Research Training Program

Megan Ennis
Morehead State University
Morehead, Kentucky

Tim McCoy, Ph.D.
Supervising Scientist
Department of Mineral Sciences

"Dreams can be wondrous, yet
nothing is as wonderful as a dream
come true, and being a part of the
Smithsonian National Museum of
Natural History this summer has
truly been a dream come true."

More Evidence of Water on Mars?

The question, "Is there evidence of water on Mars?" has been on the minds of many planetary scientists, and until recently they could only speculate on the possibilities. In January of 2004, NASA successfully landed the rovers Spirit and Opportunity on opposite sides of Mars. The mission objective is to find evidence of water on Mars. While Opportunity discovered indications of past water upon landing, Spirit has operated for more than two years before finding promising evidence for water on Mars. After passing through the Columbia Hills, Spirit came upon a large light-toned circular feature, about 80 meters in diameter, which was named "Home Plate." The terrain was different than any that had been previously encountered. At Home Plate there are three distinguishable rock layers. The coarser grained bottom layer contains holes (vesicles), where gases are presumed to have escaped from an initial volcanic eruption. Above this is a finer unit, which may represent an ash deposit. Cross-beds, found in the upper unit, were suggested to be a typical deposit of reworked, wind-blown sediments. If correct, this requires two distinct episodes for the formation of Home Plate, with an initial volcanic eruption followed by a prolonged period of wind reworking. This idea was tested by examining known Earth structures such as volcanic craters in New Mexico, including the Zuni Salt Lake where similar features were found. These features occur over vertical distances similar to that seen in Home Plate on Mars. This suggests that a single volcanic eruption, with hot lava interacting with water during its rise to the surface can explain all of the features of both Home Plate and Zuni Salt Lake, without requiring later wind-reworking, and thus offering further evidence that water may have once been present on Mars.

This research was supported by a grant from NMNH Office of the Director.

Letter of gratitude