Temper elemental concentrations

When the results of the yellow limestone clay and the red field clay analyses were processed by the potstat routine (10), an average of data from the two clays yielded a pattern that matched (except for sodium) the analytical pattern of pottery made of a mix of the two clays. In the first case, the two raw clays were simply ground and analyzed separately in the second case, the two clays were mixed in a water bath, sand and Dead Sea salt were added, a vessel was formed, dried, and fired, and this finished product was analyzed. The sand temper did not contribute significantly to the relative test element concentrations, but the salt addition did, of course, raise the sodium concentration. These results are graphed in Figure 2. 

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. 

Hypothetical ceramic paste mixtures are generated from clays and tempers of known concentrations by calculating elemental concentrations according to... 

Coefficients of the elemental concentrations on the first principal component (Table II) show the pattern expected for a temper-related dimension the signs are positive for all variables except K and Ba, which are negative. Thus, the group separation on principal component No. 1 shown in Figure 6 can be interpreted as temper-related. As expected, the two major groups evident on the plot are (I) hypothetical fine-paste mixtures along with raw clay and (2) hypothetical medium-paste mixtures along with real sherds. 

Ferrophosphoms is produced as a by-product in the electrothermal manufacture of elemental phosphoms, in which iron is present as an impurity in the phosphate rock raw material. The commercial product contains ca 23—29% P and is composed primarily of Fe2P [1310-43-6] and Fe P [12023-53-9] along with impurities such as Cr and V. Ferrophosphoms is used in metallurgical processes for the addition of phosphoms content. Low concentrations (up to - 0.1%) of phosphoms in wrought and cast iron and steel not only increases the strength, hardness, and wear resistance but also improves the flow properties. In large stmctural members and plates, it is desirable to use a type of steel that does not need to be quenched or tempered, and thus does not exhibit weld-hardening. This property is afforded by the incorporation of a small quantity of phosphoms in steel. Ferrophosphoms from western U.S. phosphoms production is used as a raw material for the recovery of vanadium (see Vanadiumand vanadiumalloys). 

Temper may affect the Sc/Fe ratios if the material used contains these elements in high concentrations and in a ratio much different from the clay. The three sands tested however showed nearly the same Sc/Fe correlation as the red field clays in the region where they were obtained. 

In the trace-element data, the first principal component accounts for over 50% of the variance. Aluminum and most other elements correlate positively with the first principal component, a pattern consistent with simple dilution (22,23) - in this case, by quartz sand temper. In contrast, the second principal component (accounting for an additional 15% of the variance) represents the heavy mineral sand component (Ti, Hf, Zr), which negatively covaries with cobalt, manganese, antimony, and arsenic. The Qo and Qm clays from the lowlands are broadly similar in composition (Figure 5). The Qc deposit differs significantly, i.e., the low PC2 scores indicate high concentrations of the characteristic of heavy mineral sands (Ti, Hf, Zr). The Qk and Tp samples span range of composition, but are represented by only 2 samples each. 

Early potters selected materials that were rich in clay, but in some cases, they separated coarser components from the sediments. In other cases, they added temper. In Chapter 4, Bishop and Neff discuss the effect of temper on the chemical analysis of pottery. They point out that the concentration of an element measured in a ceramic artifact can be represented mathematically. Bishop and Neff show that the analysis of pottery sherds... 

The scallop Adamussium colbecki was sampled from areas adjacent to Terra Nova Bay and Swoya research stations as well as from the Explorers Cove site which is hydrographically isolated from the influence of activities at the McMurdo Base (73). The study aimed at developing a circumpolar baseline for this species as regards trace elements in relation to the different habitat conditions. Determinations of Cd, Cu, Fe, Mn, Ni, Pb and Zn were performed on all tissues combined. The concentrations found were generally lower than those for temperate and tropical scallop species. 

This study has confirmed that soils, especially not highly evolved soils, as they are typical for mountainous areas under temperate climatic conditions, are a good mirror of the total chemical characteristics of the parent rock. However, this is only strictly true for the B- and C-horizons whieh contain little organic material. The organic top horizons often turned out to be influenced by atmospheric input, certainly often of anthropogenic origin. The solid soil phases usually concentrate most trace elements together with less soluble major elements such as Fe, Al and Si. They do this more or less in the proportions pre.sent in the parent rock. 

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