Publications
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Energy sources for triton's geyser-like plumes Energy sources for triton's geyser-like plumes
Four geyser-like plumes were discovered near Triton's south pole in areas now in permanent sunlight. Because Triton's southern hemisphere is nearing a maximum summer solstice, insolation as a driver or a trigger for Triton's geyser-like plumes is an attractive hypothesis. Trapping of solar radiation in a translucent, low-conductivity surface layer (in a solid-state greenhouse), which is
Authors
R. H. Brown, Randolph L. Kirk, T. V. Johnson, Laurence A. Soderblom
Volcanism in Northwest Ishtar Terra, Venus Volcanism in Northwest Ishtar Terra, Venus
Soviet Venera 15/16 radar images and topographic data for an area in NW Ishtar Terra, Venus (74°N, 313°E) contain evidence for the existence of a complex volcanic center. Located at the intersection of Akna and Freyja Montes (both elevated ∼4 to 7 km above the planetary reference radius of 6051 km), this volcanic center has a complex caldera system, possibly more than one major eruptive...
Authors
Lisa R. Gaddis, Ronald Greeley
Dark materials in Valles Marineris: Indications of the style of volcanism and magmatism on Mars Dark materials in Valles Marineris: Indications of the style of volcanism and magmatism on Mars
Rifting on the equatorial canyon system of Valles Marineris provides a unique view of the interior of the Martian crust to depths reaching 7 km, exposing several in situ bedrock units which testify to past volcanic and magmatic processes on Mars. A thick, regionally extensive deposit observed in Coprates and Juventae chasmata is interpreted on the basis of spectral reflectance, erosional
Authors
Paul E. Geissler, Robert B. Singer, Baerbel K. Lucchitta
Flank tectonics of Martian volcanoes Flank tectonics of Martian volcanoes
On the flanks of Olympus Mons is a series of terraces, concentrically distributed around the caldera. Their morphology and location suggest that they could be thrust faults caused by compressional failure of the cone. In an attempt to understand the mechanism of faulting and the possible influences of the interior structure of Olympus Mons, we have constructed a numerical model for...
Authors
Paul Thomas, Steven W. Squyres, M. H. Carr
Lava flow surface textures: SIR-B radar image texture, field observations, and terrain measurements Lava flow surface textures: SIR-B radar image texture, field observations, and terrain measurements
Space Shuttle Imaging Radar (SIR-8) images, field observations, and small-scale (cm) terrain measurements are used to study lava flow surface textures related to emplacement processes of a single hawaiian lava flow. Although smooth pahoehoe textures are poorly characterized on the SIR-B data, rougher pahoehoe types and the a'a flow portion show image textures attributed to spatial...
Authors
Lisa R. Gaddis, Peter J. Mouginis-Mark, Joan N. Hayashi
Investigating climate change by digital analysis of blue-ice extent on satellite images of Antarctica Investigating climate change by digital analysis of blue-ice extent on satellite images of Antarctica
Landsat-5 Thematic Mapper (TM) and SPOT data collected two years apart from an identical area of Dronning (Queen) Maud Land, Antarctica, have been analyzed to detect variations in surface features that may signal climatic change, and to establish a technique that readily identifies such changes. We found that selective principal component analysis (Chavez and Kwarteng 1989), on band...
Authors
Olav Orheim, Baerbel K. Lucchitta
Young volcanic deposits in the Valles Marineris, Mars? Young volcanic deposits in the Valles Marineris, Mars?
A study of the interior deposits of the central Valles Marineris has led to the discovery of a sequence of deposits that cover the chasma floors and range in thickness from that of thin dust to several kilometers. The emplacement of the deposits was the last major event in the history of the Valles Marineris, following deposition of older layered interior beds, warping, faulting, erosion...
Authors
Baerbel K. Lucchitta
Voyager 2 at Neptune: Imaging science results Voyager 2 at Neptune: Imaging science results
Voyager 2 images of Neptune reveal a windy planet characterized by bright clouds of methane ice suspended in an exceptionally clear atmosphere above a lower deck of hydrogen sulfide or ammonia ices. Neptune's atmosphere is dominated by a large anticyclonic storm system that has been named the Great Dark Spot (GDS). About the same size as Earth in extent, the GDS bears both many...
Authors
B.A. Smith, Laurence A. Soderblom, D. Banfield, C. Barnet, A.T. Basilevsky, R.F. Beebe, K. Bollinger, J. M. Boyce, A. Brahic, G.A. Briggs, R. H. Brown, C. Chyba, S.A. Collins, T. Colvin, A.F. Cook, D. Crisp, S.K. Croft, D. Cruikshank, J.N. Cuzzi, G. E. Danielson, M. E. Davies, E. DeJong, L. Dones, D. Godfrey, J. Goguen, I. Grenier, V. Haemmerle, H. Hammel, C.J. Hansen, C.P. Helfenstein, C. Howell, G.E. Hunt, A.P. Ingersoll, T. V. Johnson, J. Kargel, Randolph L. Kirk, D.I. Kuehn, S. Limaye, H. Masursky, A. McEwen, D. Morrison, T. Owen, W. Owen, J. B. Pollack, C.C. Porco, K. Rages, P. Rogers, D. Rudy, C. Sagan, J. Schwartz, E.M. Shoemaker, M. Showalter, B. Sicardy, D. Simonelli, J. Spencer, L.A. Sromovsky, C. Stoker, R.G. Strom, V.E. Suomi, S.P. Synott, R.J. Terrile, P. Thomas, W.R. Thompson, A. Verbiscer, J. Veverka
The case for planetary sample return missions The case for planetary sample return missions
The essential role of planetary sample studies in exploration of the solar system has been well established “Drake et al., 1987”. As part of the larger pursuit of comparative planetology, samples of other rocky planets (Mercury, Venus, Mars), planetary satellites, asteroids, and comets should reveal much about the materials and processes that formed Earth. In that context, Mars is an...
Authors
James L. Gooding, M. H. Carr, Christopher P McKay
Geologic analyses of Shuttle Imaging Radar (SIR-B) data of Kilauea Volcano, Hawaii Geologic analyses of Shuttle Imaging Radar (SIR-B) data of Kilauea Volcano, Hawaii
Analyses of imaging radar data of volcanic terranes on Earth and Venus have emphasized the need for a clearer understanding of how these data can be most effectively used to accomplish important volcanological goals, including the interpretation of eruptive styles and the characterization of the geologic history of volcanic centers. The second Shuttle Imaging Radar experiment (SIR-B)...
Authors
Lisa R. Gaddis, Peter J. Mouginis-Mark, Robert B. Singer, Verne Kaupp
The competition between thermal contraction and differentiation in the stress history of the Moon The competition between thermal contraction and differentiation in the stress history of the Moon
The scarcity of both extension and compression features on the Moon strongly constrains the history of the lunar radius—to variations of less than ±1 km over the past 3.8 Gyr. This limit has traditionally been interpreted as requiring a delicate balance between thermal contraction of the near‐surface and expansion of a substantial cold interior region. Recent theories of lunar origin (e...
Authors
Randolph L. Kirk, David J. Stevenson