Sterile Soil......

As the readers of this Blog know, one goal of archaeologists is to reach "Sterile Soil", namely virgin soil unaltered by man. By achieving this, archaeologists may discuss the earliest phase of occupation. In the past the PFP has reached sterile soil, but in most cases we did not reach the bottom of the trench, so to speak. Among the goals of the 2011 was to reach sterile soil, like it or not, and we did.

Trench 22N was the most satisfying. We began excavating this trench in 2010, but halted at a depth of 0.9 m when we unearthed a "late" hearth (see preliminary results of 2011 season at http://www.porolissum.org/). In 2011 we "sectioned" the hearth - literally slicing it in half - in order to verify what lay below. We found a series of very deep Roman fills with an abundance of archaeological materials. At a certain point, ca. 2.5 m in depth the materials ceased, but we encountered a thick and dense layer of charcoal-filled clay - we had reached the earliest level of the site, the timber and earth phase which dates to the time of Trajan (we even found an coin of Trajan). Since the clay was so deep and the surface of the trench so broad, we sectioned part of the trench in order to see the depth of the timber/earth layer. At a depth of ca. 3.0 m we reached virgin soil; thus we obtained the full sequence of activity in the trench.

Trench 11 was also interesting, but the students felt more like miners than archaeologists. Trench 11 holds a complex sequence of architectural features beginning with a timber/earth phase at the lowest level. Sequentially, this is followed by a massive building campaign during the reign of emperor Antoninus Pius, when a public building of unknown function was constructed. This structure was renovated on several occasions and included no fewer than 5-6 superimposed floors. The last significant building phase was in the Severan period. The layers simply continued downward, but we were determined. Finally, during the last days of the project at a depth of more than 4.0 m. we reached a layer of clay with no human-generated debris.

Trench 33, at the highest point of the site, was and is perplexing. The magnetometry results from the 1990s indicated an architectural feature. Being the highest point of the site, we fantasized about a monumental gate or a temple. In the end and after excavating about 20 cm of earth, we encountered traces of walls. After just about 10 more cm we had reached the bottom of the walls (which had been robbed in recent times by local farmers from Moigrad and Jac). There was a large building which measured at least 10 x 10 m., but it was not consistent with a public building. In fact, we speculate that this was either a house or an industrial/commercial complex (a kind of kiln was found in association with the architecture). The oddity was that seemingly sterile soil was encountered at an average of 30 cm below the modern ground level. The Romans had dug into the clay for the foundation of the building, but we did not encounter any cultural material in the clay. Just to verify, some of the students were asked to excavate to a depth of nearly 2.0 m., but they only excavated clay. A nearby trench (4) from PFP 2006 gave similar results. We wonder if this is indeed the natural clay or if it is virgin clay that had been artificially piled into a defensive mound, surrounding the original wooden feature of the Trajanic period. We will have to investigate this in future years.