摘要：Previous work has explored the contribution of bedrock weathering to soil formation in alpine environments of the northeastern United States. In contrast, the role of surficial sediments as a parent material has received little attention. This study investigated the development of alpine soils in relation to surficial sediments and bedrock in part of the Presidential Range of the White Mountains, New Hampshire, U.S.A. Published mapping of the study area indicates that five contrasting bedrock units are thinly mantled by glacial sediment, providing the opportunity to evaluate the relative importance of these two potential soil parent materials. Samples collected from 25 pedons were analyzed for a variety of physical, chemical, and mineralogical properties. Soil profiles have distinct Oa, A, Bw, and BC horizons. X-ray diffraction analysis reveals the presence of chlorite in soils above all bedrock formations, despite the absence of this mineral in several bedrock types. Trace element concentrations are relatively uniform for all soils with no clear relationship to underlying bedrock. Differences in median grain size are significant in soils over different bedrock formations; however, extractable cations, cation exchange capacity, exchangeable acidity, and other soil properties exhibit no significant differences. The overall similarity of soils above strongly contrasting bedrock formations indicates that these soils are forming in a homogenous mantle of glacial sediment deposited in the late Wisconsin, and that bedrock weathering does not contribute to pedogenesis to measurable degree in this setting. Preservation of glacial sediment in the study area may be a function of the amount originally deposited, reduced erosion rates on relatively gentle slopes, or another unidentified factor.
