Rover Image Reveals Fine Layering of Mars Bedrock;
Strata Could Indicate Past Presence of Water
By Kathy Sawyer
The Washington Post | Wednesday, January 28, 2004, pg. A03
PASADENA, Calif. Jan. 27—Scientists unveiled on Tuesday an image revealing fine-scale layering in the flat, tabular Martian bedrock close to the newly arrived rover Opportunity, saying they are on the verge of "arguably the coolest geologic field trip in human history."
Notwithstanding the jibes of late-night comedians about so much boring rock and dirt, rover chief scientist Steve Squyres of Cornell University could not contain his eagerness for a closer look at the formation in the rim of the small crater where Opportunity landed over the weekend.
"Look at that wonderful layer-cake structure in there," Squyres rhapsodized. "It's going to be fascinating -- beyond words -- to get up close and personal with this thing."
The rock formation -- the first bedrock encountered by the five U.S. landers that have reached Mars -- is less than 30 feet from the rover, a short drive away.
Using Opportunity's field geology tool kit, scientists are eager to find out whether the layering is actually sediment, formed by water when the planet was billions of years younger, or the result of volcanic ash deposits or other processes. The goal of Opportunity and its twin, Spirit, resting on what may be an ancient lake bed on the opposite side of the planet, is to search for signs that Mars once had liquid water long enough for life forms to develop.
Narrating as the panorama unfolded in black and white on a big screen here at the Jet Propulsion Laboratory, Squyres noted the left-to-right progression around roughly half of the crater rim, showing broken outcrops of rock slabs, then the first ribbons of layering in the rock surfaces, then a different-looking segment higher up, where the rocks are more massive and rounded, with sharp, jutting overhangs and, finally, even more distinct layering.
Mission scientist Andrew Knoll of Harvard University noted that each layer records a different period of history, a type of geological "document" familiar on Earth. "Probably every geologist in the world is developing opinions about" the Martian outcrops right now, he said. . .