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Title: Isotopic studies of rare gases in terrestrial samples and natural nucleosynthesis

Technical Report ·
DOI:https://doi.org/10.2172/6160941· OSTI ID:6160941

This project is concerned with research in rare gas mass spectrometry. Using a two-pronged attack, we study fluids using a system (RARGA) designed for fluid analysis in bulk which is sometimes deployed in the field and a laser microprobe mass spectrometer for fluid inclusion studies. In 1991 the RARGA project continued monitoring helium isotope variations associated with renewed seismic activity in Long Valley Caldera and expanded our geothermal data base to include Lassen National Park. An important objective, continuing in 1992, is to understand better the reasons for somewhat elevated {sup 3}He/{sup 4}He ratios in regions where there is no contemporary volcanism which could produce the effect by addition of mantle helium. To this end, 1991 saw continued efforts to understand variations in composition between fluids and associated reservoir rocks and extended the data base to include fluids from the Gulf of Mexico. Our DOE work in calibrating a sensitive laser microprobe mass spectrometer for noble gases in fluid inclusions continues with successful returns particularly in calibrating neutron irradiated samples for tracing halogen ratios. In connection with observations of neutron-produced noble gas nuclides in granites, we have begun comparing measurements with calculations for both thermal and epithermal neutrons. We submitted a third paper on noble gases in diamonds, concentrating on observed effects of {sup 4}He, {sup 3}He, and fission xenon implantation from nuclear processes in adjacent material in the matrix rock. 16 refs., 1 tab.

Research Organization:
California Univ., Berkeley, CA (United States). Dept. of Physics
Sponsoring Organization:
USDOE; USDOE, Washington, DC (United States)
DOE Contract Number:
FG03-87ER13667
OSTI ID:
6160941
Report Number(s):
DOE/ER/13667-T4; ON: DE92003468
Country of Publication:
United States
Language:
English