Thursday, June 28, 2012

Excavating Water-Rich Rocks

The large 25 km-diameter crater in the foreground of this High Resolution Stereo Camera (HRSC) perspective view has excavated rocks which have been altered by groundwater in the crust before the impact occurred. Using OMEGA (Visible and Infrared Mineralogical Mapping Spectrometer) on ESA's Mars Express and CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) on NASA's Mars Reconnaissance Orbiter (MRO), scientists have identified hydrated minerals in the central mound of the crater, on the crater walls and on the large ejecta blanket around the crater. Hydrated minerals were found in 175 locations associated with other nearby craters in the Tyrrhena Terra region of Mars.

Photo credit: Mars Express HRSC, ESA/DLR/FU Berlin (G. Neukum); NASA/MOLA Science Team; D. Loizeau et al.

Note: For more information, see Craters Expose Action of Groundwater Beneath Martian Highlands.

Monday, June 18, 2012

Bright Material along the Floor of a Trough in Noctis Labyrinthus

Many of the troughs (or, rounded depressions) of Noctis Labyrinthus contain bright, sometimes layered, materials. Noctis Labyrinthus is located on the far western end of the large canyon system Valles Marineris. To the west lie the volcanoes of Tharsis.

This HiRISE image shows an example of the bright material commonly found along the floors of some of the Noctis troughs. Spectral data from the CRISM instrument, also onboard the MRO spacecraft, indicate the bright material is hydrated (i.e., contains water). The hydrated material may have formed when water upwelled into the low-lying depression or when ice within the trough melted due to heating from volcanic activity.

An earlier image taken of this same location will now be combined with this new image to produce a stereo anaglyph. The stereo should allow scientists to understand the relationship between the bright material and the darker rocks that make up the trough floor.

This is a stereo pair with ESP_017399_1680.

Photo credit: NASA/JPL/University of Arizona

Saturday, June 9, 2012

Pluvo Point

This image near Mars' North Pole was a public image suggestion, with the following rationale: "My three year old son has dubbed this white smudge 'Pluvo Point', he thinks 'we should take a picture of it to learn about how snow and ice comes down on Mars.'"

Although we can clearly see the bright area in this image, it isn't due to frost or ice at this time of year (early summer), and doesn't have the relatively blue color expected for frost. So, what does create the "white smudge"?

The image shows a typical region of northern plains covered by polygons and boulders. There are dark areas in low spots that are probably due to windblown dark sand. Where the sand is most abundant, it forms the dunes seen near the top and bottom of this image. The "white smudge" appears to be a region with relatively little dark sand. It isn't actually white, but it is brighter than other nearby regions. These could be low hills where the sand doesn't collect.

Photo credit: NASA/JPL/University of Arizona

Note: This site is located in Vastitas Borealis to the south of Gemini Scopuli; the closest named feature is Inuvik Crater, which is to the north.

Friday, June 8, 2012

Danielson and Kalocsa Craters

High-Resolution Stereo Camera (HRSC) nadir and color channel data taken on 19 June 2011 by ESA’s Mars Express have been combined to form a natural-color view of the Danielson and Kalocsa craters and their environment in the Arabia Terra region. Centered at around 7°N and 353°E, this image has a ground resolution of about 26 m per pixel. The image shows the yardangs bisected by the darker dune field in Danielson Crater.

Photo credit: ESA/DLR/FU Berlin (G. Neukum)

Note: Danielson crater is the impact crater on the right.

Monday, June 4, 2012

Near the Mouth of Morava Valles

Morava Valles drained Ladon Basin and discharged towards the large regions of chaotic terrain near the head of Ares Vallis.

Because the valley emerges full bore from Ladon Basin (much like the Niagara River emerges from Lake Erie on the Earth), it has been hypothesized that it was formed when a lake overflowed the basin.

There are numerous valleys, including the large Ladon Valles, that end along the margin of Ladon Basin. Some of the outcrops visible in this image and elsewhere in the basin show evidence of layering due to deposition of sediments.

Comparison of the nature and extent of layers exposed here and elsewhere around Ladon basin should help to constrain their origin, by water flow or other processes.

Photo credit: NASA/JPL/University of Arizona

Sunday, June 3, 2012

Landforms in Cerberus Fossae

The landforms in this observation are quite diverse, with a segment of the Cerberus Fossae (a deep trough extending east-west) and surrounding terrain that has been eroded by some fluid, either water or lava.

There are many boulders in places, either on steep slopes or excavated by impact craters. The high hills are islands of older terrain surrounded by younger lavas.

Be sure to check out the stereo anaglyph.

This is a stereo pair with ESP_026712_1960.

Photo credit: NASA/JPL/University of Arizona

Note: I have modified this title from "Landforms Near Grjotá Valles" to Landforms in "Cerberus Fossae." Grjotá Valles is some distance off to the east from the location in the above image. This site is actually in the heart of Cerberus Fossae, hence the title change.

Saturday, June 2, 2012

Streamlined Hills in Elysium Planitia

This observation was taken to investigate the topography of hills that were eroded by floods of water or lava. In many locations near here it is clear that the last fluid to flow through the region was lava.

Clear margins of lava flows are visible as well as lava textures on the channel floor. In this location, the cover of wind-blown sand and the effect of many small impact craters has erased such obvious indicators of lava. This is likely because the lava coating is thin and can be easily erased.

However, it is also possible that no lava passed through this location. Further investigation of these data should help us better understand the role of water and lava in changing the Martian landscape.

This is a stereo pair with ESP_025802_1960.

Photo credit: NASA/JPL/University of Arizona

Note: This hill is located in Phlegra Dorsa in the immediate vicinity of Grjotá Valles.

Friday, June 1, 2012

Different Materials Exposed along a Wallrock Slope in Coprates Chasma

This image shows several kilometers of topography exposed along the wallrock within Coprates Chasma. Higher topography is towards the bottom of the image while the floor of Coprates Chasma is visible at the top of the image.

There are patches of brighter materials exposed within the wallrock and along the chasma floor. The bright massive rocks exposed in the wallrock likely represent weathered rocks that have altered to this brighter material.

Lower down the wallrock and along the chasma floor, the brighter material appears layered and could represent sediments deposited within the chasma when water or ice may have existed here. The image also shows finer material composed of eroded wallrock and aeolian debris that is mass wasting downslope.

Photo credit: NASA/JPL/University of Arizona

Note: This image is located in far eastern Coprates Chasma, near the entrance of Capri Chasma. The closest named feature is Saravan Crater, to the south.