Key Role of Phosphorus in the Formation of the Iron Oxides in Mars Soils?

Torrent, J.; Barrón, Vidal

doi:10.1006/icar.2000.6408

Cited by 11 publications

(12 citation statements)

References 18 publications

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“…The uptake of phosphate then increased steadily to reach equilibrium at about 20 h, with slow sorption kinetics observed at longer times. Such slow sorption following initially rapid uptake of phosphate has been observed previously (e.g., Berner, 1973;Torrent and Barron, 2000) and interpreted as sorption to micro-pores or grooves and within aggregates (Willett et al, 1988;Strauss et al, 1997). Since the extent of slow kinetics depends on the crystallinity of minerals (Strauss et al, 1997), this effect is expected to be more pronounced in low crystalline ferrihydrite.…”

Section: °Cmentioning

confidence: 78%

“…doi:10. 1016/j.gca.2009.11.010 maghemite) depending on the solution pH, temperature and P/Fe ratio (Galvez et al, 1999;Torrent and Barron, 2000). The sorption of dissolved inorganic ortho-phosphate, PO 4 , to Fe-oxide-rich sediments can reduce the concentration of bio-available P and buffer dissolved PO 4 to growth-limiting concentrations (Blake et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

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Fractionation of oxygen isotopes in phosphate during its interactions with iron oxides

Jaisi

Blake

Kukkadapu

2010

Geochimica et Cosmochimica Acta

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Iron (III) oxides are ubiquitous in near-surface soils and sediments and interact strongly with dissolved phosphates via sorption, co-precipitation, mineral transformation and redox-cycling reactions. Iron oxide phases are thus, an important reservoir for dissolved phosphate, and phosphate bound to iron oxides may reflect dissolved phosphate sources as well as carry a history of the biogeochemical cycling of phosphorus (P). It has recently been demonstrated that dissolved inorganic phosphate (DIP) in rivers, lakes, estuaries and the open ocean can be used to distinguish different P sources and biological reaction pathways in the ratio of 18 O/ 16 O (d 18 O P ) in PO 4 3À . Here we present results of experimental studies aimed at determining whether non-biological interactions between dissolved inorganic phosphate and solid iron oxides involve fractionation of oxygen isotopes in PO 4 . Determination of such fractionations is critical to any interpretation of d 18 O P values of modern (e.g., hydrothermal iron oxide deposits, marine sediments, soils, groundwater systems) to ancient and extraterrestrial samples (e.g., BIF's, Martian soils). Batch sorption experiments were performed using varied concentrations of synthetic ferrihydrite and isotopically-labeled dissolved ortho-phosphate at temperatures ranging from 4 to 95°C. Mineral transformations and morphological changes were determined by X-Ray, Mö ssbauer spectroscopy and SEM image analyses.Our results show that isotopic fractionation between sorbed and aqueous phosphate occurs during the early phase of sorption with isotopically-light phosphate (P 16 O 4 ) preferentially incorporated into sorbed/solid phases. This fractionation showed negligible temperature-dependence and gradually decreased as a result of O-isotope exchange between sorbed and aqueousphase phosphate, to become insignificant at greater than $100 h of reaction. In high-temperature experiments, this exchange was very rapid resulting in negligible fractionation between sorbed and aqueous-phase phosphate at much shorter reaction times. Mineral transformation resulted in initial preferential desorption/loss of light phosphate (P 16 O 4 ) to solution. However, the continual exchange between sorbed and aqueous PO 4 , concomitant with this mineralogical transformation resulted again in negligible fractionation between aqueous and sorbed PO 4 at long reaction times (>2000 h). This finding is consistent with results obtained from natural marine samples. Therefore, 18 O values of dissolved phosphate (DIP) in sea water may be preserved during its sorption to iron-oxide minerals such as hydrothermal plume particles, making marine iron oxides a potential new proxy for dissolved phosphate in the oceans.

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Section: °Cmentioning

confidence: 78%

Section: Introductionmentioning

confidence: 99%

Fractionation of oxygen isotopes in phosphate during its interactions with iron oxides

Jaisi

Blake

Kukkadapu

2010

Geochimica et Cosmochimica Acta

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“…The possibility of maghemite being present at the surface of Mars is evidenced by analysis of magnetic dust in situ (Bertelsen et al, ). Since the magnetic properties of Martian dust and soil are presumed to be dictated, as on Earth, by magnetite and maghemite (Banin et al, ; Madsen et al, ; Morris et al, , ), the production of maghemite by vapor deposition on the surface of cooling lava flows provides an important alternative production mechanism to that of the thermal conversion of lepidocrocite via meteoritic impact (Banin et al, ; Morris et al, ) or its formation as a transient phase in the transformation of ferrihydrite to hematite in the presence of phosphate or other ligands capable of ligand exchange with Fe‐OH surface groups (Barron & Torrent, ; Cumplido et al, ; Torrent & Barrón, ).…”

