Capacity of Chlorate to Oxidize Ferrous Iron: Implications for Iron Oxide Formation on Mars

Chlorate is an important Cl-bearing species and a strong potential Fe(II) oxidant on Mars. Since the amount of oxychlorine species (perchlorate and chlorate) detected on Mars is limited (<~1 wt.%), the effectiveness of chlorate to produce iron oxides depends heavily on its oxidizing capacity. Decomposition of chlorate or intermediates produced during its reduction, before reaction with Fe(II) would decrease its effective capacity as an oxidant. We thus evaluated the capacity of chlorate to produce Fe(III) minerals in Mars-relevant fluids, via oxidation of dissolved Fe(II). Each chlorate ion can oxidize 6 Fe(II) ions under all conditions investigated. Mass balance demonstrated that 1 wt.% chlorate (as ClO3−) could produce approximately 6 to 12 wt.% Fe(III) or mixed valent mineral products, with the amount varying with the formula of the precipitating phase. The mineral products are primarily determined by the fluid type (chloride- or sulfate-rich), the solution pH, and the rate of Fe(II) oxidation. The pH at the time of initial mineral nucleation and the amount of residual dissolved Fe(II) in the system exert important additional controls on the final mineralogy. Subsequent diagenetic transformation of these phases would yield 5.7 wt.% hematite per wt.% of chlorate reacted, providing a quantitative constraint on the capacity of chlorate to generate iron oxides on Mars.

Major Sedimentary facies of the Miocene Formations and their Relation with Oil Production in the Central Euphrates depression: السحنات الرسوبية الرئيسة في تشكيلات الميوسين وعلاقتها بإنتاج النفط في منخفض الفرات المركزي

This research Deals with the identification of the major rocky facies of the Miocene Sedimentary formations in the central Euphrates depression, The purpose is determining the nature of these facies, their components, their spread, reservoir properties and their role in the generation and storage of oil and natural hydrocarbons. To achieve this, the methodology of the petrological study was applied to 60 Cores from the deep drilling samples of the Al-Mahash oilfields, which underwent chemical reactions with acids and reagents to determine the initial mineral structure of the rock, physical experiments and petrophysical measurements to determine the severity and porosity, and microscopic petrological study (by polarized microscope) done by using 248 microscopic rocky sections. The results were presented and recorded in composite records. The study showed the presence of eight major sedimentary facies in the Miocene formations, in the central Euphrates depression, which are: the calcareous facies, dolomitic calcareous, dolomitic, calcareous affluent of gypsum and anhydrite, evaporative, marl and Argillaceous calcareous and Argillaceous facies. The study also showed the role of the rocky facies in generating, covering and storing the natural hydrocarbons. reservoir carbonate facies accounted about 29% of the general lithological column of the Miocene formations, and concentrated in Jeribe and Transition zone Formations. Total porosity values ​​reached 30% in some highly cleft dolomite levels. The hydrocarbon generation capability was limited to a few sparse thicknesses, for some organic Argillaceous and calcareous deposits, concentrated at the bottom of jeribe and Euphrates formations. The nature of the rocky coverings of the reservoir was defined, composed of evaporators, by a thickness of about 37% of the general lithological column, which have a little presence in the upper levels of Debbane, Jeribe and Transition zone formations, and great abundance in the Lower Fars formation. Very limited horizontal changings in the facies and thickness of the Miocene sedimentary formations were observed along the field, , by correlation between the lithological columns. The correlation showed the effect of these changings on the generation, storage and production of oil and hydrocarbons in the Miocene sediments.

Mapping ice formation to mineral-surface topography using a micro mixing chamber with video and atomic-force microscopy

We developed a method for examining ice formation on solid materials under cloud-like conditions. Our experimental approach couples video-rate optical microscopy of ice formation with high-resolution atomic force microscopy (AFM) of the initial mineral surface. We demonstrate how colocating stitched AFM images with video microscopy can be used to relate the likelihood of ice formation to nanoscale properties of a mineral substrate, e.g., the abundance of surface steps of a certain height. We also discuss the potential of this setup for future iterative investigations of the properties of ice nucleation sites on materials.

