Under this scenario, sediments may have been transported into the lakes in regular, swift pulses, building up thin layers. Larger blocks of sediment may have been deposited when a lake became stagnant or deep enough to cause sediments to sift down through the water over longer intervals. If researchers can prove that Mars was once wet, it could be a significant boost for future Mars missions, with the ultimate goal being the search for signs of life, past or present. This just adds another point to that very convincing argument. And Aizenman points out that water is widely viewed as a necessary ingredient for life as we know it.
Massive units appear as one bulky rock layer with no clearly defined horizontal bedding.
In a few cases, these types appear together, with the massive unit always perched on top of the bedded unit. Thin mesa units, with surfaces ranging from smooth to pitted, to ridged and grooved, are almost always found on top of eroded massive or layered sedimentary rock. A paper on the images will appear in this Friday's issue of the journal Science . The findings were to be reported at a NASA news conference Thursday, after an embargo on the information lifted. That embargo was lifted today, after other news organizations published accounts of the study.