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Geology topics

R. C. Severson

Publications and source records attributed to R. C. Severson.

At least 19 recordsLinked to original sources
USGS2001

Geochemical landscapes of the conterminous United States — New map presentations for 22 elements

Geochemical maps of the conterminous United States have been prepared for seven major elements (Al, Ca, Fe, K, Mg, Na, and Ti) and 15 trace elements (As, Ba, Cr, Cu, Hg, Li, Mn, Ni, Pb, Se, Sr, V, Y, Zn, and Zr). The maps are based on an ultra low-density geochemical survey consisting of 1,323 samples of soils and other surficial materials collected from approximately 1960-1975. The data were published by Boerngen and Shacklette (1981) and black-and-white point-symbol geochemical maps were published by Shacklette and Boerngen (1984). The data have been reprocessed using weighted-median and Bootstrap procedures for interpolation and smoothing.

Conterminous United States↗
USGS1995

The effect of acidic, metal-enriched drainage from the Wightman Fork and Alamosa River on the composition of selected wetlands in San Luis Valley, Colorado

The biogeochemistry of selected wetlands in the San Luis Valley, Colorado, was examined to assess the effect of acidic, metal-enriched water draining mineralized areas near and around the Summitville Mine. The sampling protocols, analytical methods, and chemical composition of water and stream bed sediment from the Wightman Fork and Alamosa River as well as water, surface sediment or cores, and rooted aquatic vegetation from wetland sites within and west of the Alamosa National Wildlife Refuge are presented. The data indicate that As, Co, Cr, Cu, Ni, and Zn are tracers of drainage from mineralized areas around the Summitville Mine. Sediments and aquatic plants in wetlands in the San Luis Valley that receive surface water from the Alamosa River tend to have larger concentrations of certain tracer elements (e.g., Co and Cu) than wetlands that receive water from other sources. Larger concentrations of Cu, Ni, and Zn in the sediments of wetlands receiving Alamosa River water appear to be related to the presence of larger amounts of Fe oxyhydroxides. However, there is little to no variation in the concentrations of tracer elements with depth in wetlands that receive Alamosa River water. This observation suggests that the geochemistry of these wetlands has not been significantly affected by recent mining activities at the Summitville Mine.

Colorado↗
USGS1988

Determining baseline element composition of lichens. I. Parmelia sulcata at Theodore Roosevelt National Park, North Dakota

Element-concentration baselines are given for Parmelia sulcata and associated soils. Parmelia chlorochroa was found sporadically and therefore only representative concentration ranges are reported for this species. Element data include (1) for lichens; Al, As, Ba, B, Ca, Cr, Cu, Fe, Hg, Mn, Ni, P, Sr, S, Ti, V, Y, and Zn; and (2) for soils: Al, Ba, Be, Ca, Cs, Cr, Cu, Fe, Hg, Mg, Mn, Ni, Nb, P, Pb, Sr, S, Ti, V, Y, and Zn. Very little (usually < 10 %) of the variability in the element data for lichen material occurs regionally (> 7.2 km); thus, P sukata is, in general, chemically similar throughout the park. This same uniformity was found for soil geochemistry. Numerous samples collected at close intervals would be required, therefore, to produce detailed element-concentration maps for P. sulcata and soils. No instances of elemental phytotoxic conditions were found; however, P. sulcata apparently possesses large concentrations of Ba, Cu, Fe, Pb, S, V, and possibly Zn.

North Dakota↗