Sediments pottery composition

THE USE OF FIRE TO transform CLAY PASTE into solid ceramic vessels may have been one of the earliest efforts at chemistry. Since the earliest times, pottery has been made by using clays formed by the weathering of rocks. Sedimentary deposits containing clay minerals also contain fragments of other minerals that are broken from the source rocks as they weather. The chemical composition of the sediments used as a clay source determined some of the characteristics of the pottery that was produced. 

One of the more obvious examples of this interaction involves the addition of temper to a clay matrix (temper may be another clay, but is more often a nonplastic material). The effect of tempering varies a relatively pure material, such as quartz, may reduce elemental concentrations in a ceramic paste by a constant proportion (49). Addition of other kinds of temper or clay will result in a complex relationship of dilution and enrichment (14, 25, 50). Because elemental concentrations in sediments vary depending upon grain size (e.g., references 51-53), the size distributions of the added nonplastics also contribute to compositional complexity. If behavioral inferences are to be drawn, the culturally induced elemental variation arising from texture and temper differences among pottery produced from a single clay resource requires more than simple grouping and summary statistics. 

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