Origin and modal petrography of Luna 24 soils

Abstract

We have analyzed 6 Luna 24 soils for major and trace elements by We have performed detailed petrographic modal analyses of polished grain mounts of four sieve fractions in the size range of 20 μm to 250 μm for each of the following samples from Mare Crisium regolith: 24077,9; 24109,13; 24149,15; 24174,10; 24182,15; 24210,9. We have examined optically 7383 photographically documented soil particles. Additionally. we have made about 900 electron-probe microanalyses of the monomineralic and homogeneous glass particles. As the returned Luna 24 sample contains no large rock fragments. it is particularly important to infer the nature of the parent or source rocks from the core soil samples. Based on the regolith particle types. their relative abundances, and their chemical compositions, we have attempted to deduce the nature of source rocks for this regolith. We also attempt to estimate the relative contributions of the major source rocks.