THE NATURAL THERMOLUMINESCENCE OF METEORITES VI - C-14, THERMOLUMINESCENCE AND THE TERRESTRIAL AGES OF METEORITES

Research on meteorite finds, especially those from the Antarctic and f rom desert regions in Australia, Africa, and America, has become incre asingly important, notably in studies of possible changes in the natur e of the meteorite flux in the past. One important piece of informatio n needed in the study of such meteorites is their terrestrial age whic h can be determined using a variety of methods, including C-14, Cl-36, and Kr-81. Natural thermoluminescence (TL) levels in meteorites can a lso be used as an indicator of terrestrial age. In this paper, we comp are C-14-determined terrestrial ages with natural TL levels in finds f rom the Prairie States (central United States), a group of rinds from Roosevelt County (New Mexico, USA), and a group from the Sahara Desert . We find that, in general, the natural TL data are compatible with th e C-14-derived terrestrial ages using a 20-degrees-C TL decay curve fo r the Prairie States and Roosevelt County and a 30-degrees-C decay cur ve for the Saharan meteorites. We also present TL data for a group of meteorites from the Sahara desert which has not been studied using cos mogenic radionuclides. Within these data there are distinct terrestria l age dusters which probably reflect changes in meteorite preservation efficiency over approximately 15,000 years in the region.