Soil Geochemistry

This alternative mitigation examined and synthesized soil geochemistry at 45 historical archaeological sites in Delaware. The study provides information regarding appropriate applications of soil geochemistry at historic archaeological sites in Delaware using multi-element weak acid extraction techniques. Survey data sets indicate that soil texture analysis, and quantified soil attribute data on soil pH, cation exchange capacity (CEC), percent of organic matter by loss on iginition (OM by LOI), aluminum, boron, calcium, copper, iron, magnesium, manganese, phosphorus, potassium, sulfur, and zinc, at mimimum, should be analyzed as part of soil geochemistry analysis of anthropogenic soil chemical residues. Additional studies undertaken internationally also indicate that analysis of barium (Ba), cadmium (Cd), cobalt (Co), chromium (Cr), lead (Pb), mercury (Hg), molybdenum (Mo), nickel (Ni), nitrogen (N), rubidium (Rb); scandium (Sc), silicon (Si), sodium (Na), strontium (Sr), thorium (Th), titanium (Ti), vanadium (V) may also be useful. The data clearly indicate that multi-element soil geochemistry analysis is a viable, efficient, and critical tool to understand and interpret aspects of archaeological sites that may not be apparent from an analysis of cultural features and material culture patterning alone. Soil geochemistry must be examined in conjunction with site specific environmental data to form an appropriate context to evaluate and interpret data sets. Appropriate statistical analyses should also be applied to identify patterns in a site’s soil geochemistry to aid in site interpretation. Multi-element geochemical analysis of anthrosol deposits can be utilized to prospect for activity areas and cultural features, determine similarities or differences in feature functions at a site, and interpret spatial arrangement of activity areas within a site. While all soil samples should be taken with sterilized equipment, the methods and procedures for sampling a site (e.g. random sampling, grid interval sampling, feature sampling, horizontal sampling within a soil column) varies based on the types of questions soil geochemistry analysis seeks to address.

This alternative Phase III mitigation was conducted as part of DelDOT's State Route 301 mega project in northwestern Delaware. Funding was provided by the Federal Highway Administration.

Chemical safety of school playgrounds is very important for the health and well-being of students and it is expected that level of heavy metals [including toxic elements] be below acceptable [non-toxic] levels. The risk from accidental consumption of potentially toxic elements in playground soils is of concern to children’s health. Concentration of heavy metals is a very important factor in assigning type of land use. For example, Canadian Council of Ministers of the Environment [CCME] has published soil quality guidelines to help protect environmental and human health. These guidelines identify 4 types of land use in Canada: agricultural, residential/parkland, commercial, and industrial. Different concentrations of heavy metals are suggested for each land use.

A total of 73 samples were collected from playgrounds of 16 elementary schools in Brandon, Canada and analysed for major and light elements [Fe, Ti, Ca, K, Al, P, Si, Cl, S, Mg] as well as trace and heavy metals [As, Ba, Cd, Cr, Cu, Pb, Mn, Ni, Se, U, V, Zn]. The elemental relationships in these samples show that the data sets were predominantly influenced by natural geologic element dispersion and accumulation processes. Anthropogenic sources generally enrich individual [or small number of] elements and, as a result, distributions are disturbed and skewed towards higher values in natural systems. Lower values are commonly free from anthropogenic influences. This research shows that As, Ba and Cu are the only heavy metals in playgrounds of some schools in Brandon that are higher than, or close to, the values suggested by the Canadian soil quality guidelines.

Calcareous vertisol soil is the dominant agricultural
soil type and covers over 80% of the agricultural
cultivated land in Jordan. This type of soil is characterized
by its high pH and CaCO3 content, which made the heavy
metals including Zn to be oxidized and adsorbed onto soil.
Therefore, this type of soil is regarded as potentially Zn
deficient. The effect of Zn initial concentration and average
rainfall on the Zn adsorption and desorption from three
types of calcareous vertisol soils has been examined. The
amount of Zn adsorbed and desorbed at equilibrium
increased with increasing Zn initial concentration for each
of the three investigated soils. However, the percentage of
adsorption and desorption decreased as the initial concentration
of Zn ions increased. Moreover, results showed that
rainfall has no influence on the behavior of Zn in the calcareous
vertisol soils. Freundlich and Redlich-Peterson
models provide the best representation of the experimental
data, followed by the Langmuir model.

