Re: What is Saprolite?

Dear John,

It would be nice if you can really define more precisely what is Saprolite in SSM and in Keys to Soil Taxonomy.

The only reference that I found in US came from the (Soil Science Glossary Terms Committee ,2008):

Saprolite: Soft, friable, isovolumetrically weathered bedrock that retains the fabric and structure of the parent rock exhib-
iting extensive intercrystal and intracrystal weathering. In pedology, saprolite was formerly applied to any unconsoli-
dated residual material underlying the soil and grading to hard bedrock below.

In Juilleret et al (2016), we (re)defined Saprolite under the name of saprolithic material according to Soil science.

For classification purpose, Saprolithic layer show the following diagnostics:

1. does not meet the requirements of any other diagnostic horizon, or
layer or other diagnostic soil characteristic, and

2. lacks evidence of accumulation of transported material; and

3. has a rock structure in > 50 % (by volume) and soil aggregate structure
in < 50% of the volume of the fine earth fraction, or a single
grain or massive structure, and

4. can easily be dug with a spade or with a pickaxe if the material is
slightly consolidated in > 75% of the volume, or when air-dry, more
than 50 % (by volume) will slake in water within 1 hour, or

5. roots may be present in the matrix and/or along remnant geogenic
features, and

6. has a thickness of at least 25 cm.


Cheers

Jérôme Juilleret

References:

Juilleret J, Dondeyne S, Vancampenhout K, Deckers J, Hissler C. 2016. Mind the gap: a classification system for integrating subsolum into soil surveys. Geoderma 264: 332-339.

Soil Science Glossary Terms Committee (SSGT). 2008. Internet glossary of soil science
terms.