Strontium isotope measurements in Greenland ice from the last glacial maximum to the early Holocene

Abstract

Strontium isotopic composition and concentration have been measured by thermal ionisation mass spectrometry on a suite of samples from the GRIP ice core drilled at Summit, Greenland. The sample ages range from similar to24 to similar to7.3 ky BP extending from the last glacial maximum into the early Holocene. Less than 10 g of sample was used for each analysis. No attempt was made to separate soluble/insoluble species in the samples. Sr concentrations are between similar to950 and similar to1,550 pg.g(-1) over the period similar to24 ky to similar to14 ky BP but fall dramatically to generally less than 150 pg.g(-1) between similar to14 to similar to7.3 ky BP. The Sr-87/Sr-86 ratio shows a general rising trend from similar to0.712 to similar to0.715 over the entire period however there are a number of significant deviations from this trend which are most likely due to changing source regions for aerosol dust input to Greenland. Sr isotopic composition shows a strong correlation with delta(18)O suggesting that climate plays a strong role in determining regions for dust release.