Monday, June 21, 2010

The mystery of the glacial sandwich

Red = Silt layer, Blue = Glacial debris? 
Bluffs on the east side of the Tranquille River

Now for something completely different I offer up the following mystery. On the hills to the east of the Tranquille river is an exposed piece of real estate. Like some giant turkey club sandwich, minus the turkey and all the good stuff of course, is a mystery, wrapped in an enigma, shrouded in a riddle (or something like that).

The gravel bars could have been deposited by either a river, or more likely a glacier and the silt could have been deposited when the lake covered the land. That would explain the bottom layers of the sandwich, but why the next two layers? My understanding was that there was an ice age that covered this area a couple of years ago, but this sandwich seems to suggests that the ice age was duplicated at least once and possible twice.

Or is there some other explanation for the gravel deposits: was it giant pocket gophers, or perhaps aliens experimenting with terraforming? I for one am flummoxed. And I am sure there are not many of you that can truthfully say that you have had occasion to say the word flummoxed, so "Ha" on that one as well. Unless, of course you can come up with the real reason behind the giant silt and gravel club sandwich sitting out behind our fair city, in which case you can say "ha" to me, and I will be your most humble servant as always. . . FR


I wrote to, and got a quick response from Ken Klein of Thompson Rivers University. Ken is the resident geologist at TRU and he writes:

I would have to look at the glacial debris to determine if it was a delta or ice deposited - my best guess from the picture is glaciofluvial delta deposits covered by lake sediments then more delta and then more lake sediments. Glacial activity in the interior was very cyclic with many periods of warm alternating with cold - hence the researched salmon remains of about 17-19,000 years of age. Water and Ice levels fluctuated with deltas being inundated with rising water and lake deposits....then becoming exposed and recovered with delta material - if the coarser material is glacial ice deposited till then it simply marks advance, retreat, melt, advance, retreat, melt etc........that is all I can attest to from the photo....Ken

So I guess I was somewhat close is my guess-timation I just did not know that so many glaciers visited our area.

1 comment:

  1. 1, Where is this in relation to the glacial "ice dam" in the area around the Kamloops Thompson/N. Thompson confluence? Does Frances Vyse have a comment on this.

    2. I've noticed (from an untrained non geologically educated but interested perspective) that in the western Savona area that glacial deposit near where the Thompcom River and the Deadman Creek/River, is - there is round rocked/glacially deposited 'stuff. One wonders where the river versus the glacially deposited begins/ends.

    Lots of layers/deposits between 'here and there. Would be interested in taking part in the study - if KNC has one planned.


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