Phosphate in man-made soils derives from people, their animals, rubbish and bones. Their animals excrete even more. Each of these pools can be extracted using progressively more aggressive chemicals. Some workers Eidt especially , think that the ratios between these pools can give information about past land use, and perhaps even dating. Whatever the method of getting the phosphorus from the soil into solution, the method of detecting it is usually the same.
In the lab, this is measured using a colorimeter, where light shining through a standard cell produces an electric current proportional to the light attenuation.
Librarian Administrator Sign In. These similarities in scale are apparent in both regional and site-specific studies. Trace element analysis of an inhumation from Sutton Hoo, using induc- tively coupled plasma emission spectrometry: an evaluation of the techniques applied to analysis of Acknowledgements organic residues. Archaeological Prospection Archaeol. Paul Goldberg Paul Goldberg.
In the field, the same reaction is used on detector sticks, which are compared to a colour chart. Phosphate concentrations can be plotted on archaeological plans to show former activity areas, and is also used to prospect for sites in the wider landscape. The particle size distribution of a soil sample may indicate the conditions under which the strata or sediment were deposited. Particle sizes are generally separated by means of dry or wet sieving coarse samples such as till , gravel and sands , sometimes coarser silts or by measuring the changes of the density of a dispersed solution in sodiumpyrophosphate, for example of the sample finer silts, clays.
A rotating clock-glass with a very fine-grained dispersed sample under a heat lamp is useful in separating particles. The results are plotted on curves which can be analyzed with statistical methods for particle distribution and other parameters. The fractions received can be further investigated for cultural indicators, macro- and microfossils and other interesting features, so particle size analysis is in fact the first thing to do when handling these samples.
Trace element geochemistry is the study of the abundances of elements in geological materials that do not occur in a large quantity in these materials. Because these trace elements' concentrations are determined by a large number of particular situations under which a certain geological material is formed, they are usually unique between two locations which contain the same type of rock or other geological material. Geoarchaeologists use this uniqueness in trace element geochemistry to trace ancient patterns of resource-acquisition and trade.
For example, researchers can look at the trace element composition of obsidian artifacts in order to "fingerprint" those artifacts. They can then study the trace element composition of obsidian outcrops in order to determine the original source of the raw material used to make the artifact. Geoarchaeologists study the mineralogical characteristics of pots through macroscopic and microscopic analyses. DURING the evaluation of a new type of metal detector on various archaeological sites in England during the past summer, it has been observed that the instrument is also sensitive to non-metallic features such as filled-in pits and buried hearths.
Instead of a conventional system of continuous sinusoidal currents and associated magnetic fields , this instrument uses repeated rectangular unipolar pulses; these are fed to a transmitter coil which in the present instance is square, of side length 1. The voltage induced in a receiver coil concentric with the transmitter coil is fed to a fast-recovery d.
Aitken, M. Le Borgne, E.
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By submitting a comment you agree to abide by our Terms and Community Guidelines. They help to provide farmers with a quick method of assessing their crops, at the same time as providing a detailed record of crop growth throughout the year. Comparing the image from the 27 February to the geophysical survey shown in Fig. This is interesting for two reasons; firstly, oilseed rape is not a crop well known for producing archaeological crop marks due to its low plant density and branching canopy. Secondly, during the winter, it is not common to gather aerial imagery because of poor weather conditions but also due to the expected lack of archaeological feature detection i.
Yet perhaps there is progress to be made from talking to farmers about satellite data, helping them to understand the variations seen from an agricultural, pedological and an archaeological stance without which, anomalies in satellite and other data may be wrongly associated. It may also be helpful for archaeologists to understand the possibilities that a range of crops may produce archaeological crop marks under certain conditions and at times of the phenological cycle not realised before. In addition to this is the obvious advantage that there is simply more temporal and spatial data out there which, if it can be accessed, could be used to enhance the archaeological record if interpreted correctly.
Results of a precision farming conductivity survey, with the data points used to interpolate the image. Courtesy of James Price. At the same time, archaeological geophysicists have developed a wide range of experiences using multiple near-surface geophysical methods to learn about the nature of archaeological sites.
No one method has become the sole tool for an archaeological geophysicist since flexibility is essential when surveying a wide range of site types.
