Edward J. Ciolkosz

Soil development in till of various ages in northeastern Pennsylvania

Abstract Eleven well-drained soils formed in till parent materials of varying ages in northeastern Pennsylvania were studied to determine changes in the soils with time. Four profiles (three Lackawanna and one Bath) were formed in Woodfordian till (15,000 yr B.P.), and two (Leck Kill) were formed in Altonian till (>28,000, 75,000 yr B.P.). In these soils, the extractable iron oxide, extractable aluminum oxide, and kaolinite contents increase with age, as do the total clay and fine/total clay ratio. With increasing age, the maximum accumulation of these constituents is found deeper in the profile. The extractable silicon oxide distribution is constant with depth, but it decreases in overall amount with time. Gibbsite is found only in small amounts in the A horizon of Altonian soils, but occurs throughout the profile of pre-Wisconsinan soils, although only in small amounts. In general, differences were found in these soils which separated them into three groups representing varying degrees of soil development. A regression equation was derived to predict the age of soils formed from the Altonian till based on a “clay accumulation index” value for soils of known Woodfordian and Holocene ages. The equation log Y = 1.80 + 0.992(log X ) best fit the data, with an r 2 value of 0.913. Using this equation, a mean age of 41,000 yr was calculated for the Altonian soils. This date was used to derive a second equation to predict ages for pre-Wisconsinan soils. The equation with the highest r 2 value (0.934) was log Y = 1.81 + 0.998(log X ). Dates for soils developed in the White Deer till and the Laurelton till of the pre-Wisconsinan stage were calculated to be 86,000 and 91,000 yr B.P., respectively. These dates fall within ages estimated for the Sangamon Interglaciation and thus would appear to be too young for pre-Sangamonian materials. The probable reason for the “too-young age” is that the C-horizon material of the pre-Wisconsinan soils was weathered and did not provide an accurate estimate of clay accumulation for the prediction equation.

Slope gradient and aspect effects on soils developed from sandstone in Pennsylvania

Abstract This study was initiated to determine the basic characteristics and genesis of soils on gentle to very steep slopes on two contrasting slope aspects. Two transects, a southwest (SW) and a northwest (NW) transect, were laid out on a sandstone ridge across the summit and steepest convex shoulder positions. The thickness of the O, A and E horizons was not related to slope gradient across soils on all slope gradients and aspects. This indicates that the present rate of soil formation is greater than erosion, the influence of erosion on steep slopes could be off-set by lateral movement of through-flow water above the B horizon, or the process of tree throw masks slope gradient effects. Solum depth, B horizon thickness, clay, Fe, and Al indexes decreased with increasing slope for both the NW and SW aspects. Organic carbon index decreased with increasing slope for the SW aspect. Decreases in effective precipitation over relatively larger surface areas at steep versus lower slope gradients, a longer influence of periglacial erosion following the Wisconsinan glacial advance, and present slow but significant soil creep could cause these differences in soil development across the slope. Solum depth, B horizon thickness, clay, Fe, and Al indexes showed a smaller decrease across the NW compared to the SW slope. Organic carbon did not decrease across the NW slope. The E horizon was also slightly thicker on the NW compared to the SW slope. These aspect differences were probably caused by less evaporation on “shaded” NW compared to “sunny” SW slopes which produce generally higher moisture levels and more effective eluviation and illuviation on the NW slope.

