Neutron Activation Analysis of Selected Conodonts
Conodont samples were irradiated at the Air Force Nuclear Test Center, Dayton, Ohio, over a period of approximately thirteen months. Changes in the times of irradiation and the times of reading of the samples were made to determine consistency of data, procedure, and elemental composition.
The conodont samples were selected on the following criteria: morphological features, such as lamellar structure contrasted with fibrous structure, environmental differences, such as shelf conditions contrasted with geo-synclinal conditions and presence or absence of basal material. It was postulated that irradiation and subsequent analysis of trace-element composition might indicate differences in the above groups. The basic data from the neutron activation analysis were interpreted manually and also computerized to produce a cluster analysis in the form of a dendrogram.
The neutron activation analysis of samples repeated four different times over a span of 13 months produced consistent data. Differences in isotopic content between lamellar and fibrous conodonts are suggested by the dendrogram. Differences in isotopic content exist between conodonts with and without basal material, but these differences appear inconsistent at present. Differentiation of faunas on the basis of environmental differences was not conclusive.