Identification of iron in Earth analogues of Martian phyllosilicates using visible reflectance spectroscopy: Spectral derivatives and color parameters

A range of phyllosilicate compositions have been detected spectroscopically on Mars, but the largest fraction by far corresponds to clay minerals rich in Fe and Mg. Given that most of our understanding of Martian clays comes from remote sensing data, it is critically important to explore the details of how compositional variation affects spectral features of phyllosilicates. The greatest efforts have focused so far on near-infrared (NIR) spectroscopy. Recently, ambiguities have been detected in the NIR spectra of 2:1 phyllosilicates with intermediate FeeMg content that preclude mineral and chemical discrimination. Such ambiguities highlight the relevance of exploring the visible spectral range as a complementary tool to characterize Martian phyllosilicates precisely. This article reports the investigation of laboratory reflectance spectra (330–800 nm) from 34 Earth analogues of Martian phyllosilicates with a wide range of MgeFe composition, including nontronite, celadonite and saponite end-members, as well as interstratified glauconite-nontronite, talc-nontronite, and talc-saponite. The spectra indicated the presence of Fe(III) by absorption modulations and a decrease in total reflectance, especially in samples with tetrahedral Fe(III). Absorption bands at 370 and 420 nm were diagnostic of octahedrically and tetrahedrally coordinated Fe(III), respectively. Band amplitudes in the second derivative of the Kubelka-Munk function correlated positively with Fe(III) content (R2 > 0.8). Standard color analyses of the visible reflectance spectra under the CIE illuminant D65 indicated that the CIELAB color parameter a*10 was positively correlated with tetrahedral Fe(III), b*10 was positively correlated with octahedral Fe(III), and L*10 was negatively correlated with Fe(III) in both structural sites. Because Fe(II) was in relatively low amount, it did not provide clear spectral evidence. Multiple regression models using the amplitude of the diagnostic absorption bands predicted well absolute Fe content in the phyllosilicates (R2=0.89) and the ratio Fe/(Fe+Mg+Al) (R2=0.84). CIELAB color parameters improved the prediction of total Fe (R2=0.92) and the ratio Fe/(Fe+Mg+Al) (R2=0.93). Application of these analyses to Martian data has challenges set by Fe oxide dust coating and spatial and spectral resolution. However, these results mark an avenue to develop testable tools using visible-wavelength spectral data from both satellite and lander probes to help establishing Fe content and mineral identification of Martian phyllosilicates

Hydrothermal sediment alteration at a seafloor vent field: Grimsey Graben, Tjörnes Fracture Zone, north of Iceland

An active seafloor hydrothermal system subjects the background sediments of the Grimsey Graben (Tjörnes Fracture Zone) to alteration that produces dissolution of the primary volcaniclastic matrix and replacement/precipitation of sulfides, sulfates, oxides, oxyhydroxides, carbonates and phyllosilicates. Three types of hydrothermal alteration of the sediment are defined on the basis of the dominant hydrothermal phyllosilicate formed: smectite, kaolinite, chlorite. The most common alteration is near‐total conversion of the volcaniclastic material to smectite (95–116°C). The dominant smectite in the deepest sediments sampled is beidellite, which is replaced by montmorillonite and an intimate mixture of di‐ and tri‐octahedral smectite up core. This gradual vertical change in smectite composition suggests an increase in the Mg supply upward, the result of sediment alteration by the ascending hydrothermal fluids mixing with descending seawater. The vertical sequence kaolinite → kaolinite‐smectite mixed‐layer → smectite from bottom to top of a core, as well as the distinct zonation across the veins (kaolinite in the central zone → kaolinite‐smectite in the rim), suggests hydrothermal transformation of the initially formed smectite to kaolinite through kaolinite‐smectite mixed‐layer (150–160°C). The cause of this transformation might have been an evolution of the fluids toward a slightly acidic pH or a relative increase in the Al concentration. Minor amounts of chamosite fill thin veins in the deepest sections of some cores. The gradual change from background clinochlore to chamosite across the veins suggests that chamosite replaces clinochlore as Fe is made available from hydrothermal dissolution of detrital Fe‐containing minerals. The internal textures, REE distribution patterns and the mode of occurrence of another magnesian phyllosilicate, kerolite, suggest that this mineral is the primary precipitate in the hydrothermal chimneys rather than an alteration product in the sediment. Kerolite precipitated after and grew on anhydrite in the chimneys. Oxygen isotope ratios are interpreted to reflect precipitation of kerolite at temperatures of 302° to 336°C. It accumulated in the hydrothermal mounds following the collapse of the chimneys and subsequent dissolution of anhydrite, thereby forming highly permeable aquifer layers underlying the vent field. Some kerolite was redeposited in the near vent field sediments by turbidity flows. The altered sediments are depleted in Mn, Rb and Sr, and enriched in U, Mo, Pb, Ba, As, Bi, Sb, Ag, Tl and Ga, as a result of leaching and precipitation, respectively. Conservative elements (Ti, Zr, Hf, Sc, Cr, Nb and Sn) are depleted or enriched in the altered sediments because of passive (precipitation or leaching of other phases) rather than active (because of their mobility) processes

