A5088987866- Planetary Science and Exploration
- Astro and Planetary Science
- Space Exploration and Technology
- Geology and Paleoclimatology Research
- Space Science and Extraterrestrial Life
- Marine and environmental studies
- Aeolian processes and effects
- Scientific Research and Discoveries
- Methane Hydrates and Related Phenomena
- Spaceflight effects on biology
- Geological and Geochemical Analysis
- Gamma-ray bursts and supernovae
- Maritime and Coastal Archaeology
- earthquake and tectonic studies
- Isotope Analysis in Ecology
- Groundwater and Isotope Geochemistry
- Geological Studies and Exploration
- Paleontology and Stratigraphy of Fossils
- Cryospheric studies and observations
- Hydrocarbon exploration and reservoir analysis
- Geochemistry and Geologic Mapping
- Space exploration and regulation
- Geological Modeling and Analysis
- Geomagnetism and Paleomagnetism Studies
- Image Processing and 3D Reconstruction
Planetary Science Institute
2015-2024
Jet Propulsion Laboratory
2007
University of Arizona
2007
Ames Research Center
2000-2007
Astrogeology Science Center
2007
United States Geological Survey
2007
Search for Extraterrestrial Intelligence
2007
United States Department of the Interior
2003
Arizona State University
1998-2002
Southwest Research Institute
2001
Water has supposedly marked the surface of Mars and produced characteristic landforms. To understand history water on Mars, we take a close look at key locations with High-Resolution Imaging Science Experiment board Reconnaissance Orbiter, reaching fine spatial scales 25 to 32 centimeters per pixel. Boulders ranging up approximately 2 meters in diameter are ubiquitous middle high latitudes, which include deposits previously interpreted as finegrained ocean sediments or dusty snow. Bright...
Galileo data enable the major geological units, structures, and surface features to be identified on Europa. These include five primary units (plains, chaos, band, ridge, crater materials) their subunits, along with various tectonic structures such as faults. Plains are most widespread. Ridged plains material spans a wide range of ages, including oldest recognizable Europa, appears represent style resurfacing, rather than cryovolcanism. Smooth typically embays other terrains possibly type...
Images from the High Resolution Imaging Science Experiment have revealed new details on morphologic and topographic characteristics of slope streaks Mars. Over 1500 HiRISE images were analyzed with 78 unique image sites having streaks. low sun illumination reveal that dark relief where streaked surfaces are lower than their surroundings. Slope often initiate below localized features such as rock outcrops, individual boulders, impact craters. They also abundant in great numbers within blast...
Drainage densities on Mars range from zero over large areas of volcanic plains to 0.3–0.5 km −1 locally some volcanoes. These values refer geologic units, not drainage basins, as is normal for terrestrial densities. The highest are close the lowest derived by similar techniques. were determined every unit portrayed 1:15,000,000 map Mars. Except volcanoes with density dissected Noachian a 0.0074 . average units 0.0032 , Hesperian 0.00047 and Amazonian 0.00007 excluding 2–3 orders magnitude...
With a dynamic atmosphere and large supply of particulate material, the surface Mars is heavily influenced by wind‐driven, or aeolian, processes. The High Resolution Imaging Science Experiment (HiRISE) camera on Reconnaissance Orbiter (MRO) provides new view Martian geology, with ability to see decimeter‐size features. Current sand movement, evidence for recent bedform development, observed. Dunes ripples generally exhibit complex surfaces down limits resolution. Yardangs have diverse...
Abstract We apply machine learning techniques to identify and map resurfacing units in the central South Pole−Aitken (SPA) basin using three Lunar Reconnaissance Orbiter (LRO) mission data sets: 321/415 nm 566/689 band reflectance ratios from Hapke photometrically standardized albedo maps a Terrain Ruggedness Index Wilson et al. method. Other were considered, but topography key distinguishing between maria, cryptomaria, light plains. A two-step image classification approach was applied sets,...
The combination of Voyager images and newly acquired Galileo with low illumination resolutions ranging from 2 to 6 km/pixel now allows determination the global distribution mountains volcanic centers on Io. generally do not have characteristics typical terrestrial landforms, they are evenly distributed across surface show no obvious correlation known hot spots or plumes. Relative elevations, determined by shadow measurements stereoscopy, indicate that in imaged area range elevation up at...
