Capabilities of the Lamont-Doherty Earth Observatory in situ 14C extraction laboratory updated

We report on the status and capabilities of the Lamont-Doherty Earth Observatory in situ C-14 extraction laboratory. In late 2006 we began, in collaboration with the AMS group at the University of Arizona, construction of a new laboratory to extract in situ cosmogenic C-14 from terrestrial silicates. Long-term measurements of the process blank over the last two years give an arithmetic mean and standard deviation of 125 +/- 43 x 10(3) atoms C-14 (n = 9) and show significant improvement in the number of atoms, as well as stability compared to initial measurements of the process blank. We report long-term measurements of the intercomparison material CRONUS-A, which has been developed as part of the CRONUS-Earth effort to characterize inter- and intra-laboratory variability. We interpret the standard deviation (5%) of six replicate measurements of CRONUS-A as the reproducibility of in situ C-14 extractions in our laboratory. Published by Elsevier B.V.