02.08.2017 Mars Reconnaissance Orbiter Observes Changes
01.26.2017 Mono Lake
01.25.2017 'Wing' Dike of Hardened Lava in New Mexico
01.25.2017 Blade-Like Martian Walls Outline Polygons
01.23.2017 Spirit And Opportunity By The Numbers
01.10.2017 Mars 2020 Rover - Artist's Concept
01.06.2017 Earth and Its Moon, as Seen From Mars
12.13.2016 Now and Long Ago at Gale Crater, Mars
12.13.2016 Where's Boron? Mars Rover Detects It
11.15.2016 Schiaparelli Impact Site on Mars, Stereo
11.03.2016 Schiaparelli Impact Site on Mars, in Color
10.17.2016 MAVEN Captures Rapid Cloud Formation
10.17.2016 Mars' Nightside Atmosphere
10.17.2016 Ultraviolet Image Near Mars' South Pole
10.17.2016 Ultraviolet Mars Reveals Cloud Formation
10.05.2016 Dust Haze Hiding the Martian Surface in 2001
10.04.2016 Test of Lander Vision System for Mars 2020
10.03.2016 A Sharpened Ultraviolet View of Mars
10.03.2016 Curiosity Self-Portrait at 'Murray Buttes'
10.03.2016 Butte 'M9a' in 'Murray Buttes' on Mars
09.19.2016 Ribbon Cutting
09.09.2016 Farewell to Murray Buttes (Image 5)
09.09.2016 Farewell to Murray Buttes (Image 4)
09.09.2016 Farewell to Murray Buttes (Image 3)
09.09.2016 Farewell to Murray Buttes (Image 2)
09.09.2016 Farewell to Murray Buttes (Image 1)
08.26.2016 Out-of-this-World Records
08.04.2016 Mars Rover Is New Social Media Game
08.04.2016 Mars Rover Social Media Game
08.02.2016 Artist Concept for RIMFAX
07.20.2016 Viking 40 Year Anniversary Artwork: Medal
07.18.2016 Mars 2020 Range Trigger
07.14.2016 NASA to Launch Mars Rover in 2020
Distal Rampart of Crater in Chryse PlanitiaImpact craters on Mars are kind of neat. Many of them look very different than impact craters seen on Earth's moon or Mercury. Fresh lunar and Mercurian craters have ejecta blankets that look a bit rough near the crater rims; around larger craters, long rays or chains of secondary craters radiate away from the crater rims. Some Martian craters are similar to these craters, but Mars also has a high proportion of craters with forms not found on the moon or Mercury: rampart craters.
Rampart craters, also called fluidized-ejecta craters, have ejecta blankets that appear lobate, or rounded, in plan view, and end in low ridges or ramparts. An example of a such a rampart is the ridge in this image from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter. Here you see the rampart at the edge of an ejecta blanket that comes from an approximately 16-kilometer-diameter (10-mile-diameter) crater, about 16 kilometers (10 miles) to the east.
For years there has been a debate about whether these lobes and ramparts were formed by ejecta interacting with the thin Martian atmosphere, or whether they formed because volatiles (such as water or ice) in the subsurface were incorporated into the ejecta material excavated by the impact. The common consensus is now in favor of the volatile hypothesis. Because of this, rampart craters can be used to indicate the past presence of water or ice in the Martian crust.
This image covers a swath of ground about 6 kilometers (4 miles) wide, centered at 17.2 degrees north latitude, 311.6 degrees east longitude. It is one product from HiRISE observation ESP_14417_1975, made on Aug. 23, 2009. Other image products from this observation are available at http://hirise.lpl.arizona.edu/ESP_014417_1975.
Image Credit: Image Credit: NASA/JPL-Caltech/University of Arizona