Abstract:
With the development of accelerator mass spectrometry, a variety of long-lived cosmogenic nuclides, especially the
in-situ cosmogenic nuclides
10Be and
26Al, are increasingly applied to earth sciences. Based on published procedures, a modified procedure for
10Be and
26Al exposure dating has been developed, which includes
10Be and
26Al extraction, anion exchange column separation, purification and target preparation. In this procedure, NCS
9Be was chosen instead of Merck and Fluka as the carrier for the
10Be sample, with a small amount of ion exchange resin instead of a large one. In particular, the elution curve for an anion exchange column procedure by Purdue University was modified as 0.05 mol/L H
2C
2O
4-0.75 mol/L HCl to elute Al. The results of Accelerator Mass Spectrometry (AMS) show that the average for
10Be/
9Be and
26Al/
27Al of thirteen chemical blanks were 7.48×10
-15 and 1.96×10
-15, respectively, as low as those of other AMS laboratories. The ICP-AES results indicated the recoveries of Be and Al were 90% and 60%, respectively. One sample from Jinfosi Site, North of Qilian Shan Mountain, was tested based on this new procedure. The dating results of (10.7±1.0) ka for
10Be and (10.0±1.2) ka for
26Al, were consistent with published geological results.