Geochemistry of radium in soils of the Eastern United States

Abstract The abundance and chemical/mineralogical form of 226Ra, 238U and 232Th were determined on samples of soil and associated vegetation at 12 sites in the eastern United States. Progressive, selective chemical extraction plus size fractionation determined the abundance and radiometric equilibrium condition of these nuclides in 6 operationally defined soil fractions: exchangeable cations, organic matter, “free” Fe-oxides, sand, silt, and clay. In soils, profile-averaged 226Ra/238U activity ratios (AR) are within 10% of unity for most sites, implying little fractionation of U and Ra when the entire soil profile is considered. However, 226Ra greatly exceeds 238U activity in most surface soil (AR up to 1.8, av 1.22), in vegetation (AR up to 65, av. 2.8), in the exchangeable+organic fraction (AR up to 30, av. 13), in some soil Fe oxides (AR up to 3.5, av. 0.83) and in the C horizons of deeply weathered soils (AR up to 1.5). A major factor in Ra behavior is uptake by vegetation, which concentrates Ra>U and moves Ra from deeper soil to surface soil. Vegetation is capable of creating the observed Ra excess in typical surface soil horizons (AR up to 1.8, av. 1.22) in about 1000 a. Of the total Ra in an average A horizon, 42% occurs as exchangeable ions and in organic matter, but only 6–8% of the parent U and Th occur in these soil forms. In contrast, U is slightly enriched relative to Ra in Fe-oxides of A horizons, implying rapid chemical partition of vegetation-cycled U and Ra. In deeper horizons, transfer by vegetation and/or direct chemical partitioning of Ra into organic and exchangeable forms provides a source for unsupported 226Ra in Ra-rich organic matter, and leaves all soil minerals Ra-poor (AR=0.73). Organic matter evidently has a strong affinity for Ra. The phenomena discussed above are relevant to evaluation of indoor Rn hazard, and behavior of Ra at sites affected by radioactive waste disposal, phosphate tailings, Ra-rich brine, and uraniferous fertilizer.

Distribution and genesis of soils of the northeastern United States

Abstract The soils of the northeastern United States (central and northern Appalachians) north of the glacial border are Spodosols, Inceptisols, Alfisols, and some Entisols and Histosols. These soils are relatively young (12–18 ka). Climate (frigid soil temperatures), parent material (acidic, sandy), and vegetation (conifers) are the major soil forming factors affecting the genesis of the Spodosols, while parent material (calcareous material) is a determining factor affecting the genesis of the Alfisols. The Inceptisols of southern New England are slightly different (better developed cambic horizon) than those of the Appalachian Plateau. The genesis of the Alfisols of the unglaciated Appalachian Plateau and Triassic Lowlands are also significantly influenced by carbonates and basic minerals in their parent material. Ultisols are found only south of the glacial border. Ultisols on the Appalachian Plateau and in the northern Ridge and Valley are young soils and should be identified as parent material Ultisols, while those of the southern Ridge and Valley, Piedmont and Coastal Plain show significant soil development and should be identified as genetic Ultisols. The soils south of the glacial border, on steep slopes, have been affected significantly by erosion during the cold cycles of the Pleistocene, while soils on gentle slopes have been affected to a lesser degree. Much of the material eroded during the Late Pleistocene has accumulated on lower sideslopes as colluvium. The erosional and depositional processes have resulted in a complex mosaic of moderate to well developed soils on the more stable landscape surfaces, and moderate to weakly developed soils on the erosional and depositional surfaces.

CHARACTERISTICS, GENESIS, AND CLASSIFICATION OF PENNSYLVANIA MINESOILS

This paper reports on 24 nontopsoiled, noncultivated minesoils described and sampled in Pennsylvania. The minesoils varied in age from 1 to 29 years. They all have high rock fragment contents (40 to 60% in the surface and >70% in the subsoil). The lower content of rock fragments in the surface plus a higher content of small fragments in this zone compared with the subsoil indicates that some weathering has taken place. Particle size data indicate no significant eluviation, although some clay films were observed in subsurface horizons. The morphology indicates weak profile development, with the majority (21 of 24) of the minesoils having sola of 50 cm or less. Morphological data also indicate that the solum is developing at a rate of about 1.6 cm per year. Soluble salts, primarily gypsum, were found in many of the soils, and their concentration increased with depth, exceeding toxic levels in some soils. Organic carbon data showed no trends that could be evaluated. The iron oxide content of the minesoils was relatively high and indicates rapid oxidation and some inherited free iron oxide. The pH of most minesoils was low, and the majority of them had at least one horizon with a pH of < 4.0. Thus the majority of these weakly developed soils have in the past and are currently undergoing a significant phase of acid-sulfate weathering. Although they were undergoing acid-sulfate weathering, we noted no effect of the weathering on the clay mineralogy. The majority (79%) of the minesoils would be classified as Entisols, and the remaining 21% have weakly expressed cambic horizons and should be classified as Inceptisols.

