Martian dust

Fig. 3.23 Left-. Calculated relationship between the thickness of an alteration rind and/or dust coating on a rock and the amount of 15.0-keV radiation absorbed in the rind/coating for densities of 0.4, 2.4, and 4.0 g cm [57]. The bulk chemical composition of basaltic rock was used in the calculations, and the 15.0 keV energy is approximately the energy of the 14.4 keV y-ray used in the Mossbauer experiment. The stippled area between densities of 2.4 and 4.0 g cm is the region for dry bulk densities of terrestrial andesitic and basaltic rocks [58]. The stippled area between densities of 0.1 and 0.4 g cm approximates the range of densities possible for Martian dust. The density of 0.1 g cm is the density of basaltic dust deposited by air fall in laboratory experiments [59]. Right Measured spectra obtained on layered laboratory samples and the corresponding simulated spectra, from top to bottom 14.4 keV measured (m) 14.4 keV simulated (s) 6.4 keV measured (m) and 6.4 keV simulated (s). All measurements were performed at room temperature. Zero velocity is referenced with respect to metallic iron foil. Simulation was performed using a Monte Carlo-based program (see [56])...

Jurewicz A J G, Forney L, Bomba J, Vicker D, Jones S, Yen A, Clark B, Gamber T, Leshin L A, Richardson R, Sharpe T, Thie- mens M, Thornton J M, Zolensky M (2002) Investigating the use of aerogel collectors for the SCIM martian dust sample return. Lunar Planetary Sci. Conf. XXXIII, Lunar Planetary In- stitute, Houston, TX., 2002 Abstract 1703... 

Toon, O. B., Pollack, J. B., Sagan, C. (1977). Physical properties of the particles comprising the Martian dust storm of 1971-1972. Icarus, 30, 663-96. 

Martian dust storms and climate change were studied by Leovy, 1986 [199]. Seasonal cycles of dust, carbon dioxide and water in connection with astronomical changes (tilt of obliquity, impacts) have to be considered for modeling the martian climate. 

Leovy, C.B. Martian dust storms and climate change. In Carr, M., James, P., Conway, L., Pepin, R., PoUack, J. (eds.) MECA Workshop on the Evolution of the Mtirtian Atmosphere. A Lunar and Pianetary Institute Workshop held in Honolulu, Hawaii, August 9-10, 1985. LPI Technical Report 86-07, p. 26 (1986). Lunar and Planetary Institute, 3303 NASA Road... 

When considering how the evolution of life could have come about, the seeding of terrestrial life by extraterrestrial bacterial spores traveling through space (panspermia) deserves mention. Much is said about the possibility of some form of life on other planets, including Mars or more distant celestial bodies. Is it possible for some remnants of bacterial life, enclosed in a protective coat of rock dust, to have traveled enormous distances, staying dormant at the extremely low temperature of space and even surviving deadly radiation The spore may be neither alive nor completely dead, and even after billions of years it could have an infinitesimal chance to reach a planet where liquid water could restart its life. Is this science fiction or a real possibility We don t know. Around the turn of the twentieth century Svante Arrhenius (Nobel Prize in chemistry 1903) developed this theory in more detail. There was much recent excitement about claimed fossil bacterial remains in a Martian meteorite recovered from Antarctica (not since... 

The extensive layered sediments at the south pole, which contain water ice, will provide information on climatic variations. The subsurface sounding radar instrument SHARAD (Shallow Radar) on board the Mars Reconnaissance Orbiter carried out a detailed cartographic study of the subsurface at the Martian south pole. The data indicate that the sediments there have been subjected to considerable erosion (R. Seu et al 2007). The density of the material deposited at the Martian south pole was calculated by M. T. Zuber and co-workers by combining data from the gravitational field with those from various instruments on board the Mars Orbiter, they obtained a value of 1,200 kg/m3. This value corresponds to that calculated for water ice containing about 15% dust (Zuber et al 2007). 

The layers of sediment at the Martian south pole do not consist of pure ice they are interspersed by layers of dust. The latest data were obtained by the Mars Advanced Radar for Subsurface and Ionospheric Sounding apparatus (MARSIS) on board the Mars Express Orbiter. The radar waves from the instrument pass through the ice layers until they reach the base layer, which can be at a depth of up to 3.7 km. The distribution of the ice at the south pole is asymmetric, and its total volume has been estimated to be 1.6 x 106km3 this corresponds to an amount of water which would cover the whole planet with a layer 11 metres deep (Plaut et al., 2007). 

