Exchange of lyotropic series cations by micaceous vermiculite and its weathering products determined by electron microscopy and radiochemical analysis. Annual progress report, August 1, 1975--July 31, 1976

The problem of hydrolysis of UO22+ during the determination of surface charge of micas was eliminated by the washing with 0.01M UO2(NO3)2 of pH 2.4 and then blotting off the liquid. The replica method of determining the 235U fission tracks induced by thermal neutrons was developed to give a constant HF etching time to make the tracks visible. The replica method was also applied to the determination of the U concentration in micas and their age-dating. Diverse divalent cations in trace concentrations were found to adsorb specifically (i.e., in 1M NaNO3) on hydrous oxides of Fe and Al. The results with 90Sr2+ and 45Ca2+ were published; those with Cd, Zn, and other transition and heavy metals were submitted for publication. Insight into fixation of cations such as 137-Cs+ was provided by determination of the kinetics of the mica-vermiculite reaction in relation to partial pressure of CO2, and by high resolution electron microscopy, revealing images of interlayer wedge configurations. Aerosol size quartz had less variable oxygen isotopic ratios in eolian than fluvial systems; also, its trace element concentrations as well as isotopic ratios were useful in assigning provenance. Quartz of chert origin was revealed electron microscopically as clusters of subhedral crystals