According to the actual definition of A horizon in the Soil Survey manual (2017), they are C horizons even with some organic matter is present. See below the last sentence of the definition below Definition of the Soil Survey manual (2017): A horizons are mineral horizons that formed at the soil surface or below an O horizon. They exhibit obliteration of all or much of any original rock sby Jérôme Juilleret - Soil Taxonomy Forum
My understanding from the table 3.2 page 134 from the Soil Survey Manual (2017) is that you take the longest axis in case of flat fragments. So in your example, I will classify it as "Stones". Best regards.by Jérôme Juilleret - Soil Taxonomy Forum
Dear soil taxonomists, If you want to see example of Buol's Soil Taxonomy like classification for Saprolite, look at our paper "Where are we with whole regolith pedology? A comparative study from Brazil " published in the South African Journal of Plant and Soil. 50 free eprints available at this link (paste into your browser): http://www.tandfonline.com/eprint/iAPrrq8qjXy4bby Jérôme Juilleret - Soil Taxonomy Forum
I will say in theory yes, but using a "geomechanical approach" can be sometimes in contradiction with the genesis. As an example, some sandstones can be weakly cemented at the basis. So in this case, your sandstone is geneticaly a Bedrock but will be recognize as a Saprolite. Indeed, we should keep in mind that a lot of sedimentary rocks were previously reworked soils or saprolite.by Jérôme Juilleret - Soil Taxonomy Forum
Thank you, indeed Saprolite is a general term for weathered bedrock in geosciences, but according to "soil standard", we need a more detailled definition with treshold diagnostics. In my reflexion, the "entry door" into the Solum is the Cambic horizon where one of the principal diagnostics is the occurence of a pedic structure (> 50 %) compare to Rock structure. So tby Jérôme Juilleret - Soil Taxonomy Forum
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 intracrby Jérôme Juilleret - Soil Taxonomy Forum
Dear Kenneth, I hope you remember me from the WRB Irish excursion last year. You have answered correctly, however I found the opportunity to annouce that we published a new paper on (C and R layers) subsolum classification in geoderma. Regards You can find it here:http://www.sciencedirect.com/science/article/pii/S0016706115300604 Abstract As soil surveys were traditionally condby Jérôme Juilleret - Soil Taxonomy Forum