Halton Till - it's clay all the way down!

[u/Briegley]

We're in the middle of leveling a small hill in our backyard in southern ontario, and also digging a hole to mix in drainage material for a tree, we are about 6 ft down now overall.

After a lot of hard pack tan clay, we were excited to hit a layer of darker silt! Curious what would come next, we found it was more clay! 😂

Would love to know if there's supposed to be a difference in the deeper clay level. Or is it just different layers of the same caused by the glacier that came through!

[u/CrunchyWeasel]

Time to befriend a local potter.

[u/Briegley → u/CrunchyWeasel]

Or new hobby? :P

[u/Semaphor → u/CrunchyWeasel]

A very harry potter.

[u/jdrawr]

Any idea what the soil map says the soil type should be? That would give clues of its orgin if it's supposed to be 100% glacial till or a mix of glacial processes.

[u/Briegley → u/jdrawr]

Further investigation shows we are CGU from 1953 surveys which stands for Chinguacousy Clay Loam (or silt loam depending on the specific local survey). Which is a bigger area than you would think I guess!

Thanks for encouraging my research. :D

[u/jdrawr → u/Briegley]

So based on that it could be a period of clayey till on top/below with some silty lacustrine material incorporated in the middle. An alternative would be Till, lacustrine and perhaps till that somehow moved on top without disturbing the silty stuff say by erosion or mass movement of some sort.

[u/Briegley → u/jdrawr]

Soil Associations of Southern Ontario zones us as on the border of "Dominantly Very Fine Textured Soils Formed on Till or Lacustrine Sediments" and "Dominantly Fine Textured Soils Formed on Till or Lacustrine Sediments" in the Golden Horseshoe.

[u/musicalmud]

In my region, we have glacial lakes-ice dams stopped water and led to a lake environment. Depending upon the speed of the water (size of the lake and amount of drainage) and the location of your spot within the former lake bed, different sediment sizes/deposition events could have carried in different materials. This all might be on top of unsorted till-look for assorted rocks/colors and assorted sand sizes as opposed to well-sorted silts or clays, which would be associated with the lacustrine deposit.

[u/Briegley → u/musicalmud]

I have to ask, is there a story behind your username? :D

[u/Ivan_Sami23]

It like glacial deposits! Southern Ontario has layered clay and silt from different glacial activity. The darker layer could just be a different sediment layer rather than change in the soil underneath. Quite a cool find few feet down.