10th November 2005, 08:15 PM
Quote:quote:Can I ask a question? Regarding the seeding of the trench with glass balls, how is the subsoil re-compacted after the dig?
The 'subsoil' referred to in the paper about the green glass experiment actually means the natural gravel surface, i.e the surface into which negative archaeological features cut. Above this is ploughsoil. It can be confusing as sometimes archaeologists use the term 'subsoil' to instead refer to the B-horizon in some soil profiles (a geologist will probably tell you that we are incorrect to do that!).
Therefore the compaction of the 'subsoil' is not an issue. The green glass was placed in a 4cm deep cut in the subsoil to mimic a negative archaeological feature such as a pit. The 'artificial feature' was then re-covered by the ploughsoil that had previously been removed to expose the subsoil.
At the risk of repeating what is already written up in the paper,
the methodology of the green glass experiment was proposed by John Hinchcliffe of English Heritage (Acting Regional Director, who attends the site meetings every Friday) and was advised by Ian Panter the English Heritage science officer.
While it seems to me that the results of the experiment demonstrate quite clearly the damage caused by ploughing to archaeological features in the landscape around the henges (the astonishing and shocking results are limited to one ploughing episode - ploughing will continue to truncate the archaeology until it is gone. Not to mention the effects of the pan-busting that is often carried out in these fields), this is not the only evidence. The paper briefly refers in its introduction to several other pieces of evidence for the truncation of archaeological features in the vicinity of the henges.
Plough damage is - as is well known - a major threat to all archaeological features in farming landscapes. It is a problem to which EH don't seem to have a solution nationally, but in the specific case of Ladybridge farm it seems to rule out the preservation in situ of archaeological remains.
"So does your partner have a real job?" Asked of me by an interviewer for a supervisor post at a well known unit not that many years ago...