USGS Astrogeology: Lunar Pyroclastic Volcanism Project

Lunar Pyroclastic Volcanism Project

Lisa R. Gaddis, U.S. Geological Survey, Flagstaff, AZ

IMAGES

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Images

Large pyroclastic deposit at Rima Bode (-3W, 13N), central lunar near side. Lunar Orbiter IV high resolution photo 109-H2.

Small pyroclastic deposits in the north and south portions of the floor of Atlas crater (Dia = 67 km; 47N, 45E). Clementine 750-nm (albedo) data.

A large pyroclastic deposit on the Aristarchus Plateau (18N-32N, 42W-57W). Clementine color-ratio composite (~500 images) in three spectral bands from the UVVIS camera: 750/415-nm ratio controls the red, the 750/1000-nm ratio controls the green, and the 415/750-nm ratio controls the blue (McEwen et al., 1994). Aristarchus, the large bright crater at lower right, is 42 km in diameter. The sinuous rille, Valles Schroteri, is also prominent on this plateau; such rilles and their "cobra-head" craters are thought to have been source vents for some pyroclastic deposits. Planetary Photojournal image PIA00090.

A small pyroclastic deposit in the eastern floor of J. Herschel crater (62N, 42W; 165 km dia.). This deposit is one of the more unusual of the small lunar pyroclastic deposits in that it appears to contain olivine as a major juvenile volcanic component (see also McCord et al., 1981).

A ring-shaped or annular pyroclastic deposit on the southern portion of the Orientale basin rim (30S, 97W). Note the central irregular depression, the probable source vent for this deposit. Clementine 750-nm (albedo) image. See also Bussey and Spudis (1996?), Head et al. (1997), and Weitz et al. (1998) for discussion of this deposit.

Examples of three types of small pyroclastic deposits on the Moon. Included (from top, left to right) are Atlas, Franklin, Eastern Mare Frigoris, and J. Herschel. The annular ring deposit at Orientale is also included for comparison. Clementine albedo (750-nm) data.

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