Gaseous diffusion and permeability in four soil profiles in central Pennsylvania

Bulk diffusion and gaseous permeability coefficients were measured in situ in most morphologic horizons of four soil profiles in central Pennsylvania. Such data are rare in the literature. From the eluvial to the illuvial horizons of individual soil profiles, bulk diffusion coefficients generally decrease by nearly an order of magnitude, and gaseous permeability coefficients decrease by about two orders of magnitude. In all four profiles, the diffusion and permeability coefficients are higher in the upper, coarsely textured horizons than the lower horizons and, at corresponding depths, in more coarsely textured than finely textured pedons. The accuracy of the diffusion coefficients is confirmed by the similarity of an observed radon-222 (Rn) concentration profile to that estimated using the measured diffusion coefficients and a two-dimensional finite difference model. Several published methods of estimating bulk diffusion coefficient from air-filled porosity are statistically compared with the data following log transformation. Although all the methods tested were highly correlated to the in situ data, the estimates of Millington (1959, Science, 130:100–102) and Sallam et al. (1984, Soil Science Society of America Journal, 48:3–6) produced values most similar to those measured. Logarithmically transformed values of the bulk diffusion and permeability coefficients are highly correlated with each other for both our data and previously published data. This relationship holds true for eight different soils measured by separate researchers using different methodologies and appears to be generally applicable. Since the permeability values encompass a larger relative range than the diffusion values, measured gaseous permeability coefficients can be used to estimate bulk diffusion coefficients. This empirical approach to estimating diffusion coefficients is useful in that, in addition to air-filled porosity, permeability reflects the continuity and tortuosity of the air-filled pore system. Since the continuity and tortuosity of air-filled pores affect the diffusion coefficient, and neither of these properties are directly reflected in estimates based on air-filled porosity, estimation of diffusion coefficient using permeability accounts for important soil properties not directly accounted for with methods based on air-filled porosity alone.

Quaternary soil chronosequences on terraces of the Susquehanna River, Pennsylvania

Abstract Susquehanna River terraces are used to establish time lines along a 150 km reach of the river, from the Lower Piedmont to the edge of the Appalachian Plateau. This is achieved by generating soil chronosequences at two locations — Marietta, PA, in the Lower Piedmont, and Muncy, PA, near the glacial border on the boundary between the Valley and Ridge province and the Appalachian Plateau. These sites preserve the most complete record of fluvial incision on the Susquehanna River with flights of seven Quaternary terraces ranging in elevation from 3 m to 51 m above the modern river. Soil characteristics used to develop the soil chronosequences include complexity of horizonization, thickness of B horizon, clay content of B horizon, soil color, CBD extractable Fe, Al, and Mn, total extractable Fe, and clay mineralogy. Terrace age constraints are based on soil development, correlation to regional glacial stratigraphy, correlation to dated fluvial and glaciofluvial deposits, and by paleomagnetic analysis of sediments. Terrace ages at the Muncy site range from modern (

Genesis of soils and landscapes in the Ridge and Valley province of central Pennsylvania

