| Abstract: | Sixty-one unbroken, regularly-shaped indochinites were analyzed for potassium, rubidium, and lithium by flame emission spectrophotometry. Mass and an estimate of surface area (calculated from a specimen's dimensions) were also determined. Two compositional sub-groups were identified and designated as type N (normal) and type L (low-alkali) indochinites. For the 56 type N specimens, K, Rb, and Li were all correlated with mass, suggestive that selective volatilization occurred during the formation of indochinites. Correlations were not significantly enhanced by simultaneously considering the effects of both mass and surface area on alkali abundances via multiple regression analysis or the use of a composite independent variable. All possible pairings of K, Rb, and Li were correlated, suggestive that an imperfect mixing process may have occurred during the formation of indochinites. Hotellings t-test indicated that all inter-alkali correlations were significantly higher than any of the mass-alkali correlations. Negative correlations were found for K/Li and Rb/Li vs. Li. These trends may be attributed to 1) the fusion of a parent material that was homogeneous with respect to alkali element ratios that experienced more rapid depletion of the more volatile species of an alkali pair for those tektites with initially higher alkali contents, or 2) the imperfect mixing of a “lithium-rich” and a “lithium-poor” component. |
