Near-infrared reflectance spectra of Triton obtained from earth since 1978 shows several absorption bands between 0.8 and 4 &mgr;m, features attributed to CH4 and N2 and inferred to respect materials in the condensed state (Cruikshank and Brown, 1986, and Spencer et al., 1990) Clark et al (1983) had previously proposed a frost grain metamorphism model for icy satellite surfaces, according to which freshly condensed CH4 and N2 crystals would rapidly reconfigure themselves into a glaze or grow to unusually large sizes under the pressure and temperature conditions prevailing on Triton. In either case, the long path lengths apparently needed to explain the prominence of the absorptions could be provided. More recently, the Voyager 2 flyby of Triton revealed the existence of topographically smooth frozen ''lava lake'' and active geyserlike plumes. The presence of the former, and the solid-state greenhouse mechanism proposed by Smith et al. (1989) and Brown et al. (1990) to power the latter, both suggest the likely existence, at least as localized patches, or surficial clear ice. Thus smooth, even glazed areas of N2 and CH4 ice might occur on Triton. We report the results of a search, at the pixel scale, for such glazed areas in Voyager 2 high-resolution images of Triton. Glazed surfaces if present, are expected to produce a surge in reflectance when viewed under the geometry of specular reflection (Middleton and Mungall, 1952).

Atmosphere-insensitive green and clear filter images acquired at phase angles ranging from 60¿ to 100¿, and containing mirror points occurring over three different types of terrains (the South Polar Cap Mottled Unit, the South Polar Cap Bright Fringe, and the ''Frost Band'' region), have been surveyed. No smooth, glazed surfaces produced detectable specular reflection were found. The lack of evidence for glazed areas in the southern mid-latitude regions, at least at the scale of the spatial resolution (~3--7 km per line pair), indicates that another cause may be responsible for the prominence of Triton's spectral features. We note that the southern high-latitude regions in which active geyserlike plumes are located were not viewed under large enough incidence angles by Voyager 2 to allow conclusive searches for specular behavior. ¿American Geophysical Union 1991