Alkalis versus silica diagram used for geochemical classification of volcanic rocks. Martian meteorites, Gusev crater rocks and soils analyzed by the Spirit rover, and Bounce Rock analyzed by the Opportunity rover generally plot in the field of basalts, as does the average Mars Odyssey GRS analysis. Compositions derived from TES spectra (Surface Types 1 and 2) and the Mars Pathfinder dust-free rock plot in the basaltic andesite and andesite fields. After McSween et at. (2009). 

However, these meteorites are depleted in aluminum relative to terrestrial rocks, a characteristic shared by martian soils and the Mars Pathfinder dust-free rock (Figure 5). Ratios of volatile to refractory elements (e.g., K/La) are constant but higher than in terrestrial or lunar rocks (Figure 6). 

Figure 11 Chemical classification of martian volcanic rocks. Squares show basaltic materials in the southern highlands (surface 1) and andesitic materials in the northern lowlands (surface 2), derived from deconvolved TES spectra from Mars Global Surveyor (Hamilton et al., 2001). Analyzed compositions of the Mars Pathfinder dust-free rock (Wanke et al., 2001) and martian meteorites (basaltic shergottites are filled circles and nakhlites are...

Compositions of the pervasive layered deposits seen in Mars Global Surveyor imagery (Malin and Edgett, 2000) have not been measured directly. However, TES spectra, which are dominated by sand-sized particles, indicate that igneous minerals (pyroxenes and plagioclase) are abundant on the martian surface. Quartz, which should be readily detectable in TES spectra, has not been observed. Deconvolutions of the spectra of soils and dust are dominated by framework silicates, either plagioclase or zeolites (Bandfield and Smith, 2003 McSween et aL, 2003). 

McSween H. Y. and Keil K. (2000) Mixing relationships in the martian regolith and the composition of globally homogeneous dust. Geochim. Cosmochim. Acta 64, 2155-2166. 

McSween H. Y., Hamilton V. E., and Hapke B. W. (2003) Mineralogy of martian atmospheric dust inferred from spectral deconvolution of MGS TES and Mariner 9 IRIS data. Lunar Planet Sci. XXXIV, 1233. The Lunar and Planetary Instimte, Houston (CD-ROM). 

Pathfinder), 4000 km apart in the northern hemisphere gave similar basaltic compositions for the fine-grained soils that were analyzed the fine material will contain a significant component from the ancient cratered terrain that dominates the southern hemisphere, where most of the global dust storms originate. However, no component more siliceous than basalt appears in the Martian compositions. At the Pathfinder site, more siliceous rock... 

Whether formed from acetylene or from some other sources, PAHs are widely distributed in the solar system. As mentioned earlier, PAHs are found in the atmospheres of Jupiter and Titan [37]. They have also been detected in meteorites, including the Martian meteorite Allan Hills 84001 [43], in interplanetary dust [44], and in circumstellar graphite grains [45]. The ubiquity of these complex organic structures and their stability under extreme conditions is a significant factor in discussions of the origin of life on earth and the possibility of its existence elsewhere. 

This chapter provides an overview of available noble gas data for solar system bodies apart from the Earth, Mars, and asteroids. Besides the Sun, the Moon, and the giant planets, we will also discuss data for the tenuous atmospheres of Mercury and the Moon, comets, interplanetary dust particles and elementary particles in the interplanetary medium and beyond. In addition, we summarize the scarce data base for the Venusian atmosphere. The extensive meteorite data from Mars and asteroidal sources are discussed in chapters in this volume by Ott (2002), Swindle (2002a,b) and Wieler (2002). Data from the Venusian and Martian atmospheres are discussed in more detail in chapters by Pepin and Porcelli (2002) and Swindle (2002b). Where appropriate, we will also present some data for other highly volatile elements such as H or N. 

Harvey RP (2003) The origin and significance of Antarctic meteorites. Chemie der Erde 63 93-147 Harvey RP, Maurette M (1990) The best cosmic dust source in the world The origin and significance of the Walcott Neve, Antarctica, micrometeorites. Lunar and Planetary Science Conference, vol. 21—. LPI, Houston, TX, pp 569-578 Harvey RP, McSween HY Jr (1996) A possible high-tempera-ture origin for the carbonates in the martian meteorite ALH 84001. Nature 382 49-51... 

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