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Geology topics

Jim D. Gleason

Publications and source records attributed to Jim D. Gleason.

5 recordsLinked to original sources
USGS1975

Oats may grow better in water depleted in oxygen 18 and deuterium

WHILE growing oats at different temperatures in water of different 18 O and deuterium (D) abundances, we noticed that oats grown in Antarctic water in which is depleted in 18 O and D by −49‰ and −400‰, relative to standard mean ocean water (SMOW used as a comparative reference in hydrogen and oxygen isotope studies), showed initial growth 1–2 weeks sooner than did oats grown in water containing greater 18 O and D concentrations. The oats seemed to grow better in water which was most depleted in the stable isotopes throughout the growth period.

Nature↗
USGS1974

Isotopic composition of carbon and hydrogen in some Apollo 14 and 15 lunar samples

Isotopic composition of carbon and hydrogen in some Apollo 14 and 15 lunar samples was determined by use of a newly constructed combustion line that yields low blanks for CO 2 and H 2 . The results from combustion of fines and breccia from Apollo 14 lunar samples and of fines, breccia, and basalt from Apollo 15 were compared with data obtained by heating samples in vacuo to over 1,350°C. The two techniques gave similar results. Total carbon in the fines ranged from 51 to 110 p/m with a C 13 of +12 to -8 per mil (parts per thousand) PDB. The breccias contain 22 to 50p/mcarbon with a C 13 of -21 to -25 per mil. The crystalline rock (sample 15555) has a carbon content of about 7 p/m and a C 13 of -28 per mil. The total hydrogen in the fines ranges from 66 to 120 p/m with a (D/H) X 10 -6 of 39 to 90. The breccias contain 8 to 38p/mH 2 with a (D/H) X 10 -6 of 103 to 144. The crystalline rock contains about 2 p/m H 2 with a (D/H) X 10 -6 of about 140. Arguments are presented to show that the contamination by earth materials is not as serious a problem as has been proposed by previous authors.

Journal of Research of the U.S. Geological Survey↗
USGS1973

Notes on the bromine pentafluoride technique of oxygen extraction

The necessity to use a dry box when loading silicate samples into reaction vessels prior to fluorination is eliminated by the use of a simple loading technique. Data presented show the reproducibility of the fluorination reaction using this technique. Sodium fluoride, when added to saline waters prior to fluorination, improves the precision of the overall technique.

Journal of Research of the U.S. Geological Survey↗
USGS1971

Isotope fractionation during gas chromatographic separations

Physical interaction between the sample and stationary phase during GC separations may result in severe isotopic fractionation of the effluent, making it essential to collect it totally in order to obtain quantitative results. When carbon dioxide was eluted through a Porapak column the front portions of the elution peak was enriched in 13 C. When methane was eluted through molecular sieve, both the heavier species were eluted faster than the lighter ones. However, when the carbon dioxide was eluted through silica gel the first CO 2 eluted was enriched in 13 C and the last CO 2 eluted was enriched in 18 O. This behavior of the isotopes probably indicates the presence of two different interaction mechanisms.

Journal of Chromatographic Science↗