Jarosite as an indicator of water-limited chemical weathering on Mars

Madden, M. E. Elwood; Bodnar, Robert J.; Rimstidt, J. Donald

doi:10.1038/nature02971

Cited by 252 publications

(86 citation statements)

References 25 publications

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“…Noachian and Hesperian terrains are well preserved and widespread on Mars (Michalski et al, 2013). Jarosite is preserved for geological timescales only in extremely arid conditions, and the persistence of jarosite on Mars is testament to the planet's extreme surface aridity in post-Hesperian times (Elwood Madden et al, 2004). …”

Section: Introductionmentioning

confidence: 99%

Sulfate Minerals: A Problem for the Detection of Organic Compounds on Mars?

et al. 2015

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The search for in situ organic matter on Mars involves encounters with minerals and requires an understanding of their influence on lander and rover experiments. Inorganic host materials can be helpful by aiding the preservation of organic compounds or unhelpful by causing the destruction of organic matter during thermal extraction steps. Perchlorates are recognized as confounding minerals for thermal degradation studies. On heating, perchlorates can decompose to produce oxygen, which then oxidizes organic matter. Other common minerals on Mars, such as sulfates, may also produce oxygen upon thermal decay, presenting an additional complication. Different sulfate species decompose within a large range of temperatures. We performed a series of experiments on a sample containing the ferric sulfate jarosite. The sulfate ions within jarosite break down from 500°C. Carbon dioxide detected during heating of the sample was attributed to oxidation of organic matter. A laboratory standard of ferric sulfate hydrate released sulfur dioxide from 550°C, and an oxygen peak was detected in the products. Calcium sulfate did not decompose below 1000°C. Oxygen released from sulfate minerals may have already affected organic compound detection during in situ thermal experiments on Mars missions. A combination of preliminary mineralogical analyses and suitably selected pyrolysis temperatures may increase future success in the search for past or present life on Mars. Key Words: Mars—Life detection—Geochemistry—Organic matter—Jarosite. Astrobiology 15, 247–258.

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Section: Introductionmentioning

confidence: 99%

Sulfate Minerals: A Problem for the Detection of Organic Compounds on Mars?

et al. 2015

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“…However, such extrapolations depend upon the pH of weathering (Fig. 2) and such pH is poorly constrained on Mars: weathering pH may have been very acidic (Elwood Madden et al, 2004;Klingelhofer et al, 2004;Tosca et al, 2004;Hurowitz et al, 2006) or close to neutral Bibring et al, 2006). The pH of a weathering solution strongly affects relative mineral persistences (Fig.…”

Section: Mineral Persistencementioning

confidence: 99%

Basalt weathering rates on Earth and the duration of liquid water on the plains of Gusev Crater, Mars

Hausrath

Navarre‐Sitchler

Sak

et al. 2008

Geol

116

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Where Martian rocks have been exposed to liquid water, chemistry versus depth profiles could elucidate both Martian climate history and potential for life. The persistence of primary minerals in weathered profiles constrains the exposure time to liquid water: on Earth, mineral persistence times range from ~10 ka (olivine) to ~250 ka (glass) to ~1Ma (pyroxene) to ~5Ma (plagioclase). Such persistence times suggest mineral persistence minima on Mars. However, Martian solutions may have been more acidic than on Earth. Relative mineral weathering rates observed for basalt in Svalbard (Norway) and Costa Rica demonstrate that laboratory pH trends can be used to estimate exposure to liquid water both qualitatively (mineral absence or presence) and quantitatively (using reactive transport models). Qualitatively, if the Martian solution pH > ~2, glass should persist longer than olivine; therefore, persistence of glass may be a pHindicator. With evidence for the pH of weathering, the reactive transport code CrunchFlow can quantitatively calculate the minimum duration of exposure to liquid water consistent with a chemical profile. For the profile measured on the surface of Humphrey in Gusev Crater, the minimum exposure time is 22 ka. If correct, this estimate is consistent with short-term, episodic alteration accompanied by ongoing surface erosion. More of these depth profiles should be measured to illuminate the weathering history of Mars.

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“…(http://www.news.cornell.edu/releases/rover/Mars.jarosite.html) Recent studies have identified iron sulphate minerals on Mars [19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

NIR spectroscopy of selected iron(II) and iron(III) sulphates

Frost

Wills

Martens

et al. 2005

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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A problem exists when closely related minerals are found in paragenetic relationships. The identification of such minerals cannot be undertaken by normal techniques such as X-ray diffraction. Vibrational spectroscopic techniques may be applicable especially when microtechniques or fibre-optic techniques are used. NIR spectroscopy is one technique which can be used for the identification of these paragenetically related minerals and has been applied to the study of selected iron(II) and iron(III) sulphates. The Near-IR spectral regions may be conveniently divided into four regions (a) the high wavenumber region > 7500 cm -1 (b) the high wavenumber region between 6400 and 7400 cm -1 attributed to the first overtone of the fundamental hydroxyl stretching mode (c) the 5500-6300 cm -1 region attributed to water combination modes of the hydroxyl fundamentals of water, and (d) the 4000-5500 cm -1 region attributed to the combination of the stretching and deformation modes of the iron(II) and iron(III) sulphates. The minerals containing iron(II) show a strong, broad band with splitting, around 11000-8000 cm -1 attributed to 5 T 2g → 5 E g transition. This shows the ferrous ion has distorted octahedral coordination in some of these sulphate minerals. For each of these regions, the minerals show distinctive spectra which enable their identification and characterisation. NIR spectroscopy is a less used technique which has great application for the study of minerals, particularly minerals which have hydrogen in the structure either as hydroxyl units or as water bonded to the cation as is the case for iron(II) and iron(III) sulphates. The study of minerals on planets is topical and NIR spectroscopy provides a rapid technique for the distinction and identification of iron(II) and iron(III) sulphates minerals.

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Jarosite as an indicator of water-limited chemical weathering on Mars

Cited by 252 publications

References 25 publications

Sulfate Minerals: A Problem for the Detection of Organic Compounds on Mars?

Sulfate Minerals: A Problem for the Detection of Organic Compounds on Mars?

Basalt weathering rates on Earth and the duration of liquid water on the plains of Gusev Crater, Mars

NIR spectroscopy of selected iron(II) and iron(III) sulphates

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