Anomalous Carbon-Isotope Ratios in Nonvolatile Organic Material

Abstract

Organic mats are associated with sulfur deposits in Upper Pleistocene sand ridges of the coastal plain of southern Israel; black, brittle, and non-volatile, they show parallel layering but no other apparent cellular structure. Two independent carbon-14 determinations yielded ages of 27,750±500 and 31,370±1400 years. Four carbon-13:carbon-12 determinations fell within the range δC¹³ =-82.5 to -89.3 per mille relative to the PDB standard; these appear to be the lowest values yet reported for naturally occurring high-molecular-weight organic material. The origin of the carbon is probably complex; it must have passed through at least one biologic cycle before final deposition.