Viewing post #2305950 by Rockcozy

Found a couple of research papers arguing for dust *deposition* on skree-covered slopes, e.g. :

The formation of soils on hillslopes mantled with stony colluvium are commonly viewed as having formed through the in-situ weathering of the stony colluvium. However, like pavements, mantles of coarse, stony colluvium are effective dust traps that provide the long-term stability required for advanced development of thick, fine-grained soils. This process contributes to the evolution of smooth, vegetated, curvilinear slope profiles. In each of these examples, the accumulation of dust has a profound influence, not only in soil formation, but also on the development of dominant landform characteristics.

- from McAuliffe, McFadden and Hoffmann, 2018, Role of Aeolian Dust in Shaping Landscapes and Soils of Arid and Semi-Arid South Africa, Geosciences v. 8 n.5 171. (source: https://www.mdpi.com/2076-3263...)

This chart shows how variable the soil conditions can be:
From amazing study on microhabitats in the succulent Karoo and Knersvlakte by Schmiedel and Jürgens (1999) Community structure on unusual habitat islands: quartz-fields in the succulent Karoo, South Africa. Plant Ecology 142, 57-69. (source: https://link.springer.com/arti...)


The "stone content" is weight percent of stones greater than 2 mm in diameter so that is a minimum estimate of how much inorganic content there is. It seems like lots of people mix their soils by estimated volume rather than weight so actually I'm not sure how that would translate if you are using volume.