From the Soil Micromorphology Slide Collection

Data for the horizon
Horizon sampled: Btb Depth sampled: 78-115 cm
Physical and chemical data available: See attached
Macromorphological description of horizon: 10 YR 5/4 dry, 10 YR 4/4 moist, loamy fine sand; weak medium subangular blocky structure
Micromorphological description of horizon: The coarse and fine constituents have a chitonic-gefuric related distribution pattern (Stoops and Jongerius, 1975). The skeleton grains are 0.2 to 0.3 mm in diameter. Most, but not all, have illuviation argillans at contacts with other grains. The argillans are as thick as 25 µm. Quartz and plagioclase are the dominant skeleton grains. The plagioclase is relatively unweathered.
The ratio of silt to clay is < 1 and silt + clay is slightly < 12%. Hence the section's related distribution pattern is chlamydic, but close to plectic, by the definitions of Brewer, Sleeman and Foster (1983).
The clays were inherited from the parent material. Weathering in the A and C horizons is about the same. The eolian sands are thought to be Holocene in age. A C-14 date of 7100 YBP for an horizon buried by eolian silts and sands within a few km of this site supports this view.

Data for thin section
Preparation of sample: Air dry
Thickness of section: 30 µm
Size of section: 25 x 40 mm

Soil Classification
U.S.: Sandy, mixed, thermic Typic Argiustoll

Elevation: 579 m MSL
Physiographic position: Undulating upland slope
Topography and hill slope position: NW facing 3% sideslope Parent material: Eolian sands
Soil climatic data and/or soil water balance: Mean annual precipitation-63 cm; ustic moisture regime; mean annual temperature = 13 C; mesic
Vegetation: Range land

Data for 35-mm slide
Frame length: 2 mm
Light mode: Plane polarized (RDP7); cross-polarized light (RDP8)

Unpublished report of the National Soil Survey Laboratory. USDA-SCS, Lincoln, NE.
Brewer, R., J.R. Sleeman, and R.C. Foster. 1983. The fabric of Australian soils. p. 439-476. In Soils: An Australian viewpoint. CSIRO, Melbourne and Academic Press, London.
Stoops, G. and A.J. Jongerius. 1975. Proposal for a micromorphological classification in soils materials. 1. A calssification of the related distributions of coarse and fine particles. Geoderma 13:189-200.
Source - W.D. Nettleton

Slides RDP7 and RDP8. Soil Science Society of America, 1993. A Reference Slide Collection for Soil Micromorphology. SSSA, Madison, WI.