Geology of Hadley Rille preliminary report

A volcanic origin for the outflow channels of Mars: Key evidence and major implications

“…(C) The head depression (arrow) of the 1200-kmlong Venusian outflow channel Kallistos Vallis; the channel continues southward from this depression, ultimately forming complex anastamosing reaches with widths of~30 km (Baker et al, 1992b) (e.g., Lingenfelter et al, 1968;Jones and Pickering, 2003;Waltham et al, 2008), volcanic interpretations are widely favored on the basis of the availability of relevant terrestrial analogs (e.g., Greeley, 1971aGreeley, ,b, 1977, the strong association of Venusian and lunar systems with volcanic landscapes (e.g., Wilhelms, 1987;Baker et al, 1992b), the anhydrous nature of associated geological materials (e.g., Goles et al, 1970;Keil et al, 1970;Swann et al, 1972;Papike et al, 1991;Nimmo and McKenzie, 1998), and the long-term instability of water at the surfaces of Venus and the Moon (Wilhelms, 1987;Papike et al, 1991). The properties of Rima Hadley, a lunar channel visited by astronauts during the Apollo 15 mission, are consistent with its development as a conduit for lavas of mafic composition (Greeley, 1971a;Howard et al, 1972;Swann et al, 1972;Carr, 1974). Eruption rates in excess of 1 × 10 4 to 1 × 10 6 m 3 /s are estimated to have been involved in the development of lunar channels and emplacement of mare flows (e.g., Schaber, 1973;Schaber et al, 1976), and corresponding eruption rates of up to~5 × 10 7 m 3 /s have been estimated for development of the largest Venusian channels .…”

“…Flow along this reach was northward across the central part of the depicted region. 1969; Greeley, 1971a,b;Howard et al, 1972;M'Gonigle and Schleicher, 1972;Gornitz, 1973;Young et al, 1973;Schultz, 1976;Greeley and Spudis, 1978;Wilson, 1991, 1992;Leverington and Maxwell, 2004;Leverington, 2006). With channel widths of up tõ 10 km, the largest lunar outflow systems are located in the Aristarchus region of the Moon, and include Vallis Schröteri, Rimae Aristarchus, and Rimae Prinz (e.g., Gornitz, 1973;Schultz, 1976;Strain and El-Baz, 1977;Zisk et al, 1977;Wilhelms, 1987;Campbell et al, 2008) (Fig.…”

“…4A). Most lunar systems are comprised of simple channels, but some possess attributes that on other solar system bodies might be considered diagnostic of the flow of water, such as inner channels, anastamosing reaches, streamlined erosional residuals, branching channel patterns, and reaches suggestive of lateral or vertical erosion (e.g., Howard et al, 1972;Gornitz, 1973;Carr, 1974;Schultz, 1976;Strain and El-Baz, 1977;Greeley and Spudis, 1978;Wilhelms, 1987;Leverington, 2004Leverington, , 2006Bleacher et al, 2010). The morphologies of lunar channels and numerous mare flows suggest that associated lavas were generally erupted with low yield strengths and at high flow rates (Hulme, 1973;Schaber, 1973;Hulme, 1974;Guest and Murray, 1976;Head, 1976;Schaber et al, 1976;Hulme and Fielder, 1977;Gifford and El-Baz, 1981;Hulme, 1982;Wilson, 1991, 1992;Zimbelman, 1998), and such inferences are consistent with the high iron and titanium contents and low silica content typical of lunar magmas McBirney, 1970, 1973).…”

A laser-ablation ICP-MS study of Apollo 15 low-titanium olivine-normative and quartz-normative mare basalts

“…These features are evident from dark-mantled deposits and terraces along the Apennine front (Ryder, 1989), the massive Hadley Rille lava tube (Howard et al, 1972), and the consistency in mare basalt regolith compositions (<1.5 wt. % TiO 2 ) at the Apollo 15 site (Blewett and Hawke, 2001).…”

On the structure of mare basalt lava flows from textural analysis of the LaPaz Icefield and Northwest Africa 032 lunar meteorites

“…Pyroxene compositions and whole-rock REE data are from Day et al (2006b), andFagan et al (2002;. The flow thickness estimate is based on cooling rate-flow thickness relations of Grove and Walker (1977), and the thickness of mare basalt flows imaged from Hadley Rille (Howard et al 1972).…”