Phosphates in archaeology
History of use in archaeology
Accuracy and validity of the methodology
Performing a phosphate analysis survey
Interpretive possibilities


The ability of phosphate analysis techniques to accurately identify archaeological features, as well as less tangible components through the identification of pathways and activity areas, makes phosphate testing highly applicable to a large variety of archaeological sites.  The utilization of this information to create use-of-space models helps determine land-use patterns over sites, allows for greater trends between sites to be identified and aids in the archaeological interpretation of large- and small-scale site dynamics.  The methodology I use is particularly suited to obtaining accurate and readable results for several reasons:

          - the test only takes 2 minutes to perform on each sample.
          - the test supplies are inexpensive, and no specialist laboratory equipment is needed.
          - the test is 97% accurate for identifying anthropogenic phosphates  as a result of the phosphate.
             mineralization rate, which can be used to weed out interference from modern phosphates (phosphates
             added in the last 200-500 years depending on environmental conditions), and the strength of soil
             bonds to natural mineral phosphates, which are not released by the test.
          - modern and historic field amendments rarely interfere with the identification of anthropogenic
          - the test can identify features not often visible in the archaeological record including:
                         - buildings constructed primarily of organic material
                         - sleeping areas
                         - food consumption and storage areas
                         - craft-working areas
                         - storage areas
                         - garden areas
                         - pathways that can show how buildings and areas were accessed 
                        - entryways
                         - boundaries
          - the test can locate previously unknown archaeological sites and features, such as: 
                         - structures
                         - middens 
                         - hearths and other food production areas
                         - pits
                         - burials 
                         - animal pens
          - the test can also determine how features were used, including all of the abovementioned types of
             sites and features.
          - the test can differentiate between site uses, including full-scale sedentary occupation, episodic
             occupation, and sites not used for occupation, such as some religious/military, etc., where access
             would have been limited to specific individuals and/or at specific times.
          - the results from phosphate analysis can be used to create interpretive use-of-space models for
             site and social dynamics.

I hope this web-page will serve to inform archaeologists about the applications of phosphate analysis as an example of how the technique can be used to clarify issues of function and use on archaeological sites, and contribute to the advancement of the use of phosphate analysis in the field. 


Johanna Ullrich, Ph.D.