Well this was my question (s) to the archaeologists last week and I did get a prompt reply but as everyone will see in the answer there is a problem of introducing a marker between the new and old fill of chalk - and they did'nt get back asap ;)

My Question....

Hi, I just wondered as there will be a different type of chalk from the original fill what is being done to ensure the new fill is easily distinguishable from this material?. Also there seems to have emerged from the backfill of Atkinson's time tyres, which seems to me somewhat reprehensible on the part of the people who were in charge of the monument at the time. I know this happened a long time ago but in view of the fact that Silbury has a now somewhat iconic status in the eyes of new 'druidic' groups can you justify allowing more offerings to be placed in the hill.
And, perhaps warming to my theme, as Avebury, like Stonehenge, has been given a sacred nature relating to its past prehistoric religious role, how do you set about defining the rules of an emerging religious impulse with that of prehistoric sites.....

Answer from Silbury Project ..........

"Thank-you for your comments.

With regard to the fill going into the tunnel, it will be very difficult and probably impossible to distinguish the new chalk fill from the Neolithic chalk deposits of the mound without introducing either a marker at the interface such as a membrane, or non-chalk materials such as re-cycled glass gravel into the fill - and there are arguments against either of these approaches. We will re-visit our thinking on this issue and get back to you on this asap.

It would of course be possible in any case to distinguish the new chalk fill from the non-chalk deposits eg turf and gravel that make up the mound of Silbury 1.
to my theme, as Avebury, like Stonehenge, has been given a sacred nature relating to its past prehistoric religious role, how do you set about defining the rules of an emerging religious impulse with that of prehistoric sites.....

With the tyres etc these had been placed in the backfill of the cut made to construct the tunnel entrance when the works were carried out with inadaquate supervision in 1969. There is no possibility of this sort of thing happening again.

We are not placing offerings inside the Hill, other than the 'time capsule' being designed by the children of Avebury school.

Best regards from the Silbury project team"