Chemical composition of North American microtektites and tektite fragments from Barbados and DSDP Site 612 on the continental slope off New Jersey

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We have determined the major element and trace element content of tektite fragments and microtektites found in deep-sea sediments from Barbados and DSDP Site 612 on the continental slope off New Jersey. The major element and trace element contents were determined using energy dispersive X-ray analysis and instrumental neutron activation analysis, respectively. The compositions are consistent with the conclusion that the samples from both occurrences belong to the North American tektite strewn field. The chemistry of the samples from both occurrences is, however, not identical with the bediasite or georgianite chemistry. There are differences especially in the lower sodium and higher K and Cr and possibly higher volatile element contents of the tektite fragments from DSDP Site 612. The differences in chemistry between bediasites, georgianites, and the tektites from the sites analyzed here show that there are geographical variations in composition in the North American strewn field like in the Czechoslovakian or Australasian strewn field. The relatively high volatile element contents (e.g., Sb and Au) of the Site 612 tektite fragments, together with the occurrence of mineral inclusions and a layered structure of some specimens, indicates that these specimens are (or close to) Muong-Nong-type tektites. If the DSDP Site 612 tektites are Muong-Nong type, then the source crater has to be close to that site and is therefore probably on the continental shelf as had previously been suggested. Tektites on land usually occur in deposits which are much younger than the tektites — the so-called age paradox. The association of tektites and microtektites together in one layer with a stratigraphic age that is consistent with the radiometric age would seem to resolve this paradox.