05.15.2017 From 'Tribulation' to 'Perseverance' on Mars
03.29.2017 A Decade of Compiling the Sharpest Mars Map
03.09.2017 Back-to-Back Martian Dust Storms
02.08.2017 Mars Reconnaissance Orbiter Observes Changes
01.25.2017 'Wing' Dike of Hardened Lava in New Mexico
01.25.2017 Blade-Like Martian Walls Outline Polygons
01.06.2017 Earth and Its Moon, as Seen From Mars
11.15.2016 Schiaparelli Impact Site on Mars, Stereo
11.03.2016 Schiaparelli Impact Site on Mars, in Color
03.30.2016 Erisa Hines
03.30.2016 Buzz Aldrin
03.21.2016 For a Decade Orbiting Mars: One Recent View
03.09.2016 For a Decade Orbiting Mars: One Recent View
03.09.2016 Mars Reconnaissance Orbiter By the Numbers
03.01.2016 MRO sees Frosty Spring Slopes
02.12.2016 Women in Science
02.10.2016 Wind at Work
11.16.2015 Change Observed in Martian Sand Dune
10.05.2015 'The Martian' Story's Ares 4 Landing Site
10.05.2015 The Ares 3 Landing Site (Figure A)
09.30.2015 Avalanche Ho!
06.29.2015 Mars Exploration Zone Layout Considerations
06.17.2015 Active High-Latitude Dune Gullies
06.03.2015 Crisp Crater in Sirenum Fossae
05.20.2015 Sedimentary Rock Layers on a Crater Floor
05.20.2015 Honey, I Shrunk the Mesas
05.11.2015 Icy Wonderland
05.04.2015 Diverse Orbits Around Mars
03.27.2015 South Pole Spiders
03.27.2015 A Smile a Day....
03.25.2015 Pitted Landforms in Southern Hellas Planitia
03.12.2015 Curiosity Heading Away from 'Pahrump Hills'
02.18.2015 Lava Flow Near the Base of Olympus Mons
02.09.2015 Yardangs in Arsinoes Chaos, Mars
02.04.2015 Curiosity Rover at 'Pahrump Hills'
01.22.2015 Frost on Crater Slope
Layered Outcrops on Crater FloorThis image shows part of the floor of an impact crater on the northern rim of the giant Hellas Basin.
Hellas includes the lowest elevations on Mars, and may have once held lakes or seas; layered rock outcrops occur around much of the edge of the basin. At this site, a large impact crater (about 90 kilometers across) was partly filled by layered rocks. These rocks on the crater floor are now eroding and forming strange pits.
Here, the layers are mostly exposed on a steep slope which cuts across much of the image. On this slope, they crop out as rocky stripes, some continuous and others not. The material between the stripes is mostly covered by debris, but some areas of exposed rock are visible. The slope is capped by a thick, continuous layer that armors it against erosion; once this cap is gone, the lower material is removed rapidly, forming the steep slope. At the base of this slope, rocks on the floor of the pit appear bright and heavily fragmented by cracks known as joints.
The variation in rock types suggests that the rocks here were deposited by multiple processes or in different environments. Sites like this may preserve a record of conditions on early Mars.
Image Credit: NASA/JPL-Caltech/Univ. of Arizona