Following up on recent posts, here is an observation which the list might find interesting: one of the pillars of the entrance of St Marc's cathedral in Venice contains a beautiful fault, oriented favourably for slip in the present day stress field of the building. I enclose some photos I took on a recent trip.
So here is a nice example of faults in carbonate which are completely re-sealed and become as strong as the wall rock.
Maybe our Italian colleagues can correct me if I am wrong, but I have seen similar structures in the in the Laaser series marbles, and interpreted them to be early (pre-Alpine) and having undergone Alpine Metamorphism with very little deformation so that the fault geometry is preserved. Maybe someone know of a paper on this?
It is interesting to consider how much the stone-masters who built the cathedral understood about faults and fault seals. Perhaps one could even develop the idea (along the lines of popular literature) that they were trying to send us a message and the the solution to the fault seal problems we are trying to solve are hidden in Vatican Archives?
kind regards,
Janos Urai
|