Effects of Iodine upon the Structure and Function of Mitochondria

Abstract The influence of iodine in its positive and negative monovalent form upon the oxygen consumption in euthyroid and thyroidectomized rats and the oxidative phosphorylation in liver mitochondria isolated from both groups of animals, as well as the spontaneous swelling and total ATPase activity of mitochondria have been studied. It was established that the administration of ICI increased the oxygen consumption of normal and thyroidectomized rats while under the same conditions no effect was found with NaI .IBr stimulated the oxygen consumption in vitro in liver mitochondria isolated both from normal and thyroidectomized rats and decreased the P/O ratio while NaI had no effect. I2 and IBr increased the swelling and inhibited the ATPase activity of isolated rat liver mitochondria, while these effects were not observed when KI was used. The thyroidstatic 1-methyl-2-mercaptoimidazol decreased the stimulating effect of iodine upon the swelling of mitochondria and to a certain extent lowered its inhibiting effect upon the ATPase activity. It is concluded that iodine in its positive monovalent form has a thyroxine-like effect upon the structure and function of isolated rat liver mitochondria, as well as in vivo upon the respiration of euthyroid and thyroidectomized rats

Records export, transfer and ingest recommendations and SIP Creation Tools

This report describes a software deliverable as it delivers a number of E-ARK tools: • ERMS Export Module (a tool for exporting records and their metadata from ERMS in a controlled manner); • Database Preservation Toolkit (a tool for exporting relational databases as SIARD 2.0 or other formats); • ESSArch Tools for Producer (a tool for SIP creation); • ESSArch Tools for Archive (a tool for SIP ingestion); • RODA-in (a tool for SIP creation); • Universal Archiving Module (a tool for SIP creation). In addition, an overview of Pre-Ingest and Ingest processes will be provided by this report which will help to understand the tools and their use

A Two-Step K-Ar Experiment on Mars: Dating the Diagenetic Formation of Jarosite from Amazonian Groundwaters

Following K-Ar dating of a mudstone and a sandstone, a third sample has been dated by the Curiosity rover exploring Gale Crater. The Mojave 2 mudstone, which contains relatively abundant jarosite, yielded a young K-Ar bulk age of 2.57 ± 0.39 Ga (1σ precision). A two-step heating experiment was implemented in an effort to resolve the K-Ar ages of primary and secondary mineralogical components within the sample. This technique involves measurement of 40Ar released in low-temperature (500°C) and high-temperature (930°C) steps, and a model of the potassium distribution within the mineralogical components of the sample. Using this method, the high-temperature step yields a K-Ar model age of 4.07 ± 0.63 Ga associated with detrital plagioclase, compatible with the age obtained on the Cumberland mudstone by Curiosity. The low-temperature step, associated with jarosite mixed with K-bearing evaporites and/or phyllosilicates, gave a youthful K-Ar model age of 2.12 ± 0.36 Ga. The interpretation of this result is complicated by the potential for argon loss after mineral formation. Comparison with the results on Cumberland and previously published constraints on argon retentivity of the individual phases likely to be present suggests that the formation age of the secondary materials, correcting for plausible extents of argon loss, is still less than 3 Ga, suggesting post-3 Ga aqueous processes occurred in the sediments in Gale Crater. Such a result is inconsistent with K-bearing mineral formation in Gale Lake and instead suggests postdepositional fluid flow at a time after surface fluvial activity on Mars is thought to have largely ceased

The E-ARK Integrated Platform Reference Implementation

The report describes a set of software components that have been developed in order to realize the E-ARK Integrated Platform Reference Implementation Prototype for storing, searching, and accessing E-ARK Information Packages on a scalable infrastructure. The E-ARK Integrated Platform Reference Implementation Prototype integrates: (a) an Information Package creation and management system, (b) a repository for content search and access, and (c) a scalable storage and execution environment based on Apache Hadoop. The report focuses on the software components that have been individually developed and deployed on top of the core infrastructure components (Hadoop, Lily, SolR). This complements deliverable D6.1 which describes the set-up and configuration of the repository and indexing frameworks. This report accompanies a number of software development results which have been developed in order to realize the Integrated Platform Reference Implementation Prototype. Besides the individual software components, the report provides an overview of the overall system architecture, the integration approach and utilized interfaces

Quantitative X-ray diffraction phase analysis of poorly ordered nontronite clay in nickel laterites

Studies of the extraction of nickel from low-grade laterite ores require a much better quantitative understanding of the poorly ordered mineral phases present, including turbostratically disordered nontronite. Whole pattern refinements with nontronite X-ray diffraction data from a Western Australian nickel deposit (Bulong) using a nontronite lattice model (Pawley phase) with two space groups(P3 and C2/m) and a peaks phase group model were performed to improve the accuracy of quantitative X-ray diffraction of nickel laterite ore samples. Modifications were applied when building the new models to accommodate asymmetric peak shape and anisotropic peak broadening due to the turbostraticdisorder. Spherical harmonics were used as convolution factors to represent anisotropic crystal size and strain and asymmetric peak shape when using the lattice model. A peaks phase group model was also developed to fit the anisotropic peak broadening in the nontronite pattern. The quantitative resultsof the new Pawley phase and peaks phase group models were compared and verified with synthetic mixtures of nontronite, quartz and goethite simulating various West Australian laterite ore compositions. The models developed in this paper demonstrate adequate accuracy for quantification of nontronite in the synthesized reference materials and should be generally applicable toquantitative phase analysis of nontronite in nickel laterite ore samples

