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R.S. Saunders

Publications and source records attributed to R.S. Saunders.

7 recordsLinked to original sources

Rocky 7 prototype Mars rover field geology experiments: 1. Lavic Lake and Sunshine volcanic field, California

Experiments with the Rocky 7 rover were performed in the Mojave Desert to better understand how to conduct rover-based, long-distance (kilometers) geological traverses on Mars. The rover was equipped with stereo imaging systems for remote sensing science and hazard avoidance and 57 Fe Mössbauer and nuclear magnetic resonance spectrometers for in situ determination of mineralogy of unprepared rock and soil surfaces. Laboratory data were also obtained using the spectrometers and an X ray diffraction (XRD)/XRF instrument for unprepared samples collected from the rover sites. Simulated orbital and descent image data assembled for the test sites were found to be critical for assessing the geologic setting, formulating hypotheses to be tested with rover observations, planning traverses, locating the rover, and providing a regional context for interpretation of rover-based observations. Analyses of remote sensing and in situ observations acquired by the rover confirmed inferences made from orbital and simulated descent images that the Sunshine Volcanic Field is composed of basalt flows. Rover data confirmed the idea that Lavic Lake is a recharge playa and that an alluvial fan composed of sediments with felsic compositions has prograded onto the playa. Rover-based discoveries include the inference that the basalt flows are mantled with aeolian sediment and covered with a dense pavement of varnished basalt cobbles. Results demonstrate that the combination of rover remote sensing and in situ analytical observations will significantly increase our understanding of Mars and provide key connecting links between orbital and descent data and analyses of returned samples.

Journal of Geophysical Research E: Planets

Venus volcanism: Initial analysis from Magellan data

Magellan images confirm that volcanism is widespread and has been fundamentally important in the formation and evolution of the crust of Venus. High-resolution imaging data reveal evidence for intrusion (dike formation and cryptodomes) and extrusion (a wide range of lava flows). Also observed are thousands of small shield volcanoes, larger edifices up to several hundred kilometers in diameter, massive outpourings of lavas, and local pyroclastic deposits. Although most features are consistent with basaltic compositions, a number of large pancake-like domes are morphologically similar to rhyolite-dacite domes on Earth. Flows and sinuous channels with lengths of many hundreds of kilometers suggest that extremely high effusion rates or very fluid magmas (perhaps komatiites) may be present. Volcanism is evident in various tectonic settings (coronae, linear extensional and compressional zones, mountain belts, upland rises, highland plateaus, and tesserae). Volcanic resurfacing rates appear to be low (less than 2 km 3 /yr) but the significance of dike formation and intrusions, and the mode of crustal formation and loss remain to be established.

Science

Shuttle imaging radar experiment

The shuttle imaging radar (SIR-A) acquired images of a variety of the earth's geologic areas covering about 10 million square kilometers. Structural and geomorphic features such as faults, folds, outcrops, and dunes are clearly visible in both tropical and arid regions. The combination of SIR-A and Seasat images provides additional information about the surface physical properties: topography and roughness. Ocean features were also observed, including large internal waves in the Andaman Sea.

Andaman Sea, Indian Ocean

Geologic map of the Margaritifer Sinus Quadrangle of Mars

The Margaritifer Sinus quadrangle lies within a broad north-sloping trough, the Chryse lowlands, between the elevated Tharsis plateau to the west and the cratered upland to the east. The rugged, uniquely martian chaotic terrain is best developed in this quadrangle. Sinuous furrows a few kilometers wide and as much as several hundred kilometers long cover most of the quadrangle; in several places are broad regions many tens of kilometers wide that appear to be complex channel systems. None of these features can be correlated with markings seen from the Earth. The major part of the quadrangle consists of moderately cratered material containing craters of different morphologic types. This region is typical of the most cratered region of Mars (Jones, 1974), have been previously mapped as cratered terrain, undivided (Carr and others, 1973), as moderately cratered terrain (McCauley and others, 1972), and as plateau plains (Wilhelms, 1974).

IMAP

Geologic map of the Hommel quadrangle of the Moon

The Hommel quadrangle is in the southeas t highlands of the earthside hemisphere of the Moon. The major geologic units are smooth and ridged terra materials, plains-forming materials, and crater materials. Mare material is absent. In the absence of extensive stratigraphic datum horizons, the geologic units were tentatively correlated with type areas of the lunar geologic system (Shoemaker and Hackman, 1962; Wilhelms , 1970) by means of a graded sequence of crater morphologies.

IMAP