Soils

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Parent Material

Mineral soils of the Marcell Experimental Forest are derived from glacial processes that occurred during the Wisconsinan glaciation, which began about 75,000 years ago. During this time, the Laurentide Ice Sheet covered much of North America. Minnesota was at the edge of the ice sheet, and thus was not always completely covered with ice. Three major ice lobes advanced, retreated, and readvanced across northcentral Minnesota during the Wisconsinan period, including the Winnipeg lobe (previously identified as the Wadena lobe), the Rainy lobe, and the Koochiching lobe (previously identified as the St. Louis sublobe of the Des Moines lobe). Winnipeg basal till lies immediately over the Ely greenstone and granite bedrock. Varying thickness of Rainy lobe drift lies above the basal till. Its texture ranges from fine sands to gravels, and it is exposed at the surface over about 25% of the MEF. It is brown, and lacks calcium carbonate except near its upper boundary where the more recent, slightly calcareous, Koochiching till overlies it. Visit the Minnesota Geological Survey for more information.

Upland Soils

Soils derived from Rainy lobe drift are mainly loamy sands (Menahga and Graycalm series, Typic Udipsamment and Alfic Udipsamment, respectively). Koochiching till caps the deep sandy drift of the Rainy lobe over 75% of the MEF, and ranges from 3 to 5 m thick. The upper 20 to 30 cm are characteristically fine sandy loam derived not as direct glacial till, but as eolean loess blown from dry hills exposed after glacial melt. Where Koochiching till dominates, the upland soils are primarily composed of weakly calcareous fine sandy loams (Warba and Nashwauk series, Glossic Eutroboralf and Typic Glossoboralf, respectively).

Peatland Soils

The peatland soils at MEF are derived from two processes: paludification and terrestrialization. The bogs are derived from ice block depressions and the subsequent filling in of the shallow pond or lake by organic materials (terrestrialization). The fen is likely derived from the slow creep of peat across a flat landscape due to the presence of water above impermeable layers (paludification). Both bog and fen systems at MEF are likely to be influenced somewhat by both processes. Peatland organic soils vary in properties based on decomposition state. Soils range from highly decomposed Typic Borosaprists and Haplosaprists to moderately decomposed Typic Borohemists and Haplohemists (Mooselake, Lupton, Loxley, and Greenwood series).