of the spectrum led to daub and on the other side to pottery; in between burned clay, dissolved pottery and clay coils are found, as well as unburned clay. Unburned clay is currently difficult to comprehend, however, still being the result of a clay processing activity. The technical qualities formed the definitions of the objects (see Recording Clay Materials). The methodology of determining the artefacts categories in the current database has been ocular assessment of the clay material itself; if it appears to have been burned or if it is dried as daub would be, a difference that on many occasions shows as differences in stability.
Analysing the clay material
There are 202 records/828 objects recorded within the current project weighing 6,5kg (6522,2g). The largest amount of clay material is found in the Eastern trench (123 records/594 objects), followed by the Western/Trial trench (53 records/188 objects), the Middle trench (25 records/45 objects) and lastly the New Trial trench (1 record/1 object; see table 1). It is worth mentioning that the objects of burned clay weigh 5818,2g i.e. 89,2% of the total weight of the entire clay material assemblage, consist of a few records containing a large amount of burned clay. The large records represent the bulk of the burned clay material recorded from Western trench as well as all trenches within the current project. The clay material is analysed and fully presented in table 1, the number of records and objects are presented together in order to facilitate calculations of the material categories. Detailed information about the different categories is discussed below.
Daub
There are 109 records/537 objects of daub recorded within the current project (see table 2). The entire assemblage weighs 558,13g. A few objects have imprints (9 records/14 objects), where less than half of them (3 records/4 objects) are determined as imprints from plants.
The daub can best be described as amorphous lumps, yet a small number of objects have distinguishable form (3 records/6 objects); one of these objects (1 record/1 object) is rounded. Soot and organic residue occur (3 records/4 objects and 1 record/1 object respectively).
Daub in the different trenches
The majority of the daub objects are found in the Eastern trench (68 records/355 objects) followed by the Western/Trial trench (29 records/156 objects) and lastly the Middle trench (12 records/26 objects; see table 1).
Interestingly, all objects determined as having plant imprints (3 records/4 objects) are found within the Western trench and all objects determined as having other imprints (6 records/10 objects) were found in the Eastern trench. However, there are few objects in total that are determined as having imprints (9 records/ 14 objects), weighing 19g in total. The objects are small and determining the imprints as either plants or other imprints is difficult.
Burned clay
The category burned clay contains 51 records/108 objects that weigh 5818,2g (5,8kg). However, only a few records (6 records) weigh 5703,6g, that is 98% of the total weight of the material category. This can be compared to 114,6g which is the total weight of the assemblage without these records (45 records/108 objects) as well as the mean weight of each object 1,1g.
4 records/5 objects with imprint are worth mentioning. Two of these objects are decorated and one object displays imprint from plants (possibly a seed). Amongst the burned clay objects 1 record/5 objects are determined as fragments of a clay coil and another 2 records/2 objects have somewhat deliberate form in comparison to the rest of the material, and 4 records/9 objects are rounded. No burned clay fragments display soot, yet 2 records/3 objects have attached organic residue.
Burned clay in the different trenches
Most burned clay fragments are found in the Eastern trench: 25 records/85 objects. There are 13 records/18 objects recorded from the Western/Investigation trench and 7 records/9 objects from the Middle trench. 1 record/1 object objects has been recorded from the New Investigation trench.
It is of note that all of the above-mentioned large records that contain 98% of the total material in weight are found in the Western trench. Most of the rounded burned clay objects are found in the Eastern trench.
Unburned clay
This category contains 42 records/183 objects. However, not all records contain material that could be counted due to instability and small fractions – 4 records contain uncounted dried clay. Yet, all records are weighed resulting in 145,8g for the entire unburned clay material. As mentioned above, the category is a result of the many unstable and probable unburned clay fragments found amongst the daub and burned clay objects; the unburned clay is much more unstable than daub that is unburned, yet dried. No objects display soot or any types of imprints, but 1 record/1 object could be partially coated in organic residue.
Unburned clay in the different trenches
Most unburned clay fragments are recorded from the Eastern trench, 30 records/154 objects, where 3 records could not be counted. In the Western- /Investigation trench 6 records/19 objects were recorded, 1 record could not be counted. Lastly, 6 records/10 objects have been recorded from the Middle trench.
Text: Nathalie Hinders
The following reference cited here has no web link:
Browall, H., 2011. Alvastra pålbyggnad. 1909-1930 års utgrävningar. Kungl. Vitterhets Historie och Antikvitets Akademien. Handlingar. Antikvariska serien 48. Stockholm.