James Head - Academia.edu (original) (raw)
Papers by James Head
The lunar farside South Pole-Aitken Basin is the largest and oldest documented basin on the Moon ... more The lunar farside South Pole-Aitken Basin is the largest and oldest documented basin on the Moon and is thus of interest from the point of view of the scale of production of impact melt at large basin-event sizes and its ring structure and potential depth of sampling at such a large diameter. We used new LOLA data from the Lunar
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We use a new global crater catalog mapped using Lunar Orbiter Laser Altimeter data to examine the... more We use a new global crater catalog mapped using Lunar Orbiter Laser Altimeter data to examine the stratigraphy of lunar impact basins. This catalog allows us to calculate crater statistics for many basins and determine their relative sequence.
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This study is part of the larger Venus Global Dyke Swarm Map project, which has the goals of (1) ... more This study is part of the larger Venus Global Dyke Swarm Map project, which has the goals of (1) producing a global map of graben-fissure systems, (2) assessing which systems are underlain by dyke swarms, and (3) contributing to the understanding of the tectonic and magmatic history of the planet. Graben-fissure systems on Venus are comprised of extensional lineaments, related
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The Moon Mineralogy Mapper (M3) is a guest instrument on Chandrayaan-1, India's first mission... more The Moon Mineralogy Mapper (M3) is a guest instrument on Chandrayaan-1, India's first mission to the Moon. M3 is an imaging spectrometer covering the wavelength range of 430 nm - 3000 nm, and was designed to map the mineralogy of the lunar surface. The high spectral resolution of M3 enables the diagnostic absorption features of lunar minerals to be identified clearly, while the high spatial resolution of M3 allows the identification and mapping of distinct lithologic units. Olivine is an important mineral with which to interpret the petrologic evolution of igneous rocks. The composition of olivine (Mg#) is used to indicate the degree of evolution of the source magma from which a sample crystallized. Visible to near-infrared reflectance spectroscopy is sensitive to the Mg# of olivine, as the diagnostic olivine absorption features shift in response to changing major element abundances (Mg and Fe) content. These changes in diagnostic absorption features can be detected by modeling ...
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We suggest that hydrothermal alteration of magnetic carriers within the crust beneath Martian low... more We suggest that hydrothermal alteration of magnetic carriers within the crust beneath Martian lowlands and basins may have contributed to the pattern of crustal magnetization observed today.
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Science, 2005
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Motivated by the latest data from Mars Global Surveyor and from recent analyses of Martian meteor... more Motivated by the latest data from Mars Global Surveyor and from recent analyses of Martian meteorites, we offer a new synthesis of the relative timing of major events in the early geological history of Mars together with associated uncertainties.
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Solar System Research, 2005
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MESSENGER's first two flybys of Mercury provide new insights into Mercury's dynamic past ... more MESSENGER's first two flybys of Mercury provide new insights into Mercury's dynamic past and reveal a planet rich in color and compositional diversity. Including images from Mariner 10, over 90% of Mercury has now been observed at resolutions >2 km/pixel, and 80% of the planet has been observed in the 11 colors of the Mercury Dual Imaging System's wide-angle camera
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We present preliminary crater counts for various terrains on Ganymede (including Uruk Sulcus, Gal... more We present preliminary crater counts for various terrains on Ganymede (including Uruk Sulcus, Galileo Regio, and the 'unnamed sulcus'), Europa, and the Valhalla region of Callisto. A single generalization is that craters less than several hundred m diameter are unexpectedly underabundant, never approaching saturation densities even on the terrains of Ganymede and Callisto that appear saturated by large craters. The
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Triple bands (TB) are linear features discovered on the Galilean satellite, Europa, during the Vo... more Triple bands (TB) are linear features discovered on the Galilean satellite, Europa, during the Voyager mission. TB consist of a central bright stripe averaging one to two km in width, flanked by two parallel low-albedo stripes, each several km or more across. Multispectral imaging data acquired by the Galileo spacecraft provide new insight into the possible origin(s) for TB. Two
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New Galileo SSI imaging of Io from orbits C30-I33 will be presented. The aging Galileo spacecraft... more New Galileo SSI imaging of Io from orbits C30-I33 will be presented. The aging Galileo spacecraft continues to produce spectacular new results, including the tallest volcanic plume yet found on Io.
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During the second MESSENGER flyby of Mercury on October 6, 2008, MESSENGER will pass over part of... more During the second MESSENGER flyby of Mercury on October 6, 2008, MESSENGER will pass over part of the planet previously imaged by the Mariner 10 spacecraft. The Mercury Atmospheric and Surface Composition Spectrometer (MASCS) will obtain the first high-spatial-resolution (< 10 km) spectra of this hemisphere, measuring reflectance spectra from Mercury's surface over the wavelength range 220-1450 nm along an
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During the first MESSENGER flyby of Mercury on January 14, 2008, the Mercury Atmospheric and Surf... more During the first MESSENGER flyby of Mercury on January 14, 2008, the Mercury Atmospheric and Surface Composition Spectrometer (MASCS) measured reflectance spectra from Mercury's surface over the wavelength range 220-1450 nm. These are the first high-spatial-resolution (<10 km) spectra at any wavelength and the first reported ultraviolet (UV, wavelength < 360 nm) observations of the surface. MASCS observed the sunlit
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The lunar farside South Pole-Aitken Basin is the largest and oldest documented basin on the Moon ... more The lunar farside South Pole-Aitken Basin is the largest and oldest documented basin on the Moon and is thus of interest from the point of view of the scale of production of impact melt at large basin-event sizes and its ring structure and potential depth of sampling at such a large diameter. We used new LOLA data from the Lunar
Bookmarks Related papers MentionsView impact
We use a new global crater catalog mapped using Lunar Orbiter Laser Altimeter data to examine the... more We use a new global crater catalog mapped using Lunar Orbiter Laser Altimeter data to examine the stratigraphy of lunar impact basins. This catalog allows us to calculate crater statistics for many basins and determine their relative sequence.
