| Abstract: | Abstract— A preliminary investigation into the carbon isotopic composition of deep-sea spherules has been undertaken. A variety of particles have been analysed including both melted and unmelted samples of type S (stony) and type I (iron) spherules, emphasis being placed on surveying the carbon in different sorts of particles rather than analysing large numbers of samples. Some general observations can be made: there appear to be four different sorts of carbonaceous materials in the spherules. Melted and unmelted spherules of either type I or S, apparently contain two forms of low temperature combustible carbon distinguished, not by combustion temperature, but by isotopic composition. The low temperature of combustion is commensurate with these forms of carbon being organic in nature. The most likely explanation for this carbon is terrestrial biogenic contamination although there exists the possibility that there are some indigenous organic materials. Unmelted type S spherules contain a high temperature carbon component, characterised by a very minor 13C-enrichment, which is considered to be indigenous to the sample. All melted samples contain only small amounts of high temperature carbon with an isotopic composition suggestive of handling blank. |
