9730699 Donahue This grant provides an additional three years partial support of the operations and maintenance budget for the University of Arizona accelerator mass spectrometry (AMS) facility. The Arizona AMS lab has been in operation since 1981 under continuous NSF funding with the intentions of supporting the frontier in- house research and technique development conducted by the Arizona AMS staff and to provide radiocarbon (14C) dating services primarily for NSF-funded PI's. The lab presently analyzes the 14C content of over 3,500 samples per year of which about 19% were for in-house research. This facility supports the needs of not just Earth scientists, but also, oceanographers, glaciologists, hydrogeologists, archaeologists, planetary scientists and atmospheric scientists. Examples of research that have relied on Arizona AMS analyses include: paleoclimatological studies of ice sheet dynamics in Antarctica and mountain glacier dynamics in the mid-latitude Chilean Andes; studies in paleoseismology; archaeological studies of the timing of Paleoindian settlements in the Americas; atmospheric and oceanographic studies of upper water column dynamics based on the 14C/13C signatures recorded in coralline skeletons; coupled 14C and U/Th dating of corals and speleothems to extend atmospheric radiocarbon calibration beyond the present dendrochronologic limit of ca. 11.5 ka; the use of 14C as a tracer of the pools of dissolved organic and inorganic carbon pools in groundwater; and 14C investigations of the origin of carbon in chondrites and the inferred Martian meteorites. Furthermore, this lab trains a diverse array of undergraduate, graduate and post-doctoral students engaged in physics, chemistry and geoscience research programs that utilize AMS techniques. Due to the diverse range of scientific fields supported by this facility, continued NSF support is shared by the Division of Earth Sciences/Instrumentation and Facilities Program, programs within the Office of Polar Programs and the SBER/Archaeometry program. ***
