HOMOGENEOUS MAGNETIC-SUSCEPTIBILITIES OF TEKTITES - IMPLICATIONS FOR EXTREME HOMOGENIZATION OF SOURCE MATERIAL

Low field magnetic susceptibility of 151 tektites from the Australasia n strewn field is dominated by paramagnetism of the silicate glass. Fe rromagnetic contributions are negligible because the formation of oxid es was suppressed during rapid quenching. A few samples from the Centr al European strewn field show similar properties. Also, susceptibiliti es calculated from the large number of published geochemical analyses yield similar low susceptibilities. To produce low mass susceptibiliti es in such a narrow range of 50-100 x 10(-9) m(3) kg(-1), paramagnetic behaviour and negligible remanence, a target source that is both appr opriate and widespread over the Earth's surface is required. Modern ma rine sediments would appear to fill these requirements. The uniformity of the material, and hence its magnetic properties would be enhanced by the thorough mixing of molten terrestrial sedimentary during vapori zation and ejection and its subsequent rapid quenching. (C) 1998 Elsev ier Science B.V. All rights reserved.