Differences Observed in Iron Content Be- Tween Crater Ejecta and Surrounding Mare Basalt Surfaces: Implications for Sample Remote Sensing Integration

near Taruntius Crater appears to be relatively young (~1 Ga) [14]. Of >80 floor-fractured craters mapped by Wilhelms ( Plate 5 in [15]), ~15 have pyroclastic deposits, suggesting that these features may have provided an enhanced environment for explosive volcanic eruption. The spatial association of volcanic eruption sites and impact craters and basins on the Moon is believed to be related to crustal thinning beneath impact sites. Small pyroclastic deposits are observed in regions with crustal thicknesses ranging from 30 to 80 km [2], with the majority near 50 km. On the nearside, these crustal thicknesses are typical of the margins of the major maria; on the farside, thinner crust is observed in the South Pole/Aitken Basin and the Moscoviense Basin, sites where pyroclastic deposits are observed. We are currently evaluating these data to investigate implications for modes of eruptions of lunar pyroclastic deposits. References: [1] Clementine Basemap Mosaic, 15 volumes, prepared by USGS for NASA, available via the Planetary Data System Imaging Node. [2] Zuber et al. (1994) Science, 266, 1839– 1843. [3] Gaddis et al. (1985) Icarus, 61, 461–488. [4] McEwen et al. (1994) Science, 266, 1858–1861. [5] Robinson et al. (1996) LPS XXVII, 1087–1088. [6] Head and Wilson (1979) Proc. LPSC 10th, 2861–2897. [7] Hawke et al. (1989) Proc. LPSC 19th, 255–268. [8] Shoemaker et al. (1994) Science, 266, 1851–1854. [9] Gaddis et al. (1997) LPS XXVII, 389–390; Gaddis et al. (1998) LPS XXIX; Rosanova et al. (1998) LPS XXIX. [10] Head and Wilson (1992) GCA, 56, 2155–2175. [11] Coombs and Hawke (1992) Proc. LPS, Vol. 22, 303–312. [12] Weitz et al. (1997) LPS XXVIII, 1533. [13] Schultz (1976) Moon, 241; Wichman and Schultz (1995) JGR, 100, 21201. [14] Spudis (1989) NASA TM 4210, 406–407. [15] Wilhelms (1987) USGS Prof. Paper 1348.