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This study is part of the larger Venus Global Dyke Swarm Map project, which has the goals of (1) ... more This study is part of the larger Venus Global Dyke Swarm Map project, which has the goals of (1) producing a global map of graben-fissure systems, (2) assessing which systems are underlain by dyke swarms, and (3) contributing to the understanding of the tectonic and magmatic history of the planet. Graben-fissure systems on Venus are comprised of extensional lineaments, related
Bookmarks Related papers MentionsView impact
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The Moon Mineralogy Mapper (M3) is a guest instrument on Chandrayaan-1, India's first mission... more The Moon Mineralogy Mapper (M3) is a guest instrument on Chandrayaan-1, India's first mission to the Moon. M3 is an imaging spectrometer covering the wavelength range of 430 nm - 3000 nm, and was designed to map the mineralogy of the lunar surface. The high spectral resolution of M3 enables the diagnostic absorption features of lunar minerals to be identified clearly, while the high spatial resolution of M3 allows the identification and mapping of distinct lithologic units. Olivine is an important mineral with which to interpret the petrologic evolution of igneous rocks. The composition of olivine (Mg#) is used to indicate the degree of evolution of the source magma from which a sample crystallized. Visible to near-infrared reflectance spectroscopy is sensitive to the Mg# of olivine, as the diagnostic olivine absorption features shift in response to changing major element abundances (Mg and Fe) content. These changes in diagnostic absorption features can be detected by modeling ...
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We suggest that hydrothermal alteration of magnetic carriers within the crust beneath Martian low... more We suggest that hydrothermal alteration of magnetic carriers within the crust beneath Martian lowlands and basins may have contributed to the pattern of crustal magnetization observed today.
Bookmarks Related papers MentionsView impact
Science, 2005
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Motivated by the latest data from Mars Global Surveyor and from recent analyses of Martian meteor... more Motivated by the latest data from Mars Global Surveyor and from recent analyses of Martian meteorites, we offer a new synthesis of the relative timing of major events in the early geological history of Mars together with associated uncertainties.
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Solar System Research, 2005
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MESSENGER's first two flybys of Mercury provide new insights into Mercury's dynamic past ... more MESSENGER's first two flybys of Mercury provide new insights into Mercury's dynamic past and reveal a planet rich in color and compositional diversity. Including images from Mariner 10, over 90% of Mercury has now been observed at resolutions >2 km/pixel, and 80% of the planet has been observed in the 11 colors of the Mercury Dual Imaging System's wide-angle camera
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We present preliminary crater counts for various terrains on Ganymede (including Uruk Sulcus, Gal... more We present preliminary crater counts for various terrains on Ganymede (including Uruk Sulcus, Galileo Regio, and the 'unnamed sulcus'), Europa, and the Valhalla region of Callisto. A single generalization is that craters less than several hundred m diameter are unexpectedly underabundant, never approaching saturation densities even on the terrains of Ganymede and Callisto that appear saturated by large craters. The
Bookmarks Related papers MentionsView impact
Triple bands (TB) are linear features discovered on the Galilean satellite, Europa, during the Vo... more Triple bands (TB) are linear features discovered on the Galilean satellite, Europa, during the Voyager mission. TB consist of a central bright stripe averaging one to two km in width, flanked by two parallel low-albedo stripes, each several km or more across. Multispectral imaging data acquired by the Galileo spacecraft provide new insight into the possible origin(s) for TB. Two
Bookmarks Related papers MentionsView impact
New Galileo SSI imaging of Io from orbits C30-I33 will be presented. The aging Galileo spacecraft... more New Galileo SSI imaging of Io from orbits C30-I33 will be presented. The aging Galileo spacecraft continues to produce spectacular new results, including the tallest volcanic plume yet found on Io.
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During the second MESSENGER flyby of Mercury on October 6, 2008, MESSENGER will pass over part of... more During the second MESSENGER flyby of Mercury on October 6, 2008, MESSENGER will pass over part of the planet previously imaged by the Mariner 10 spacecraft. The Mercury Atmospheric and Surface Composition Spectrometer (MASCS) will obtain the first high-spatial-resolution (< 10 km) spectra of this hemisphere, measuring reflectance spectra from Mercury's surface over the wavelength range 220-1450 nm along an
Bookmarks Related papers MentionsView impact
During the first MESSENGER flyby of Mercury on January 14, 2008, the Mercury Atmospheric and Surf... more During the first MESSENGER flyby of Mercury on January 14, 2008, the Mercury Atmospheric and Surface Composition Spectrometer (MASCS) measured reflectance spectra from Mercury's surface over the wavelength range 220-1450 nm. These are the first high-spatial-resolution (<10 km) spectra at any wavelength and the first reported ultraviolet (UV, wavelength < 360 nm) observations of the surface. MASCS observed the sunlit
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