|Conglomerate boulder (Commons)|
Such rocks can tell us a lot about the kind of environment that they were deposited in; fluvial, glacial, marine and others.If you recall dear reader Curiosity is currently in an area within an alluvial fan and therefore such materials are invaluable to study up close. According to the speakers at the conference, this is the first time they have seen such rocks up close (though they have seen them from orbit in places such as Holden crater).
Three rocks turned out to be conglomerates according to the speakers and they all apparently belong to the same layer of bedrock, starting with the exposed one back at the landing site; the scour mark dubbed 'Goulburn'.
|The scour marks exposed bedrock consisting of conglomerate (NASA/JPL/annotation by me)|
|Hottah looking like a broken up street curb. It is tilted maybe because of shock from a recent meteorite impact. Note the 10cm scale bar. (NASA/JPL/MSSS)|
|The rounded clast circled in white. The gravel pile to the left are clasts eroded out of the rock by wind erosion probably (NASA/JPL/MSSS)|
The speakers also pointed out that the valley from which the alluvial fan originates from has been officially named 'Peace vallis' by the International Astronomical Union (IAU) the top body for astronomical nomenclature.
|Peace vallis is seen in the left corner of this elevation map. Bradbury landing is marked with a cross (NASA/JPL/UA)|
So there you have it, 'fossil' (fossil here does not imply bones or remains of living organisms) evidence of a Martian stream. Exciting times! If you would like to learn more about conglomerates, visit this article on geology.com.
|The rock 'Link' versus a terrestrial example of a conglomerate rock with a known water history (NASA/JPL/MSSS & PSI)|