The “Mitten” (provisionally named Murias Chaos by the International Astronomical Union) is a region of elevated chaos‐like terrain in leading hemisphere Europa. Its origin had been explained under currently debated theories melting through thin lithosphere or convection within thick one. Galileo observations reveal several characteristics that suggest Mitten distinct from typical chaos and point to different formational process. Photoclinometric elevation estimates slightly with respect...
During three close flybys in late 1999 and early 2000 the Galileo spacecraft acquired new observations of mountains that tower above Io's surface. These images have revealed surprising variety mountains' morphologies. They range from jagged peaks several kilometers high to lower, rounded structures. Some are very smooth, others covered by numerous parallel ridges. Many margins collapsing outward large landslides or series slump blocks, but a few steep, scalloped scarps. From these we can...
Abstract The discovery of global elemental volatile compositions, sublimation hollows, and chaotic terrains has significantly reshaped our understanding Mercury’s geology. These findings suggest the existence volatile-rich layers (VRLs) extending several kilometers in depth, challenging traditionally held view a predominantly volatile-devoid Mercury crust. However, precise nature origin these VRLs remain to be elucidated. Raditladi basin exhibits morphologies analogous terrestrial Martian...
Abstract The area in the Reiner Gamma swirl studied by Weirich et al. for topographic correlations also displays with Hapke-model-derived single-scattering albedo, surface roughness, and particle scattering properties unit. albedo associate compositional variations plagioclase FeO content photometric roughness show a rougher on-swirl, implying potentially more porous on-swirl compared to off-swirl. This suggests are dominated differences not structural differences, such as compaction....
The Galileo mission has revealed remarkable evidence of mass movement and landform degradation on Io. We recognize four major slope types observed a number intermediate resolution (∼250 m pixel −1 ) images several additional textures very high (∼10 images. Slopes scarps Io often show erosion, seen in the simplest form as alcove‐carving slumps slides at all scales. Many deposits are probably mostly consequence block release brittle failure. Sputtering plays no significant role. Sapping...
Galileo images of the Tyre Macula region Europa at regional (170 m/pixel) and local (∼40 scales allow mapping understanding surface processes landforms. Ridged plains, doublet complex ridges, shallow pits, domes, “chaos” areas, impact structures, tilted blocks massifs, young fracture systems indicate a history deformation on Europa. Regional morphologies suggest that an impactor penetrated through several kilometers water ice to mobile layer below. The morphology was initially dominated by...
Abstract The Moon's bright albedo markings, known as swirls, are defined by broad, bright, on‐swirl areas separated darker off‐swirl lanes. Their formation mechanism has long been debated and is key for understanding the processing of lunar surface, mobility soil particles, effects space environment on planetary surfaces. Here we present, first time, evidence that these features do not necessarily cross surface without regard to topography or local terrain. Within portions Mare Ingenii...
Galileo images reveal the presence of mass movement deposits within impact craters on Callisto. Eleven such were found in 830 candidate imaged at sufficient resolutions (86–280 m/pixel) for their identification. All are located craters, and sources appear to be crater wall material. The morphologies Callistan similar terrestrial movements rock glaciers. Rock glaciers involve ductile flow ice rock, but environment, water is likely undergo brittle deformation. Consequently, unlikely analogs...
Deuteronilus Mensae, first defined as an albedo feature at lat 35.0 deg N., long 5.0 E., by U.S. Geological Survey (USGS) and International Astronomical Union (IAU) nomenclature, is a gradational zone along the dichotomy boundary in northern mid-latitudes of Mars. The this location includes transition from rugged cratered highlands Arabia Terra to lowland plains Acidalia Planitia. Within polygonal mesas are prominent with features diagnostic Martian fretted terrain, including lobate debris...
Abstract Lunar swirls have been traditionally considered to be unaffected by topographic changes. Yet, correlations between areas of high albedo and lower elevations are observed in regions the Mare Ingenii swirl. Here, we apply similar techniques used at determine if swirl units topography also exist within Reiner Gamma. We generate using stereophotoclinometry Reconnaissance Orbiter Camera Narrow Angle images derive meter- submeter-scale topography. choose a 50 km 2 study region with 2.6 m...