Scientists found a variety of rock types in the Columbia Hills, and they placed them into six different categories. The six are: Clovis, Wishbone, Peace, Watchtower, Backstay, and Independence. They are named after a prominent rock in each group. Their chemical compositions, as measured by APXS, are significantly different from each other. Most importantly, all of the rocks in Columbia Hills show various degrees of alteration due to aqueous fluids. They are enriched in the elements phosphorus, sulfur, chlorine, and bromine—all of which can be carried around in water solutions. The Columbia Hills’ rocks contain basaltic glass, along with varying amounts of olivine and sulfates. The olivine abundance varies inversely with the amount of sulfates. This is exactly what is expected because water destroys olivine but helps to produce sulfates.
The Clovis group is especially interesting because the Mossbauer spectrometer(MB) detected goethite in it. Goethite forms only in the presence of water, so its discovery is the first direct evidence of past water in the Columbia Hills's rocks. In addition, the MB spectra of rocks and outcrops displayed a strong decline in olivine presence, although the rocks probably once contained much olivine. Olivine is a marker for the lack of water because it easily decomposes in the presence of water. Sulfate was found, and it needs water to form. Wishstone contained a great deal of plagioclase, some olivine, and anhydrate (a sulfate). Peace rocks showed sulfur and strong evidence for bound water, so hydrated sulfates are suspected. Watchtower class rocks lack olivine consequently they may have been altered by water. The Independence class showed some signs of clay (perhaps montmorillonite a member of the smectite group). Clays require fairly long term exposure to water to form. One type of soil, called Paso Robles, from the Columbia Hills, may be an evaporate deposit because it contains large amounts of sulfur, phosphorus, calcium, and iron. Also, MB found that much of the iron in Paso Robles soil was of the oxidized, Fe+++ form, which would happen if water had been present.
Towards the middle of the six year mission (a mission that was supposed to last only 90 days), large amounts of pure silica were found in the soil. The silica could have come from the interaction of soil with acid vapors produced by volcanic activity in the presence of water or from water in a hot spring environment.
After Spirit stopped working scientists studied old data from the Miniature Thermal Emission Spectrometer, or Mini-TES and confirmed the presence of large amounts of carbonate-rich rocks, which means that regions of the planet may have once harbored water. The carbonates were discovered in an outcrop of rocks called "Comanche."
In summary, Spirit found evidence of slight weathering on the plains of Gusev, but no evidence that a lake was there. However, in the Columbia Hills there was clear evidence for a moderate amount of aqueous weathering. The evidence included sulfates and the minerals goethite and carbonates which only form in the presence of water. It is believed that Gusev crater may have held a lake long ago, but it has since been covered by igneous materials. All the dust contains a magnetic component which was identified as magnetite with some titanium. Furthermore the thin coating of dust that covers everything on Mars is the same in all parts of Mars.
Read more about this topic: Aeolis Quadrangle, What Spirit Rover Discovered About Rocks and Minerals On Mars
Other articles related to "columbia hills, hill, hills, columbia":
... the first of many targets at the base of the Columbia Hills called West Spur ... From here, Spirit took a northerly path along the base of the hill towards the target Wooly Patch, which was studied from Sol 192 to Sol 199 ... By Sol 203, Spirit had driven southward up the hill and arrived at the rock dubbed "Clovis" ...
... The Columbia Hills are a range of low hills inside Gusev crater on Mars ... The hills lie approximately 3 kilometres (1.9 mi) away from the rover's original landing position ... The range is named to memorialize the Space Shuttle Columbia disaster ...
Columbia Hills can refer to the following:
- Columbia Hills (Washington), an area of hills in Washington state, USA
- Columbia Hills State Park, a Washington state park in the area of the same name.
- Columbia Hills (Mars), a range of low hills inside Gusev crater on Mars
Famous quotes containing the words hills and/or columbia:
“A lake is the landscapes most beautiful and expressive feature. It is earths eye; looking into which the beholder measures the depth of his own nature. The fluviatile trees next the shore are the slender eyelashes which fringe it, and the wooded hills and cliffs around are its overhanging brows.”
—Henry David Thoreau (18171862)
“The young women, what can they not learn, what can they not achieve, with Columbia University annex thrown open to them? In this great outlook for womens broader intellectual development I see the great sunburst of the future.”
—M. E. W. Sherwood (18261903)