Abstract The characteristics and properties of the soils on the ridge tops, footslopes, and adjacent limestone valley areas in the Ridge and Valley of central Pennsylvania have been strongly influenced by their parent material and geomorphic history. The ridge top soils have developed in sandstone colluvium which mantles sandstone residuum. The upper part of the original residual ridge top soil was truncated during late Wisconsinan time and then covered with local colluvium or it was cyroturbated. These sandstone parent materials have been stable since the late Wisconsinan and have sandy skeletal Dystrochrepts and Haplorthods developed in them. The Haplorthods are minor soils and are associated with local concentrations of coniferous vegetation. During the late Wisconsinan, the sandstone colluvium also moved downslope and was mixed with bedrock and residual material from shale and limestone and deposited on the footslope over a pre-Wisconsinan soil developed in older colluvium or limestone residuum. The footslope surface colluvial soils vary in texture and drainage because of their parent material, their location in discharge areas, and fragipan development. The age of the brown surface colluvium is considered late Wisconsinan and the age of the pre-Wisconsinan buried soils is not known. The buried soils bright red (rubified) color and argillic horizon indicate a much greater degree of soil development than noted in the brown surface colluvium, and its age may be correlated with isotope stage 6. The soils developed at the surface in the colluvium are mainly Ultisols although some poorly drained soils, particularly in limestone material, are Alfisols. The Ultisols are parent material Ultisols and the poorly drained Alfisols have a high base status in their parent material or were recharged with bases from the groundwater. The soils of the limestone valleys are developed in residuum. The residuum accumulated from the insoluble residues after the CaCO 3 was leached from the bedrock. If the residuum is thick (2 to 3 m), the soils date back many hundreds of thousands of years, but are still classified as Hapludalfs. In addition to being old, the surface of the Hapludalfs has been modified by periglacial truncation and the addition of eolian materials. These processes have given the upper 50 cm of the Hapludalfs a late Wisconsinan age but the bulk of the B horizon is many thousands of years older. Eolian material has also been added to the ridge top soils as well as the colluvial soils. The mineralogy of all the soils in this landscape, including the buried paleosols, does not show significant clay mineral weathering. This appears anomalous considering the degree of oxidation of the buried paleosols and the limestone soils and their estimated age.

The effect of organic carbon, temperature, time, and redox conditions on soil color.

This study was undertaken to observe the effects of organic carbon content (3.2, 9.6, and 15.4 g kg−1), organic carbon quality (26 and 107 g kg−1 nonstructural carbohydrates), temperature (5, 15, and 25°C), and time (7, 14, 21, and 35 wk) on color changes in soil material (originally 7.5YR 5/6) under alternating oxidizing and reducing conditions in the laboratory. Hues of the mottle and matrix colors were strongly influenced by organic carbon content and ranged from 7.5 YR to 2.5Y as organic carbon was added. Temperature and time influenced matrix color and mottle hues to a lesser extent. Mottle and matrix color values were altered but did not exhibit any trends with organic carbon, temperature, or time. The chromas of the mottle and matrix colors were strongly influenced by organic carbon content. Mottle chromas were strongly influenced by organic carbon content. Mottle chromas ranged from 8 to 1 whereas matrix chromas ranged from 6 to 3. Temperature and time influenced mottle and matrix chromas to a lesser extent. The areal extent of color changes increased with organic carbon content, temperature, and time. The increased yellow (10YR and 2.5Y) components, higher values, and lower chroma of the colors was attributed to hematite dissolution, which allowed goethite and non-iron oxide minerals to influence the observed colors more strongly. A decrease in color values was attributed to new precipitates on existing oxide or silicate mineral surfaces.

SOILS DEVELOPED FROM COLLUVIUM IN THE RIDGE AND VALLEY AREA OF PENNSYLVANIA

Soils developed from colluvium are found on the side slopes of all the major and many of the secondary ridges in the unglaciated Ridge and Valley area of Pennsylvania. The texture of these soils varies from sandy loam to clay and, for the most part, has been inherited from the parent material. Vertically within these soils there are many textural changes. These changes are the result of argillic horizon development and textural heterogeneity of the parent material. These soils are well leached in the well- drained sites and less thoroughly leached in the more poorly drained sites. Fragipans occur in all the medium textured soils, but not in the finer textured ones or in the soils that have significant limestone influence in their parent material. The clay mineral content of these soils indicates significant illite weathering with a trend of less intensive weathering with depth and with increasingly poorer drainage. The presence of argdlic horizons, fragipans, significant illite weathering, and appreciable leaching indicates that these soils are moderately well developed. This implies that the landscapes on which these soils are found are relatively stable today, probably dating back to the Wisconsinan glacial time.