Isotopic tracing (Sr, Nd, U, and Hf) of continental and marine aerosols in an 18th century section of the Dye-3 ice core (Greenland)

Determining the sources and pathways of atmospheric mineral dust and marine aerosols remains a difficult problem. In order to address this problem, the radiogenic isotopic composition of the dust and soluble ice components of Greenland ice has been determined and used as a source tracer for mineral dust and marine aerosols. Sr and Nd isotopic composition was measured, with a yearly to seasonal resolution, on both the bulk dust and soluble fractions of a section of the Dye-3 (1988) ice core from Greenland in the age range of 1786–1793 A.D. Hf isotopic composition was also measured for three of the dust samples as a complementary tracer of dust origin, the first direct measurement of Hf in paleo-atmospheric dust. Measured Nd and Sr isotopic composition of the dust corrected for carbonate contributions are compared to literature potential source area (PSA) data (6 ε units) and are decoupled from dust composition, indicating that the Nd composition of seawater is preserved in the ice. The εNd of the ice suggests variable mixing of aerosols from Arctic sea salts with another, more radiogenic, source during transport