KRYPTON-81 DATING IN POLAR ICE SAMPLES

AIR BUBBLES TRAPPED IN POLAR ICE AT THE TIME OF ICE FORMATION PROVIDE VALUABLE CLUES TO AID IN OUR UNDERSTANDINGOF THE CAUSES OF GLOBAL CLIMATE CHANGE. IT IS VITAL IN THISEFFORT THAT THE AGE OF THE ICE (WHICH MAY BE 500,000 YRS. ORMORE IN SOME LOCATIONS) BE ESTABLISHED. PRESENTLY, THERE ISNO METHOD FOR DATING ICE ABSOLUTELY BEYOND 50,000 YRS. A NEW METHOD FOR DATING POLAR ICE IN THE RANGE OF 50,000 YRS. TO 1,000,000 YRS. IS PROPOSED, BASED ON THE DIRECT MEASUREMENTS OF COSMOGENIC (81)KR (HALF-LIFE = 210,000 YRS.)IN THE TRAPPED AIR. THE METHOD CONSISTS OF ISOTOPIC ENRICHMENT OF THE KRYPTON EXTRACTED FROM THE ICE FOLLOWED BY ULTRASENSITIVE DETECTION OF THE (81)KR USING THE LASER-BASED TECHNIQUE OF RESONANCE IONIZATION SPECTROSCOPY. FEASIBILITY OF THE (81)KR TECHNIQUE WILL BE DEMONSTRATED BY MEASURING (81)KR IN TWO OLD ICE SAMPLES AND TWO MODERN ICE SAMPLES COLLECTED FROM THE ALLAN HILLS AREA OF ANTARCTICA. THE RESULTS WILL PROVIDE THE BASIS FOR DEVELOPMENT OF A COMMERCIAL (81)KR-DATING FACILITY WHICH WILL HAVE IMPORTANT APPLICATIONS, IN ADDITION TO POLAR ICE DATING, IN GROUNDWATER DATING, HYDROLOGY, SOLAR NEUTRINO STUDIES, AND METEORITE STUDIES.