Paleosols (fossil soils) are abundant in the sedimentary record and reflect, at least in part, regional paleoclimate. Paleopedology thus offers a great potential for elucidating high resolution, deep-time paleoclimate records. However, many fossil soils did not equilibrate with climate prior to burial and instead dominantly express physical and chemical features reflective of other soil forming factors. Current models that use elemental oxides for climate reconstruction bypass the issue of soil-climate equilibration by restricting datasets to narrow ranges of soil properties, soil-forming environments and mean annual precipitation (MAP) and mean annual temperature (MAT). Here we evaluate a data-driven paleosol-paleoclimate model (PPM 1.0) that uses subsoil geochemistry to test the ability of soils from wide-ranging environments to predict MAP and MAT as a joint response with few initial assumptions. The PPM 1.0 was developed using a combined partial least squares regression (PLSR) and a nonlinear spline on 685 mineral soil B horizons currently forming under MAP ranging from 130 to 6900 mm and MAT ranging from 0 to 27 °C. The PLSR results on 11 major and minor oxides show that four linear combinations of these oxides (Regressors 1-4), akin to classic oxide ratios, have potential for predicting climate. Regressor 1 correlates with increasing MAP and MAT through Fe oxidation, desilication, base loss and residual enrichment. Regressor 2 correlates with MAT through temperature-dependent dissolution of Na-and K-bearing minerals. Regressor 3 correlates with increasing MAP through decalcification and retention of Si. Regres-sor 4 correlates with increasing MAP through Mg retention in mafic-rich parent material. The nonlinear spline model fit on Regressors 1 to 4 results in a Root Mean Squared Error (RMSE MAP) of 228 mm and RMSE MAT of 2.46 °C. PPM 1.0 model simulations result in Root Mean Squared Predictive Error (RMSPE MAP) of 512 mm and RMSPE MAT of 3.98 °C. The RMSE values are lower than some preexisting MAT models and show that subsoil weathering processes operating under a wide range of soil forming factors possess climate prediction potential, which agrees with the state-factor model of soil formation. The nonlinear, multivariate model space of PPM 1.0 more accurately reflects the complex and nonlinear nature of many weathering processes as climate varies. This approach is still limited as it was built using data primarily from the conterminous USA and does not account for effects of diagenesis. Yet, because it is calibrated over a broader range of climatic variable space than previous work, it should have the widest array of potential applications. Furthermore, because it is not dependent on properties that may be poorly preserved in buried paleosols, the PPM 1.0 model is preferable for reconstructing deep time climate transitions. In fact, previous studies may have grossly underestimated paleo-MAP for some paleosols.

To learn more about the internal layout of Inuit communal sod houses in Labrador and the anthropic impact of their occupation on the sedimentary matrix, a combination of
micromorphological and geochemical analyses was used to study three communal houses located at the archaeological sites Oakes Bay-1 and Uivak Point 1. Several anthropic indicators associated with Inuit occupation of these houses were identified. In particular, the presence of burnt bones and organic matter and the enrichment of the soil in sodium, organic phosphorus,and barium suggest a concentration of faunal and organic debris that could have been due to cooking activities. Scattering of several anthropic indicators throughout the houses may also have been due to cleaning events or natural and post-depositional processes. This tendency toward scattering made it impossible to identify specific activity areas in the communal sod houses under study, with the exception of House 1 of Oakes Bay-1. Nevertheless, despite being seasonal and sporadic, Inuit occupation of Oakes Bay-1 and Uivak Point 1 definitely impacted the sediment matrix of both archaeological sites.

The aim of the research summarized in this paper was to describe soil properties from different contexts at an excavated hilltop settlement (subsurface features with artefacts, subsurface features holding no artefacts, and several sets of samples from substratum), to determine possible anthropogenic indicators at this locality, and to assess what, if any, are the differences of soil properties taken from the features with artefacts and those holding no artefacts. For this aim, 43 bulk soil samples were collected and analyzed for 16 chemical elements, magnetic susceptibility, soil organic matter and inorganic carbon, and pH values. The results revealed several sets of anthropogenic markers, among which the most distinguished were P, Mn, Zn and MS anomalies. A correlation between the presence/absence of artefacts and soil properties has not been detected. Anthropogenic sets were confirmed for almost all features with artefacts and for the major part of features holding no artefacts; thus the altered soil geochemical properties for these features can be assumed as an important additional cultural marker beyond that given by the archaeological remains. A handful of features with artefacts in one of them failed to be recognized as bearing any human-related signal; taking into account the circumstances, with reasonable care, they were categorized as disturbances having no archaeological value. No unambiguous interpretation is suggested for the analyzed subsurface features; rather they were considered in assessing various scenarios of archaeological context formation.

Objective of this study is to use soil geochemistry surveys using statistical methods for the exploration of possibly gold mineralization related to Alakeçi listvenite area (Bayramiç, Çanakkale, Turkey). In the scope of soil geochemistry, about 350 soil samples were analyzed and evaluated for nine elements including gold. Element concentrations for Cu, Pb, Zn, As, Sb, Mo, Ni, Co and Au (all element except Au in ppm, Au in ppb) were 10-265, 10-90, 15-545, 5-800, 2-60, 4-8, 10-6300, 15-1255 and 40-300 respectively. The gold concentrations were comparatively detected in low value than important ore deposit and exhibited no correlation with other elements (except Mo). However, positive correlation was observed between Cu and Zn; Sb and As; Mo with As and Sb; Au and Mo; Ni and Co. In literature, Cu, Zn, As, Sb and Mo were widely used as pathfinder elements for exploration of gold mineralization. So, these elements were accepted as pathfinders in this study and their distribution maps were prepared. The element distribution maps for pathfinder elements and gold displayed remarkable zoning in the central to southeast site of the area connected with tectonic lines and lithological borders. So, in conclusion, this part in the area needs to be investigated in detailed with geophysics and drilling methods for blind gold mineralization.