Section: Discussionmentioning

confidence: 99%

Vapor‐Deposited Minerals Contributed to the Martian Surface During Magmatic Degassing

et al. 2019

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Martian magmas were likely enriched in S and Cl with respect to H2O. Exsolution of a vapor phase from these magmas and ascent of the gas bubbles through the magma plumbing system would have given rise to shallow magmas that were gas‐charged. Release and cooling of this gas from lava flows during eruption may have resulted in the addition of a significant amount of vapor‐deposited phases to the fines of the surface. Experiments were conducted to simulate degassing of gas‐charged lava flows and shallow intrusions in order to determine the nature of vapor‐deposited phases that may form through this process. The results indicate that magmatic gas may have contributed a large amount of Fe, S, and Cl to the Martian surface through the deposition of iron oxides (magnetite, maghemite, and hematite), chlorides (molysite, halite, and sylvite), sulfur, and sulfides (pyrrhotite and pyrite). Primary magmatic vapor‐deposited minerals may react during cooling to form a variety of secondary products, including iron oxychloride (FeOCl), akaganéite (Fe3+O (OH,Cl)), and jarosite (KFe3+3(OH)6(SO4)2). Vapor‐deposition does not transport significant amounts of Ca, Al, or Mg from the magma and hence, this process does not directly deposit Ca‐ or Mg‐sulfates.

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“…For example, chloride in acidic solutions can promote formation of spherical hematite particles with sizes of ∼0.05–0.5 μm (Sugimoto et al., 1998). Phosphate, which has high concentrations (∼3 g/kg) in Martian soils (e.g., Dreibus et al., 1999), favors hematite over goethite formation (Gálvez et al., 1999; Ren et al., 2020; Torrent & Barrón, 2000). Alteration of jarosite (KFe 3 (SO 4 ) 2 (OH) 6 ) to hematite under low temperature acidic conditions is a further mechanism for nanophase hematite formation on Mars, which suggests a transient period with liquid water at Meridiani Planum (Barrón et al., 2006).…”

Section: Hematite Occurrences and Formation On Earth And Marsmentioning

confidence: 99%

“…This pathway has been cited as a possible explanation for magnetic enhancement of Chinese paleosol/loess samples during heating at ∼280°C (Deng et al., 2001). It is also considered to be the dominant mode of maghemite and hematite formation in Martian soils (Torrent & Barrón, 2000). Gendler et al.…”

Section: Hematite Occurrences and Formation On Earth And Marsmentioning

confidence: 99%

The Magnetic and Color Reflectance Properties of Hematite: From Earth to Mars

Jiang

Liu

Roberts

et al. 2022

Reviews of Geophysics

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Hematite is a canted antiferromagnet with reddish color that occurs widely on Earth and Mars. Identification and quantification of hematite is conveniently achieved through its magnetic and color properties. Hematite characteristics and content are indispensable ingredients in studies of the iron cycle, paleoenvironmental evolution, paleogeographic reconstructions, and comparative planetology (e.g., Mars). However, the existing magnetic and color reflectance property framework for hematite is based largely on stoichiometric hematite and tends to neglect the effects of cation substitution, which occurs widely in natural hematite and influences the physical properties of hematite. Thus, magnetic parameters for stoichiometric hematite are insufficient for complete analysis of many natural hematite occurrences and can lead to ambiguous geological interpretations. Remagnetization, which occurs pervasively in red beds, is another ticklish problem involving hematite. Understanding red bed remagnetization requires investigation of hematite's formation and remanence recording mechanisms. We elaborate on the influence of cation substitution on the magnetic and color spectral properties of hematite, and on identifying hematite and quantifying its content in soils and sediments. Studies of remagnetization mechanisms are discussed, and we summarize methods to discriminate between primary and secondary remanences carried by hematite in natural samples to aid primary remanence extraction in partially remagnetized red beds. Although there remain unknown properties and unresolved issues that require future work, recognition of the properties of cation‐substituted hematite and remagnetization mechanisms for hematite will aid identification and interpretation of the magnetic signals that it carries, which is environmentally important and responsible for magnetic signals on Earth and Mars.

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Key Role of Phosphorus in the Formation of the Iron Oxides in Mars Soils?

Cited by 11 publications

References 18 publications

Fractionation of oxygen isotopes in phosphate during its interactions with iron oxides

Fractionation of oxygen isotopes in phosphate during its interactions with iron oxides

Vapor‐Deposited Minerals Contributed to the Martian Surface During Magmatic Degassing

The Magnetic and Color Reflectance Properties of Hematite: From Earth to Mars

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