Differing molecular pathology of pancreatic adenocarcinoma in Egyptian and United States patients

Variations in genetic mutations in pancreatic carcinoma between different populations have not been studied extensively, especially in developing countries where pancreatic cancer is rare. We studied the molecular pathology of 44 pancreatic carcinomas from patients residing in a heavily polluted region in the Nile River delta and compared the findings with tumors from 44 United States (US) patients. We evaluated K-ras mutations in codon 12, p53 mutations in exons 5–8, and Gadd45a mutations in exons 1 and 4. Overall, rates of K-ras , p53 and Gadd45 mutations were not statistically different in tumors of patients from Egypt and the US (67.4 vs. 63.4%; 27.3 vs. 36.4% and 9.1 vs. 4.5%, respectively). However, there were distinct differences in the specific types of K-ras and p53 mutations between the 2 groups. In K-ras , G → T transversion mutation was more frequent in the tumors from Egypt than from the US (58.6 vs. 26.9%), whereas G → C transversion was detected in 26.9% of US tumors but none from Egypt ( p = 0.003). We also found a trend toward differences in the p53 exons in which mutations occurred, with higher frequency of exon 5 mutation and lower frequency of exon 6 mutation in Egyptian tumors. Logistic regression showed that K-ras G → T transversion mutations and p53 exon 6 mutations were predicted by the country of residence of the patients. Our study identifies that there are differences in the types of mutations found in tumors from pancreatic carcinoma patients in Egypt and the US, and suggests that environmental factors may explain these differences. © 2006 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/55779/1/21986_ftp.pd

Ancient hydrothermal seafloor deposits in Eridania basin on Mars

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/ licenses/by/4.0/. The file attached is the Published/publisher’s pdf version of the article

Subsurface hydrothermal processes and the bioenergetics of chemolithoautotrophy at the shallow-sea vents off Panarea Island (Italy)

The subsurface evolution of shallow-sea hydrothermal fluids is a function of many factors including fluid-mineral equilibria, phase separation, magmatic inputs, and mineral precipitation, all of which influence discharging fluid chemistry and consequently associated seafloor microbial communities. Shallow-sea vent systems, however, are understudied in this regard. In order to investigate subsurface processes in a shallow-sea hydrothermal vent, and determine how these physical and chemical parameters influence the metabolic potential of the microbial communities, three shallow-sea hydrothermal vents associated with Panarea Island (Italy) were characterized. Vent fluids, pore fluids and gases at the three sites were sampled and analyzed for major and minor elements, redox-sensitive compounds, free gas compositions, and strontium isotopes. The corresponding data were used to 1) describe the subsurface geochemical evolution of the fluids and 2) to evaluate the catabolic potential of 61 inorganic redox reactions for in situ microbial communities. Generally, the vent fluids can be hot (up to 135 °C), acidic (pH 1.9-5.7), and sulfidic (up to 2.5 mM H2S). Three distinct types of hydrothermal fluids were identified, each with higher temperatures and lower pH, Mg2 + and SO42 -, relative to seawater. Type 1 was consistently more saline than Type 2, and both were more saline than seawater. Type 3 fluids were similar to or slightly depleted in most major ions relative to seawater. End-member calculations of conservative elements indicate that Type 1 and Type 2 fluids are derived from two different sources, most likely 1) a deeper, higher salinity reservoir and 2) a shallower, lower salinity reservoir, respectively, in a layered hydrothermal system. The deeper reservoir records some of the highest end-member Cl concentrations to date, and developed as a result of recirculation of brine fluids with long term loss of steam and volatiles due to past phase separation. No strong evidence for ongoing phase separation is observed. Type 3 fluids are suggested to be mostly influenced by degassing of volatiles and subsequently dissolution of CO2, H2S, and other gases into the aqueous phase. Gibbs energies (ΔGr) of redox reactions that couple potential terminal electron acceptors (O2, NO3-, MnIV, FeIII, SO42 -, S0, CO2,) with potential electron donors (H2, NH4+, Fe2 +, Mn2 +, H2S, CH4) were evaluated at in situ temperatures and compositions for each site and by fluid type. When Gibbs energies of reaction are normalized per kilogram of hydrothermal fluid, sulfur oxidation reactions are the most exergonic, while the oxidation of Fe2 +, NH4+, CH4, and Mn2 + are moderately energy yielding. The energetics calculations indicate that the most robust microbial communities in the Panarea hot springs combine H2S from deep water-rock-gas interactions with O2 that is entrained via seawater mixing to fuel their activities, regardless of site location or fluid type