National Ocean Sciences Accelerator Mass

In order to provide AMS analyses to the broad ocean sciences research community, the National Ocean Sciences Accelerator Mass Spectrometry Facility (NOSAMS) was established at Woods Hole Oceanographic Institution (Massachusetts) in 1989. Studies performed there include identification of sources of carbon-bearing materials in the water column and sediment, dating of sedimentary samples, investigations of paleocirculation patterns (e.g., from observations of differences in 14C relative abundances in planktonic and benthic foraminifera, and coral cores and cross sections), as well as studies of modern oceanic carbon cycling and circulation. In fact, much that is known about advective and diffusive processes in the ocean comes from measurements of chemical tracers, such as 14C, rather than from direct measurements of water mass flow. 

Ann McNichol is a Research Specialist at the National Ocean Sciences Accelerator Mass Spectrometry Facility at the Woods Hole Oceanographic Institution, which produces high-precision 14C measurements from small-volume samples. Dr. McNichol s research interests include the study and use of carbon, nitrogen, and oxygen isotope techniques to quantify bio-geochemical processes, the study of the fate of organic matter (both natu-... 

The 8 C of DIC was determined by acidification and automated vacuum extraction of small samples (3-5 mL), followed by isotope ratio measurements on the VG-PRISM mass spectrometer in the National Ocean Science Accelerator Mass Spectrometer laboratory at WHOl (McCorkle et al. 1990 McCorkle Klinkhammer 1991). The standard deviation of replicate extractions and isotopic analyses was 0.04%c (2002, n = 14) 8 C values are reported relative to VPDB. 

National Ocean Sciences Accelerator Mass Spectrometry Facility and Department of Geology and Geophysics Woods Hole Oceanographic Institution Woods Hole, Massachusetts 02543... 

A multi-wire counter was used by Libby to measure the radiocarbon content in archeological artifacts. The first sample he dated was a piece of acacia wood from furniture in Pharaoh Zoser s tomb at Saqqara, Egypt. About 20 g were used, and the date determined was 2,030 350 years BC. The technique developed rapidly, and only 10 mg of the same sample were dated in 1992 in the new National Ocean Sciences Accelerator mass spectrometry facility at Woods Hole Oceanographic Institution and gave an age of 4,115 34 years, i.e., within one cr error of the first (Libby) analysis. The Oeschger Counter is another indispensable tool on... 

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