Fat to lean clay in a single, discrete soil deposit
Fat to lean clay in a single, discrete soil deposit
(OP)
Is it possible to have that range of plasticity from an otherwise homogenous clay source? I'm talking range of plasticity index from less than 10 to nearly 80, and range of liquid limit from 30 to greater than 100. Is there a method of deposition, mineralogy, or chemistry that could explain the wide variance, or do I have suspect data?





RE: Fat to lean clay in a single, discrete soil deposit
As I started reading I thought, "Sure, why not?" You do have quite a range, allthough it might be correct. Also to consider is what sort of geologic setting are you in?
RE: Fat to lean clay in a single, discrete soil deposit
RE: Fat to lean clay in a single, discrete soil deposit
This is the same geologic formation? or Soil Unit?
Very little visual differance in the samples?
I have dealt with such extreme changes in clay plasticity in the lowest members of the Mancos Shale (Km) in Western Colorado. The variation is within 20 feet vertical (differant strata) and 1000 feet horizontally (facies change).
RE: Fat to lean clay in a single, discrete soil deposit
RE: Fat to lean clay in a single, discrete soil deposit
This may account for a lot of the variation, and lack of a distinct pattern.
I have seen this on a much smaller scale on a landfill project. I had the benefit of watching the excavation though, and we had a rather defined channel from a dried creek. Nice fat clay soil liner material in the old bed, and nasty sandy, non-plastic silts on the sides. If only the contractor would have used a trackhoe vs. scrapers, we would have had enough material.
Anyway, this is the same concept on a lot smaller scale. You are dealing with a much longer sedimentation period, and wider area with flood plane, etc.
RE: Fat to lean clay in a single, discrete soil deposit
Where are you on the Slope? 20 years ago, I spent a fair bit of time up there, Barrow, Kaktovic, Nuisqet, Ataqsit, Point Lay, etc. (I've forgotten how to spell the village names, oh well. . . ).
Good luck.
f-d