Effects of iron oxide coatings on the mobility and retardation of U(VI) in water saturated media

A new spectrophotometric interpretation of the influence of organic matter, iron oxides and moisture on the soil color of the Ste-Sophie sand and the Ste-Rosalie clay is reported. The method is based on calculation of the area ratio of the reflected (area under the reflectance curve) against the absorbed (area over the reflectance curve). The higher the ratio the lighter is the soil. After treatment to remove organic matter and iron oxide coatings, both soils presented colors significantly lighter than those observed in untreated soils. Organic matter and amorphous iron oxide contributed for 78% and 64% of the color in the Ste-Sophie sand and in the Ste-Rosalie clay, respectively. Moisture tends to mask the effects of organic matter and iron oxides on soil color. Air-dried soils when compared to moistened soils were lighter in color.

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Changes in the optical properties of thin iron oxide coatings during etching

Journal of Applied Spectroscopy ◽

10.1007/bf00615867 ◽

1975 ◽

Vol 23 (5) ◽

pp. 1509-1511

Author(s):

Yu. I. Kol'tsov

Keyword(s):

Optical Properties ◽

Iron Oxide ◽

Oxide Coatings ◽

Iron Oxide Coatings

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Surface characteristics and wear performance of laser surface engineered iron oxide coatings on cast aluminium alloy

Materials Science and Technology ◽

10.1179/026708302225004892 ◽

2002 ◽

Vol 18 (9) ◽

pp. 1036-1040 ◽

Cited By ~ 4

Author(s):

A. Dasari ◽

S. Nayak ◽

R. D. K. Misra ◽

O. O. Popoola ◽

N. B. Dahotre

Keyword(s):

Iron Oxide ◽

Aluminium Alloy ◽

Surface Characteristics ◽

Laser Surface ◽

Oxide Coatings ◽

Wear Performance ◽

Cast Aluminium ◽

Iron Oxide Coatings

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Carbonate rocks in the Mojave Desert as an analogue for Martian carbonates

International Journal of Astrobiology ◽

10.1017/s1473550411000206 ◽

2011 ◽

Vol 10 (4) ◽

pp. 349-358 ◽

Cited By ~ 22

Author(s):

Janice L. Bishop ◽

Rachel T. Schelble ◽

Christopher P. McKay ◽

Adrian J. Brown ◽

Kaysea A. Perry

Keyword(s):

Iron Oxide ◽

Mojave Desert ◽

Carbonate Rocks ◽

Thermal Emission ◽

Soil Environment ◽

X Ray Diffraction ◽

Oxide Coatings ◽

Imaging Spectrometer ◽

Iron Oxide Coatings ◽

Rock Coatings

AbstractCarbonate rocks in the Mojave Desert are presented as potential analogues for the carbonates on Mars. Rocks collected from the Little Red Hill site contain iron oxide-bearing coatings that greatly suppress the spectral features due to carbonate of the underlying material and impart a spectral slope. The Mojave Desert was formerly a lush pedogenic soil environment that, over time, transformed into the current arid climate with abundant rock varnish. One niche for microbes in the current desolate environment is inside and underneath the rocks where the microbes profit from solar protection by the iron oxide rock coatings. Carbonates were long predicted to be present on Mars and have recently been detected by instruments on Phoenix and MER and using hyperspectral orbiters such as the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), the Planetary Fourier Spectrometer (PFS) and the Thermal Emission Spectrometer (TES). We describe here the results of a study of carbonate rocks from the Little Red Hill site of the Mojave Desert that includes X-ray diffraction (XRD), chemistry and visible-infrared reflectance spectroscopy. Coatings on the carbonate rocks greatly reduced the strength of the carbonate bands and caused changes in the shape of some bands. We compare these data with a carbonate outcrop at Nili Fossae, Mars. If microbes once inhabited Mars, similar carbonate rocks with iron oxide coatings could have provided a UV-protected niche there as well. Thus, analysis of carbonate-bearing regions on Mars by future landers would be useful sites to search for biosignatures.

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