Actual thickness of permafrost vs theoretical maximum possibly permafrost thickness
I could not recover my account so here is some additional information for you. This area is Newfoundland and Labrador.  The maximum possible thickness was calculated by that equation I gave up above

Material, Max Possible Thickness, Actual Permafrost Thickness:
granite, 75m, 0m
sandstone, 150m, 1m,
glacial till, 113m,1m
esker gravel, 188m,0m
marine silt, 375m,15m
river sand, 225m, 0m
fen pea,t 300m, 10m