http://atlas-conferences.com/c/a/j/i/26.htm claims that cosmic activity has been detected in raised bogs in NW Europe and in Siberia (at Tunguska). These traces appear to correspond to episodes of rapid climate change in the Middle and Late Holocene. Lars Franzen of the Earth Sciences Centre at Goteburg in Sweden says raised bogs are an archive of atmospheric deposition in peat over the last 10,000 years (the end of the Younger Dryas Event). Generally, bogs and swamps are places that lack human interference – which is important as only very small amounts of mineral particles are being looked for as plants also form biogenic silicia or phytoliths. The cosmic component, found under the microscope, includes micro-meteorites, micro-tektites and peat ash (evidence of fire), from mainly Swedish bogs – but also four Irish and three Norwegian mires have also been sampled – as well as surface peat taken from near Tunguska. A high cosmic flux occurred at (roughly) 7000, 3000, 2300, 1700 and 1000BC. The latter figure is intriguing as it doesn’t conform with the low growth tree ring signature of 1159-41BC (revisionists take note). There were also cosmic signatures at 500BC, 550AD, 850AD, and 1300AD (which appears to confirm some of Mike Baillie’s ideas in New Light on the Black Death – reviewed in SIS ) as well as anomalies at the peak of the Little Ice Age (presumably the 1600s).
http://news.nationalgeographic.com/news/2010/02/100203-asteroid-collision-earthth-global-cooling/ – (if web page not accessible go to national geographic website as per and click home and then click science on the top banner) – has a story concerning Dallas Abbot who suggests pieces of an asteroid or comet broke apart over the earth and crashed into the ocean near Australia – in around 550AD. There are two craters on the seabed and Aboriginal rock art in the region appears to record the event – or something very much like it. There are numerous example of fiery stars falling from the sky and striking the earth in Aboriginal Dreamings, it is claimed, all over Australia and not just near the Gulf of Carpentaria. Emilio Spedicato, of Bergamo University in Italy, a member of SIS and a poster presenter at the 1997 Conference in Cambridge, has dated these craters somewhat differently – so an actual connection is not assured (but the paper is yet to be published – apparently this story is a press release of some kind). Criticism at the moment has coalesced around the idea there are just too many hopeful impact events – and these do not agree with the numbers expected by the calculations of astronomers (statistical analysis of random events). However, www.sciencedaily.com on December 15th 2009 had a story that comet impacts might be much more frequent that science currently allows as evidence of them is hard to find. There is a potential signature in ice cores generally unrecognised, it is claimed, that of nitrate and ammonia. High nitrate levels have previously been linked to cosmic events but atmospheric ammonia episodes as indicators have not been used (but see Mike Baillie in New Light on the Black Death). The Tunguska episode in 1908 and the YD boundary event at 12,900 years ago were studied and in both instances evidence was found whereby a nitrogen fixation reaction produced ammonia.
Lars Franzen and Thomas Larsson also had a presentation at the 1997 SIS Cambridge Conference, the abstract of which can be viewed on this web site. Geomorphological signatures, and playa and alluvial fan deposits seem to indicate there was a severe flooding event in central Tunisia at 1000BC. Precipitation must have exceeded 10,000mm in a very short period. There was also evidence of ground frost in the initial phase of the event (which might coincide with a low growth tree ring event).
Another poster presentation from the same SIS Conference (see abstract on this web site) makes the point that there was unstable behaviour of lower river valleys influenced by erratic global climate as well as the transition of rivers into their present meandering form and their deltas in the late 4th millennium (3200BC). Richard Meehan, the presenter, according to Google, is not currently researching this subject, although the SIS article is picked up on page 2 or 3 of Richard Meehan, Google. This particular point in time – has implications regarding previous as well as later projected cosmic events (such as 536-45AD). The presentation had the title, Testimony of the Oaks; Evidence of Climatic and Geomorphic Changes in Lower River Valleys at 3200BC. His work, in effect, overlaps with the research of Paul Dunbavin (two of his books are available from the SIS Book Service) but we might expect hydrological changes to be a feature of catastrophes after 3200.