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 ∼24 to ∼7.3 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 ∼950 and ∼1,550 pg.g -1 over the period ∼24 ky to -14 ky BP but fall dramatically to generally less than 150 pg.g -1 between -14 to ∼7.3 ky BP. The 87 Sr/ 86 Sr ratio shows a general rising trend from ∼0.712 to ∼0.715 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 δ 18 O suggesting that climate plays a strong role in determining regions for dust release.