Magnetic gradiometry is one of the most commonly used methods in the archaeological geophysics sector in most academic departments, commercial units and other organisations, but has not yet been subject to research in an agricultural context despite being noted as a method of potential Allred et al. An illustration of a conductivity survey is shown in Fig. In this interesting image, there are clearly some anomalies, yet without any more detailed survey, it could not be interpreted whether these anomalies were of archaeological origin or not.
Crucially, however, as a broad survey of the soil variability, this image has value for future archaeological work on the site, enabling an initial focus on areas of soil that are most variable and hold higher potential for archaeological activity.
During the early twentieth century, the Swedish agronomist Olaf Arrhenius gained extensive experience in phosphate surveys while working for a sugar beet company Lambert He was acclaimed as one of the first people to suggest phosphate surveys could be used to prospect for archaeological sites. Since then, phosphate surveys have fluctuated in their use within archaeology, but have continued to be essential for farmers to maintain soil nutrient levels.
Companies and farmers using precision farming methods take a detailed interest in soil geochemistry. It is important for them to monitor and adjust macronutrient N, P, K, Mg and micronutrient levels every few years according to what the crop is expected to need and the nutrients expected to leave the field with the crop Heege Little research has, however, been directed at the implications of these geochemical variations from an agronomic point of view.
As precision farming represents attention to detail in soils and crops, it seems there needs to be better understanding of how archaeological sites contribute to agronomic variation. Caesium magnetometer survey and interpretation courtesy of Historic England Linford et al.
There are several plausible reasons for this enhancement. The soil type here has developed on top of a chalk bedrock, with the rest of the field assumed to be on a greensand geology. This assumption, from existing soil maps, however has been found to not be a true representation of the soil variability within the field. Instead, there is a much more complex situation with a band of greensand curving around the visible archaeological features in the geophysical survey. The archaeological features themselves sit on top of a chalk promontory that fluctuates in depth with a mixed horizon boundary.
Therefore, it is possible that the elevated zinc concentration is coming from these chalk-based topsoils, but the digging of the henge has increased the amount of mixing of soil horizons, creating the affect that the henge shows more strongly than other areas on similar chalk-based topsoils. Adding in further complexity is a number of pits that surround the henge identified in aerial photographs and the geophysical survey and the possibility of other sources of zinc inputs into the soil such as through manures and other activities.
Due to only topsoil samples being studied in this instance, the mixing of the soil horizons could mean several different sources for this variation in zinc and until further research evaluates this in more detail, no firm conclusions can be made.
Yet, this example demonstrates the complex situation that archaeological sites present in relation to their effect on soil geochemistry and their relationship with complex soil variations; it also shows the potential benefits of high-resolution data that archaeologists have collected for our understanding of soil variations on an agriculturally relevant scale.
The growth and future of the global agricultural industry will almost certainly rely on better use of technology and better understanding of what farmers do, how they do it and what impacts that has. As part of this, knowledge of the soils that underpin crop growth and the archaeological remains that add to the variability of soils is crucial. From examples presented here, there seem to be many common interests between the archaeological and agricultural communities in the UK, with great potential for building archaeological evidence into modern agricultural management regimes.
It must also be recognised that this is not limited to just the UK; agricultural technology is becoming far more prevalent from South America to Asia, and the underlying connections between archaeological sites, soils and agricultural management will still exist, be it within different archaeological and agricultural systems. However, there are also some significant areas that warrant further discussion and research.
Not only is there a need to understand the causes of variability on such case study sites, whether archaeological or not, but also on practical aspects of accessing and using this data responsibly. Primarily, these ideas rely on the basis of access to data from farmers and agricultural companies.
On an individual case by case basis, archaeologists aware of these datasets could simply ask farmers whether they have any potentially useful data for example. This having been said, it may be that in some cases, farmers may not want to understand more about the archaeology in their soil for fear of interference in their farming operations for example. While certainly possible, it is also possible that where important sites have been designated to protect them, there is little actual evidence for their extents, meaning over restricting areas with no archaeological significance.
For these questions to be answered, it is necessary that more future research is targeted at building better case studies and an evidence base with which these ideas can be tested. It is hoped that this paper has described some of the potential between archaeology and precision farming and promoted the discussion of these ideas across many archaeological communities. We wish to thank the many people who have contributed time and advice to this research from the farming community, the precision farming industry and Historic England.