345 Comparison of multiple trace mineral products provided to beef cattle as injectable, oral drench, oral paste, or bolus

To determine the effect of various trace mineral-containing products on trace mineral status of cattle 56 Angus-cross steers (303 ± 15 kg; n = 8 per treatment) were blocked by BW and administered a trace mineral treatment on d-0: injectable saline (CON), injectable Multimin®90 (ITM), MineralMax drench (MMD), MineralMax paste (MMP), Starting Fluid Drench (SFD), Se365 bolus (Se365), or Reloader250 bolus (Rel250). Steers received a common diet (silage-based d 0–49; corn-based d 50–122) via bunks capable of measuring individual feed disappearance. Plasma (0, 8, 24, and 48-h) and liver (-7, 2, 15, 29, 49, 65, 91, and 120-d) samples were obtained for analysis of Cu, Mn, Se, and Zn. Data were analyzed as repeated measures with effects of treatment, time, and treatment×time, with initial mineral concentration as covariate. Plasma Zn, Mn, and Se concentrations were affected by treatment×time (P = 0.001) where ITM was greater through 8-h for Zn and through 24-h for Mn and Se over all other treatments. Liver Se concentration was greater in ITM vs. other treatments through d-15 and Rel250 was greater than ITM and MMP on d-91 and greater than CON, MMD, MMP, and SFD on d-120 (treatment×time; P ≤ 0.001). Plasma Cu, and liver Cu, Mn, and Zn concentrations were unchanged by treatment (P ≥ 0.05). Liver Mn concentrations were least on d-2 and generally increased over time (P ≤ 0.001), while liver Zn concentrations were greatest on d-2 and least from d-29 onward (time; P ≤ 0.001). Liver Cu concentrations were greatest on d-15 and d-29 vs. other days (time; P ≤ 0.001). Overall, use of injectable trace mineral rapidly increased plasma Mn, Se and Zn, and liver Se concentrations. Oral treatments tested here exerted no effect on plasma or liver concentrations, while the multi-element bolus, Rel250, increased liver Se after 91-d.

Objective Regolith-Landform Mapping in a Regolith Dominated Terrain to Inform Mineral Exploration

An objective method for generating statistically sound objective regolith-landform maps using widely accessible digital topographic and geophysical data without requiring specific regional knowledge is demonstrated and has application as a first pass tool for mineral exploration in regolith dominated terrains. This method differs from traditional regolith-landform mapping methods in that it is not subject to interpretation and bias of the mapper. This study was undertaken in a location where mineral exploration has occurred for over 20 years and traditional regolith mapping had recently been completed using a standardized subjective methodology. An unsupervised classification was performed using a Digital Elevation Model, Topographic Position Index, and airborne gamma-ray radiometrics as data inputs resulting in 30 classes that were clustered to eight groups representing regolith types. The association between objective and traditional mapping classes was tested using the ‘Mapcurves’ algorithm to determine the ‘Goodness-of-Fit’, resulting in a mean score of 26.4% between methods. This Goodness-of-Fit indicates that this objective map may be used for initial mineral exploration in regolith dominated terrains.

Decomposition Behaviors of Tantalum-Niobium Ore in Sodium Hydroxide System

A new method for the decomposition of low-grade refractory tantalum-niobium ores using sodium hydroxide fusion was proposed. The effects of initial mineral particle size, alkali to ore mass ratio, decomposition temperature and decomposition time on the decomposition rate of the tantalum-niobium ore were investigated. The alkali to ore mass ratio, decomposition temperature and initial mineral particle size showed significant influence on the decomposition of tantalum-niobium ore. The results show that the decomposition rates of cassiterotantalite and pyrochlore in the ore can be above 98% and 99% respectively when the initial mineral particle size is less than 75µm, the mass ratio of alkali to ore is 1:1, the decomposition temperature is 650°C and the decomposition time is 30min.

Evidence for initial calcite-aragonite composition of Lower Algal Chert Member ooids and stromatolites, Paleoproterozoic Gunflint Formation, Ontario, Canada

The chert members of the Paleoproterozoic Gunflint Formation, Ontario, Canada, are commonly regarded as examples of primary silica chemical sediments. This interpretation is founded upon the ubiquitous nature of silica, high fidelity of preservation of microfossils found within, and lack of observed primary carbonate. Previous arguments for silica replacement of carbonate are based on indirect evidence and are largely dismissed. Thus, Gunflint microfossils are regarded as having lived in a silica-rich environment, which makes them unusual compared to most other pre-Phanerozoic microfossils that are known from silicified carbonates. We present evidence that carbonate was a primary mineral species of the Lower Algal Chert Member (where most of the microbiota are found). Most compelling are iron-stained, low-Mg calcite ooids containing (1) well-preserved growth laminae, (2) textures indicating a disrupted tangential fabric of growth laminae, and (3) quartz crosscutting the growth laminae. These indicate the initial mineral was a carbonate, possibly aragonite. Less-compelling evidence is found in stromatolite columns. Specularite crystals in low-Mg calcite display crosscutting relationships with calcite and quartz indicating that calcite was primary, specularite secondary, and quartz tertiary. The crosscutting relations show that silicification took place in at least two stages. One of the silicification events took place very early in diagenesis. Thus the Gunflint microbiota may not have existed in a radically different environment (silica precipitating) than those of most other known Proterozoic microbiota. High fidelity of preservation of microfossils does not always indicate that the mineral entombing them was the primary mineral precipitated from aqueous solution.