RESUMEN
The Alpha Particle X-ray Spectrometer on the Opportunity rover determined major and minor elements of soils and rocks in Meridiani Planum. Chemical compositions differentiate between basaltic rocks, evaporite-rich rocks, basaltic soils, and hematite-rich soils. Although soils are compositionally similar to those at previous landing sites, differences in iron and some minor element concentrations signify the addition of local components. Rocky outcrops are rich in sulfur and variably enriched in bromine relative to chlorine. The interaction with water in the past is indicated by the chemical features in rocks and soils at this site.
Asunto(s)
Marte , Partículas alfa , Bromo , Cloro , Elementos Químicos , Medio Ambiente Extraterrestre , Compuestos Férricos , Sedimentos Geológicos , Hierro , Magnesio , Minerales , Silicatos , Nave Espacial , Espectrometría por Rayos X , Sulfatos , Azufre , AguaRESUMEN
The alpha particle x-ray spectrometer on the Spirit rover determined major and minor elements of soils and rocks in Gusev crater in order to unravel the crustal evolution of planet Mars. The composition of soils is similar to those at previous landing sites, as a result of global mixing and distribution by dust storms. Rocks (fresh surfaces exposed by the rock abrasion tool) resemble volcanic rocks of primitive basaltic composition with low intrinsic potassium contents. High abundance of bromine (up to 170 parts per million) in rocks may indicate the alteration of surfaces formed during a past period of aqueous activity in Gusev crater.
Asunto(s)
Elementos Químicos , Marte , Partículas alfa , Bromo , Evolución Planetaria , Medio Ambiente Extraterrestre , Sedimentos Geológicos , Potasio , Análisis Espectral , AguaRESUMEN
The alpha proton x-ray spectrometer (APXS) on board the rover of the Mars Pathfinder mission measured the chemical composition of six soils and five rocks at the Ares Vallis landing site. The soil analyses show similarity to those determined by the Viking missions. The analyzed rocks were partially covered by dust but otherwise compositionally similar to each other. They are unexpectedly high in silica and potassium, but low in magnesium compared to martian soils and martian meteorites. The analyzed rocks are similar in composition to terrestrial andesites and close to the mean composition of Earth's crust. Addition of a mafic component and reaction products of volcanic gases to the local rock material is necessary to explain the soil composition.