National Aeronautics and Space Administration Logo
Follow this link to skip to the main content NASA Banner
Solar System Exploration
Multimedia
Detail in 'Point Lake' Outcrop
Detail in 'Point Lake' Outcrop (click to enlarge)
 
 

Detail in 'Point Lake' Outcrop
Date: 13 Jun 2013

The Mars Hand Lens Imager (MAHLI) on the arm of NASA's Mars rover Curiosity was positioned about 4 inches (10 centimeters) from the surface of the "Point Lake" outcrop when it took this image of a portion of the outcrop's steep face. This close-up view and others from MAHLI on the same Martian day -- Sol 303 of the mission (June 13, 2013) -- show that many holes in the rock are occupied by what appears to be material different from that of the main rock itself. Specifically, the material in the holes seems to be finer-grained, slightly darker, and slightly more resistant to weathering. In many instances, there is a moat of sorts between the more resistant interior material and the main Point Lake rock.

In this image, the larger hole containing a darker inclusion with a fleck of bright material in the moat is roughly 1 inch (2.5 centimeters) in diameter.

Curiosity's science team chose to approach Point Lake with the rover in June 2013 to get a closer look after earlier imaging of Point Lake (such as at http://photojournal.jpl.nasa.gov/catalog/PIA17071) left uncertainty about whether this outcrop is igneous or sedimentary.

A closer look still leaves room for interpretation. The material in the holes observed with MAHLI could be pebbles that blew into pre-existing holes, but it seems unlikely that the same type of pebble would blow into every hole. They might be pebbles that were part of the rock all along, as would be expected if Point Lake is sandstone with a few coarser pebbles (and therefore supporting the sedimentary interpretation). If Point Lake is igneous, the material in the holes might be individual, larger crystals within an otherwise finer-crystalline rock. Such crystals are called phenocrysts, and indicate that they got a head start on cooling before the rest of the rock was erupted onto the surface. Finally, the material in the holes could be secondary -- having been deposited at a later time in pre-existing holes of the rock from percolating fluids or gases. This last scenario could fit either the sedimentary or igneous interpretation, without favoring one over the other.

Credit: NASA/JPL-Caltech/MSSS



Awards and Recognition   Solar System Exploration Roadmap   Contact Us   Site Map   Print This Page
NASA Official: Kristen Erickson
Advisory: Dr. James Green, Director of Planetary Science
Outreach Manager: Alice Wessen
Curator/Editor: Phil Davis
Science Writer: Autumn Burdick
Producer: Greg Baerg
Webmaster: David Martin
> NASA Science Mission Directorate
> Budgets, Strategic Plans and Accountability Reports
> Equal Employment Opportunity Data
   Posted Pursuant to the No Fear Act
> Information-Dissemination Policies and Inventories
> Freedom of Information Act
> Privacy Policy & Important Notices
> Inspector General Hotline
> Office of the Inspector General
> NASA Communications Policy
> USA.gov
> ExpectMore.gov
> NASA Advisory Council
> Open Government at NASA
Last Updated: 25 Jun 2013