Mark Boslough, sometimes known as the Bos, claimed comets make up only one per cent of the population of earth crossing objects - and exist only for short periods of time (see http://cosmictusk.com/william-napier-to-mark-boslough/). This view echoes the mainstream consensus that comets are little more than dirty snowballs and disappear as quickly as they appear - and the Clube and Napier hypothesis has never been accepted. In fact, there is a fair bit of virulent objection to the hypothesis - not wanted. Opens too many cans of worms.
An interesting update on Claude Schaeffer can be found at https://lirias.kuleuven.be/bitstream/123456789/373607/1/SRL2013-Jusseret... and the authors have even consulted the Velikovsky Archives. It seems the ideas of Schaeffer may in part have been inspired by Arthur Evans, who excavated at Knossos and interpreted various destruction layers there to the effects of earthquakes.
George Howard has responded to the Mark Boslough press release - see posting a couple of days ago (Feb 2nd), and more or less enscapulates the issue by focussing on the fuss and bubbles when the PR people pushed like mad to grab peoples attention and assure them the YDB event debate was over. Kaput. Finished. Looks like it might be about to rise from the dead. Go to http://cosmictusk.com/holy-hagiography-over-the-top-press-joneses-mark-b...
C Warren Hunt, of http://eearthk.com fame, has a book that you can buy at www.polarpublishing.com, 'The Environment of Violence: readings of cataclysms cast in stone' Calgary, 1989, and in the section on drumlins he has some interesting ideas. He describes them as mounds of fluvial deposits, sand and gravel and stones, sometimes stratified and sorted, and in the consensus geological view, moulded by glacial ice.
Scientists from Royal Holloway College (part of London University) in association with Sandia National Laboratory in the US, and 13 other universities in N America and Europe are down as contributing to the conclusions, are all unanimous in saying a large impact or airbursting comet or asteroid is out of context in explaining the sudden dip in climate at the Younger Dryas boundary and even less in respect of explaining the disappearance of Clovis points and their replacement by the similar Folsom points (which appear derivative).
The AD775/6 event was a Thunderbolts feature a week or so ago - go to www.thunderbolts.info/wp/2013.01/16/caught-in-the-crossfire/ ... and Rens Van Der Sluijs mentions both the entries of 776 (A/Sax Chron) and 793 (Roger of Wendover). Rens is however critical of the mainstream handling of the issue as they studiously ignored the work of a number of scientists he lists, including Paul LaViolette (2011). The latter has produced a wealth of geophysical and archaeological evidence in support of big solar flares (or stellar flares) and the next step will be to get hold of his paper.
Lawrence sent me a link on this and it has been around several blogs and web sites as well as mainstream sources. The full article is available in pdf format at http://mnras.oxfordjournals.org/content/early/2013/01/08/mnras.sts378.fu... ... and here we have a new theory to account for the spike in 775/6, previously attributed to a very big solar flare and then discounted as it was too big by far. We then had a dilution of the size of the solar flare, jiggery pokery or otherwise.
An article in the Observatory 125 (2005) pages 319-122, 'Earth in the Cosmic Shooting Gallery' by DJ Asher, Mark Bailey, V Emil'yanenkar abd Bill Napier (see www.arm.ac.uk/preprints/455.pdf) claims the terrestrial impact rate appears to be substantially higher than current NEO population models imply but is consistent with a significant unsee asteroid and cometary contribution to the hazard. A bit of doomsaying but interesting in how it might have impinged on the past.
At http://phys.org/print275575752.html ... we learn that climate see saws are not just a feature of the most recent Ice Age but were happening in earlier epochs, even as long ago as two million years. This is where the lake sediments extracted from the area of the Olduvai Gorge in Tanzania have taken scientists - in search of the roots of human beings. For a period of roughly 200,000 years the climate oscillated between closed woodland and open savannah grassland - on five or six occasions. Each change is said to have occurred abruptly - in a geological sense of abruptness.
At http://phys.org/print274439306.html ... is a story from a paper peddling scary doomsaying to the CAGW heartbeat. In the Eemian interglacial, 125,000 years or so ago, it claims, pulse racing, the global temperatures increased and this had a remarkable effect - corals in equatorial oceans declined but corals in some temperate regions thrived. The scary bit is that this is interpreted as corals vacating the equatorial zone as a result of global warming and migrating to regions that may now be somewhat cool but were then agreeable to corals.