Matthew I. Staid James A. Tyburczy B. Ray Hawke Noah E. Petro Lisa R. Gaddis 2003 <p><span>The 5-band Clementine UVVIS data at ∼100 m/pixel were used to examine the compositions of 75 large and small lunar&nbsp;pyroclastic deposits&nbsp;(LPDs), and these were compared to representative&nbsp;lunar maria&nbsp;and highlands deposits. Results show that the&nbsp;albedo, spectral color, and inferred composition of most LPDs are similar to those of low-titanium, mature&nbsp;lunar maria. These LPDs may have consisted largely of fragmented&nbsp;basalt, with substantial components of iron-bearing mafic minerals (pyroxenes, olivine) and smaller amounts (if any) of&nbsp;volcanic glass. Several smaller LPDs also show substantial highland components. Three classes of very large deposits can be distinguished from most LPDs and from each other on the basis of&nbsp;</span>crystallinity&nbsp;<span>and possible titanium content of their pyroclastic components. One class has spectral properties that are dominated by high-titanium, crystallized “black beads” (e.g., Taurus–Littrow), a second consists of a mixture of high-titanium glasses and beads with a higher glass/bead ratio (Sulpicius Gallus) than that of Taurus–Littrow, and a third has a significant component of quenched iron-bearing volcanic glasses (Aristarchus) with possible moderate titanium contents. Although areally extensive, these three classes of very large pyroclastic deposits compose only 20 of the 75 deposits studied (∼27%), and eruption of such materials was thus likely to have been less frequent on the Moon.</span></p> application/pdf 10.1016/S0019-1035(02)00036-2 en Elsevier Compositional analyses of lunar pyroclastic deposits article