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
'Shaler' Unit's Evidence of Stream FlowThis image from the Mast Camera (Mastcam) on NASA's Mars rover Curiosity shows inclined layering known as cross-bedding in an outcrop called "Shaler" on a scale of a few tenths of meters, or decimeters (1 decimeter is nearly 4 inches). The superimposed scale bar is 50 centimeters (19.7 inches). An unannotated version is also available.
This stratigraphic unit is called the Shaler Unit. Decimeter-scale cross-bedding in the Shaler Unit is indicative of sediment transport in stream flows. Currents mold the sediments into small underwater dunes that migrate downstream. When exposed in cross-section, evidence of this migration is preserved as strata that are steeply inclined relative to the horizontal -- thus the term "cross-bedding." The grain sizes here are coarse enough to exclude wind transport. This cross-bedding occurs stratigraphically above the Gillespie Unit in the "Yellowknife Bay" area of Mars' Gale Crater, and is therefore geologically younger.
Mastcam obtained the image on the 120th Martian day, or sol, of Curiosity's surface operations (Dec. 7, 2012).
The image has been white-balanced to show what the rock would look like if it were on Earth.
Image Credit: NASA/JPL-Caltech/MSSS