Soils of Caribou-Poker Creeks Research Watershed

During the Illinoian and Wisconsin glaciations, large amounts of glacial silt were deposited in the braided river channels of the Yukon and Tanana Rivers to the north and south of the Yukon-Tanana Uplands. Southerly winds transported this silt and deposited it in the uplands as loess. The thickest loess deposits in the area are on south-facing slopes and in valley bottoms immediately adjacent to the Tanana River. In CPCRW, there is a but a thin cap of loess on most sites.

Rieger et al. (1972) identified seven soils series in the reasearch watershed (Table 1, Figure 1). These seven series can be grouped into two general categories: permafrost-dominated soils that are poorly drained and have high moisture and ice contents, and well-drained, permafrost-free soils (Figure 2). See permafrost page for more information.
 

Table 1. Description of soil types found in Caribou-Poker Creeks Research Watershed.
Soil Series	USDA Texture	Drainage	Permafrost	Location	% Area
Bradway	Stratified silt loam and loamy sand	poorly drained	shallow	flood plain	1.9
Ester	Silt loam	poorly drained	shallow	steep north-facing slopes	19.1
Fairplay	Silt loam and gravelly silt loam	mod. well drained	none	high ridges above tree line	21.9
Gilmore	Silt loam, gravelly silt loam, and very gravelly silt loam	well drained	none	south-facing slopes	11.5
Karshner	Stratified silt loam, silt loam, very gravelly silt loam, and very gravelly loamy sand	poorly drained	shallow	narrow flood plains in upper channels	1.7
Olnes	Silt loam and very gravelly silt loam	well drained	none	south-facing slopes	39.5
Saulich	Silt loam	poorly drained	shallow	foot slopes of hills	4.4