If there is purely electrical, "dry" fossilization, then searching Tunguska seems like a good way to test it. However, any fossils found there could easily be said to have been formed a very long time ago. I did a small search, nothing impressive, and I did turn this up--
In analyzing the chemistry of the various Greenland ice cores, study was restricted to a limited suite of ions; one of these was ammonium. Interpretation of the ammonium record concentrated on the issue of biomass burning, consistent with the idea that the main source of ammonium was likely to be forest fires.
However, the presence of a signifigant spike of ammonium at AD 539 +/- 1 in the GRIP ice core essentially coincident with the global tree ring downturn around AD 540 hinted at an extraterrestrial cause. This led to the recognition that a large concentration of ammonium at AD 1908.48 in the detailed GISP2 ice record appeared to be closely coincident with the 30th June 1908 Tunguska impact.
For anyone interested in this 'ammonium as a signature for impacts,' it can be pointed out that ammonium occurs at potentially significant dates such as...1491.15, not very far from the closest known approach by a comet on 21st Feb 1491."
http://tunguska.sai.msu.ru/content/abstract_all.pdf pg 80
Perhaps this goes to ancientd's AD 1500 Australian event?
Also, spherules and certain elemental anomalies are discussed on pgs 84 and 85. As Grey Cloud said, there is always a thread where these things have been hashed out already! But does a lack of petrified wood in Tunguska go a long way to disproving the idea that transmutation is responsible for some fossilization, or just that it has to be an even more powerful discharge?
“Oh for shame, how these mortals put the blame upon us gods, for they say evils come from us, when it is they rather who by their own recklessness win sorrow beyond what is given…”
~Homer