Soil Color Ideas

Premise

Soil color generally varies in a predictable pattern with depth according to surface vegetation, clay mineralogy and parent material. Highly contrasting parent geology influences soil color within Pinnacles via four main processes:

  1. Original color of parent material
    sedimentary sources: grey, yellow, white
    granitic sources: yellow to orange
    volcanic sources: pink, orange, white, green
  2. Landscape age
    older landscapes generally have redder hues (Fe-expression) from longer chemical weathering
  3. Particle size distribution of parent material and the resulting field capacity of a soil formed from it
    coarse textures result in lower field capacities, limiting vegetation growth and subsequent accumulation of organic matter in the surface horizons
  4. Weathering rate of parent material
    sedimentary materials derived from granitic sources (grey to yellow hues) have high levels of quartz and are therefore less susceptible to chemical weathering than volcanic rocks (redder hues)

pinn_luv.png
Soil colors from Pinnacles: Moist colors in the L*U*V* color space (629 horizons).

Query Samples

All Horizons along with horizon thickness



    
    

Horizon Thickness-weighted Average for Subsurface Horizons



    
    

Pedon Color (spatially) Averaged within 500 meter grid, from profile thickness-weighted average



    
    

Visualization in R

Setup R environment



    
    

pinn_colors_0.png
Pinnacles Soil Color Map 1

Plot colors from all horizons, for all pedons. Note that a small amount of noise is added to the (x,y) coordinates of each pedon, so that the colors from each horizon do not overlap. Thinner horizons are depicted with a more transparent color.



    
    

pinn_grid_colors.png
Pinnacles Soil Color Map 2

 
Plot colors from all horizons, for all pedons. Note that a small amount of noise is added to the (x,y) coordinates of each pedon, so that the colors from each horizon do not overlap. Thinner horizons are depicted with a more transparent color.



    
    

 
Colors of Pinnacles



    
    

Can soil color be used to infer parent material source?
Approximate identification of parent material source based on soil colors. Note that this is a very coarse estimation, especially since large regions of the sedimentary materials were originally derived from granitic sources. The general trend visible in the clustering does match a rough approximation of the park geology.

pinn_color_classes.png
Pinnacles Soil Color Clustering Idea 1: PAM clustering of mean subsoil color (horizon thickness-weighted) for 170 pedons.