Last Chance is a layered rock outcrop found within the
Margaritifer Sinus quadrangle
The Margaritifer Sinus quadrangle is one of a series of list of quadrangles on Mars, 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Margaritifer Sinus quadrangle is also referred ...
(MC-19) region of the planet
Mars
Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...
, discovered by the
Mars Exploration Rover
NASA's Mars Exploration Rover (MER) mission was a robotic space mission involving two Mars rovers, ''Spirit (rover), Spirit'' and ''Opportunity (rover), Opportunity'', exploring the planet Mars. It began in 2003 with the launch of the two rove ...
''
Opportunity
Opportunity may refer to:
Places
* Opportunity, Montana, an unincorporated community, United States
* Opportunity, Nebraska, an unincorporated community, United States
* Opportunity, Washington, a former census-designated place, United States
* ...
'' in March 2004. The rock lies within the outcrop near the rover's landing site at
Meridiani Planum
Meridiani Planum (alternatively Terra Meridiani) is a large plain straddling the equator of Mars. The plain sits on top of an enormous body of sediments that contains bound water. The iron oxide in the spherules is crystalline (grey) hematite (Fe ...
, Mars.
Images returned show evidence for a geologic feature known as
ripple cross-stratification
In geology, cross-bedding, also known as cross-stratification, is layering within a stratum and at an angle to the main bedding plane. The sedimentary structures which result are roughly horizontal units composed of inclined layers. The origina ...
. At the base of the rock, layers can be seen dipping downward to the right. The bedding that contains these dipping layers is only one to two centimeters (0.4 to 0.8 inches) thick. In the upper right corner of the rock, layers also dip to the right, but exhibit a weak "concave-up" geometry. These two features—the thin, cross-stratified bedding combined with the possible concave geometry—suggest small ripples with sinuous crest lines. Although
wind
Wind is the natural movement of atmosphere of Earth, air or other gases relative to a planetary surface, planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heatin ...
can produce ripples, they rarely have sinuous crest lines and never form steep, dipping layers at such a small scale. The most probable explanation for these ripples is that they were formed in the presence of moving
water
Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...
.
See also
*
List of rocks on Mars
Martian rocks and outcrops have been studied ''in-situ'' by various landers and rovers. While many of the rocks identified on the Martian surface are similar to each other, some have been considered scientifically important or otherwise notabl ...
*
List of surface features of Mars imaged by ''Opportunity''
References
External links
Nasa's Mars Exploration Program
Mars Exploration Rover mission
Rocks on Mars
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