IMPROVED TECHNIQUES FOR STABLE-ISOTOPE ANALYSES OF MICROLITER QUANTITIES OF WATER FROM FLUID INCLUSIONS IN HALITE AND CONCENTRATED BRINES

A method has been developed to analyze both H- and O-isotope compositi ons of saline waters and fluid inclusion brines without significant in terference of salts. It involves high-temperature distillation under v acuum and reaction of the extracted water with zinc to produce H-2 for H-isotope analyses and with guanidine hydrochloride (GuHCl) to produc e CO2 for O-isotope analyses. Precisions of +/- 2 parts per thousand a nd +/- 0.3 parts per thousand for delta D- and delta(18)O-values, resp ectively, can be realized with as little as 4 mu l saline water for bo th elements.