Rapid Changes in the Fluoride to Chlorinity Ratio south of Greenland

Abstract

IN the early 1960s, Greenhalgh and Riley^1–3 observed anomalously high concentrations of fluoride in deep waters at several locations. The anomalies were typified by marked increases in the fluoride to chlorinity ratio at depths below 2,000 m, with some values as high as 9.0 × 10⁻⁵ g F (kg ‰Cl)⁻¹. The normal ratio in ocean water found by them, 6.7 × 10⁻⁵ g F (kg ‰ Cl)⁻¹, has since been confirmed^4–8. Eleven of the anomalous stations were in an area off southern Greenland and their occurrence seemed to be consistent with the deep circulation of the region^5,9. Greenhalgh and Riley² suggested that the anomalous fluoride concentrations in this area might be associated with mineral dissolution or submarine volcanic activity. In this communication we present additional data on fluoride at six locations south of Greenland (Fig. 1) obtained approximately 10 yr after the original observations.