USGS -- Scientific Capabilities - Geochronology, Geochemistry, and Tracer Studies



The Geologic Division maintains a variety of high quality, state-of-the-art facilities that provide geochronological, geochemical, and isotopic tracer studies applied to both natural and artificial systems. Instruments and scientific staff are housed across the country in the major centers and are variably utilized according to programmatic and project priorities. Capabilities are logically subdivided into geochronology activities and geochemical and tracer studies.


In current and future USGS research activities, the components of societal relevance, impact, and accountability place exceptional technical demands upon geochronologic and other isotopic methods presently available to GD project studies. The critical operative in these studies is the time-space framework established through careful geologic mapping, observations, and sampling (framework), coupled with isotopic tracer and geochronologic investigations. Isotopic investigations increasingly must focus on surficial processes that include global climate change, environmental impact and remediation issues, life science (ecosystem) and human health issues, early man and human evolution, volcano, earthquake, and landslide hazards assessment and monitoring, water quality and availability studies, kinetics and rate studies of surficial earth processes, ocean-atmosphere-biosphere interaction (and carbon cycle), and geochemical-hazards-resources issues related to development and expansion of urban corridors and vast agricultural lands under pressures from population growth. In common, these applications all emphasize the 'young' end of the age spectrum, extending the capabilities of conventional methods and instrumentation to Holocene and even historic time. USGS capabilities in U-series, 14C, 40Ar/39Ar, and TL dating methods are critically important and must be maintained substantially above a minimum level of competency.

In response to this need, a Quaternary Geochronology group is forming to refine and strengthen techniques applicable to the 'young' age earth science problems that include U-series, C-14, Pb-210,-Ar-Ar, TL-OSL, and noble gas geochemistry (3H/3He, 4He and 40Ar in-growth, and 3He/4He for direct age determinations, Ne/Ar/Kr/Xe molecular and isotopic ratios, 3He/21Ne surface exposure ages with phases such as olivine, pyroxene, garnet, and quartz), and 39Ar, 81Kr, and 85Kr in groundwater).




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