Abstract:

Lunar pyroclastic deposits (LPDs) originating from the explosive volcanism represent the deeper materials than the basalts in mare; they are the prior target for the lunar exploration. Reflectance spectroscopy is an important tool to study LPDs. We studied the spectrum of 29 LPDs which have been identified previously，established the distinguishing indicator of volcanic glass and proposed a new idea to compare the relative contents of FeO and TiO2 among the glassrich LPDs. The result shows that Sulpicius Gallus， Gauss，Walther A，Birt E and Aristarchus are glassrich LPDs. The titanium contents of Aristarchus, Sulpicius Gallus and Birt E are lower than those of Walther A and Gauss. The Birt E has the shallower absorption depth, and the left shoulder moves to shorter wavelength at 1 μm band. It may be caused by the very low Fe2+ content of Birt E or by its more mature material.

Key words: lunar, pyroclastic deposits, glass, M3, reflectance spectrum