Hello Bill
The answer to some of your observations about what happened glacially in the NWT being perhaps similar to what happened(s) in Manitoba, may be very valid, with the exception that there is no permafrost in Winnipeg to my knowledge, as there is here.
The bottom line is nobody has the answers. New theories and research are routinely proposed and presented both for glaciation and diamond emplacement and exploration geologists try applying those theories and seeing if their exploration success improves. Case in point is Ashton's recent success in Alberta as a result of Lithoprobe in formation published last year.
If you check some of the GSC sites you will find quite a bit of information both here and from some countries with historic activity in this field.
Try using the following search engines which are increadibly fast and broad:
http//www.metacrawler.com/
http//www.altavista.digital.com/
Search under terms like diamond, volcano, kimberlite, geology, ice age, plate tectonics, continental drift, craton, archon, peridotitic, eclogitic, kaminsky, rumbouts, jennings, gurney, lithoprobe, etc, etc.
You will also find very relevant information on a number of company sites such as southernera, canamera, diamet, cypango, ashton, etc.
I should repeat that much of the best information I have been able to find has been from books, published articles, papers, and conversations with experts in the fields of diamond emplacement, exploration, glaciation, and geophysics. Some of the most thorough and readable were from the Gems & Minerals quarterly.
I have also bee quite fortunate living here and having had access to a great deal of archived research and having attended and followed up on papers presented at the annual NWT Geoscience Forum.
One last point Bill, whether the boulders are angular or not probably has little to do with proximity to source. The fact that the boulders exist in abundence is far more relevant and indicative of close source proximity. These were more than likely scoured by glaciers and/or heaved by permafrost action and moved mechanically by ice and/or water. However, be assurred that any boulders spit up by an erruption 60 million years ago no longer exist unless deeply burried. If they had been burried they would have been generally preserved in their partially reabsorbed rounded form and not angular. Any surface iregularities more than likely would have been caused be severed climatic and mechanical forces.
The likelyhood of burried boulders from the original erruptions is probably near zero as I have suggested before, this area is deeply erroded. The original volcano probably errupted through several miles of archean aged mud stone or graywacke which has long since been erroded exposing the current granite bedrock and what I have suggested is probably a root zone dyke system. As I have also suggested, I believe on another site, a local expert in the field expressed a similar opinion to me several weeks ago.
There could be pipes but I am afraid the likelyhood is less likely than elsewhere on the craton.
Good luck.
Regards |
