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Mars Express Captures Hourglass Crater
Paris France (SPX) Mar 19, 2006 ESA's Mars Express orbiter's High-Resolution Stereo Camera has compiled images and an accompanying video showing unusual flow deposits on the floors of two adjacent impact craters in the eastern Hellas Planitia region. The structures suggest possible glacial processes. The stereo capability of the HRSC makes it possible to animate 3D anaglyph images, based on digital elevation models. The image data were acquired during Mars Express orbit 451 from an altitude of 590 kilometers (378 miles) with an original resolution of 29 meters (94 feet) per pixel. The unusual hourglass-shaped structure is located in the southern-hemisphere highland terrain of Promethei Terra at the eastern rim of the Hellas Basin, at about latitude 38� South and longitude 104� East. Mission scientists said they think the surface morphology was formed by a "creep" of ice and debris, similar to either terrestrial rock glacier landforms or debris covered glaciers which are commonly found in high latitudes and alpine regions. Material called talus, or scree - broken rocks that lie on a steep mountainside or at the base of a cliff - and ice-rich debris probably accumulated at the base of the remnant massif and filled the upper bowl-shaped impact crater, which is approximately 9 kilometers (5.8 miles) wide. The debris-ice mixture then flowed through a breach in the crater rim into a 17-kilometer (11-mile) wide crater, some 500 meters (1,625 feet) below, taking advantage of the downward slope. The scientists said they are particularly interested in the age of these surfaces, which seem to be fairly intact over a wide area. There is some evidence glaciers were shaping the Martian surface at mid latitudes and even near the equator until only a few million years ago. Typical evidence for a significant loss of volatiles, such as pits and other depressions, can be observed on all debris surfaces surrounding the remnant massif. The statistical analysis of the number of craters formed by meteorite impacts used for age determination also shows that part of the surface with its present-day glacial characteristics was formed only a few million years ago. ESA scientists calculated the perspective views from the digital terrain model derived from the stereo channels. They have decreased image resolution for use on the Internet. Community Email This Article Comment On This Article Related Links Mars Express ESA Mars News and Information at MarsDaily.com Lunar Dreams and more
Spirit Says Good-Bye To Home Plate
Pasadena CA (SPX) Mar 18, 2006For the past several weeks, NASA's Spirit rover has been examining spectacular layered rocks exposed at a formation called Home Plate, in the Columbia Hills. The rover has been driving around Home Plate's northern and eastern edges of Home Plate, on the way to McCool Hill. |
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