Soapstone analysis

To show that REE and other trace elements could be used to characterize soapstone formations, it was necessary to show that variations between geologic bodies were greater than those for soapstone samples found within the formation. For these studies instrumental neutron activation analysis (INAA) was used because of its sensitivity and preci-... 

Table I. Instrumental Neutron Activation Analysis of Soapstone Artifacts...

Count set 1 was 4-10 days and count set 2 was 30-40 days after the irradiation. Concentrations in a soapstone plummet from Labrador along with the uncertainty in the analysis arse based upon counting statistics. 

Table II. Petrographic Analysis of Thin Sections from Soapstone...

The other sample of particular interest was a spindle whorl from what is considered to be a Viking settlement at L anse aux Meadows in Newfoundland (16), A small (20 mg) sample of this unique artifact was provided by Parks Canada. After duplicate analysis of 10-mg samples, the material could be returned to Canada for further testing since INAA is a nondestructive technique. As can be seen in Figure 13, the spindle whorl has a very similar REE distribution pattern to a sample of soapstone collected from an outcrop about a mile from the habitation site (17). 

While some caution must still be used in interpreting how closely samples must match, it is clear that analysis of the REE in soapstone can be used to obtain new information about the utilization of lithic resources. The reasons that this group of elements can identify the source of soapstone are geochemical. Soapstone is a relatively rare lithic resource formed by fairly complex metamorphic processes which leave a "fingerprint in terms of the trace element content. The distribution of material with this "fingerprint will help archaeologists to imderstand the process and pattern patterns of resource procurement. However, the examples discussed above show that it is also important to know age of the artifacts to interpret the geographical distribution patterns. 

Use of Rare Earth Element Analysis to Study the Utilization and Procurement of Soapstone Along the Labrador Coast... 

Neutron activation analysis provides the necessary sensitivity and accuracy to measure rare earth element (REE) concentrations in soapstone even when geochemical processes have left the soapstone very depleted in trace elements. 

The types of variation in REE concentrations expected from a single geological source were studied at the Fleur de Lys quarry in Newfoundland. Although the absolute concentrations varied, the chondrite-normalized distribution patterns remained parallel. Analysis of debitage indicates that most materials worked were from nearby outcrops, but there was some working of soapstone from more distant quarries. Artifacts representing various Eskimo and Indian cultures over the past 4000 years have been analyzed and many have been matched to geological outcrops on the basis of their REE patterns. 

The matching of outcrop samples with debitage and other artifactual material is an ideal problem for computer-assisted pattern recognition techniques (8). The use of ARTHUR for the analysis of the soapstone from Labrador will be discussed in a future publication, but the important parameters for comparing soapstone are given in Table II. For this table, the samples from a given quarry were taken as one or two groups. The... 

Allen, R., H. Hamroush, C. Nagle, and W. Fitzhugh. 1984. Use of rare earth element analysis to study the utilization and provenance of soapstone along the Labrador Coast. In Archaeological Chemistry III, J.P. Lambert (ed.), pp. 3-18. Washington, D.C. American Chemical Society. 

Based on the EDX and SEM data, it can be inferred that the higher magnesium and/or iron content of SS 2 is related to its slightly increased resistance to an acid attack. Despite the fact that solubility analysis of the crystalline compounds was not performed here, the results are in agreement with those previously reported [7] for a study involving the investigation of cookware made of soapstone. 

Soapstone fragments found in an old trade centre of the Vikings in northern Germany were analyzed by spark source mass spectrometry. A cluster analysis of the data showed five distinct populations. A comparison... 

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