K/Ar dating of lunar soils. IV - Orange glass from 74220 and agglutinates from 14259 and 14163Total fusion Ar-40 - A-39 analyses of orange glass from lunar soil 74220 combined with the sums of earlier stepwise heating data by other workers have yielded a precise K/Ar isochron with a slope corresponding to an age of 3.66 + or - 0.03 G.y. for the orange glass. The result is in marginal agreement with Huneke's (1978) age of 3.60 + or - 0.04 G.y. for 74220 glass. The Ar systematics in the agglutinates from 14259 and 14163 are dominated by volume correlated argon. Step-wise heating analyses yield data which define experimentally reproducible linear arrays in Ar-40/Ar-36 vs. K-40/Ar-36 diagrams. The slopes of these arrays correspond formally to very old ages, but it is not clear, however, that such ages have any physical significance.
Document ID
19820038809
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Alexander, E. C., Jr. (Minnesota Univ. Minneapolis, MN, United States)
Coscio, M. R., Jr. (Minnesota Univ. Minneapolis, MN, United States)
Dragon, J. C. (Minnesota Univ. Minneapolis, MN, United States)
Saito, K. (Minnesota, University Minneapolis, MN, United States)