Fe, Ni, Co, and Cu in FeNi alloys of H Chondrites

This publication presents the results of chemical analyses of 173 FeNi alloy grains from four selected H ordinary chondrites: Thuathe, Chergach, Gao-Guenie and NWA 4555. Based on performed analyses and calculations, the following average chemical composition of the FeNi alloy was determined [in wt.%]: Fe - 90.75%; Ni - 8.80%; Co - 0.35%; Cu - 0.03%. The content of Cu and Co depends on the nickel content in the FeNi alloy. The low-nickel alloy represented by kamacite is enriched in cobalt (average content 0.38%) and depleted in copper (0.01%), while the high-nickel alloy, represented mainly by taenite, is characterized by a low content of cobalt (0.08%), and a significant enrichment in copper (0.16%). Based on these data, it is possible to approximate the resources of these metals in the parent bodies of these chondrites. For example, for the asteroid (143624) 2003 HMi6, which is classified as a Near Earth Object (NEO), such resources are [in Mg]: Fe - 2.4 · 109, Ni - 2.3 · 108, Co-9.2 · 106, Cu-7.9 · 105.

Far from boring: a new Grenvillian perspective on Mesoproterozoic tectonics

As determining when plate tectonics began on Earth is a highly debated subject, it is crucial to understand the “boring billion” (1.8 to 0.8 billion years ago), a period of tectonic quiescence inferred from proxies, such as the average chemical composition of the mineral zircon on Earth and the isotopic composition of seawater derived from marine rocks. Yet this period saw the construction of what may have been the biggest mountain belt that ever existed, the remnants of which are found in the Grenville Orogen of eastern North-America. This contribution first exposes a compilation of multidisciplinary geological datasets and new geochemical data from igneous suites emplaced during the Grenvillian Orogeny that are incompatible with the current tectonic paradigm. We then present a completely revised model for Grenvillian tectonics. In contrast with the actual Laurentian-centred paradigm, our model involves the construction of a newly revealed continent by amalgamation of volcanic arcs far away from Laurentia (the craton forming the core of actual North-America) and their collision 60 millions year later than the currently accepted timing. This new model resolves the longstanding contradiction between tectonic proxies and geological record and invalidates the view considering the Mesoproterozoic as a tectonically quiet Era.

Multi-Element Composition of Diatom Chaetoceros spp. from Natural Phytoplankton Assemblages of the Russian Arctic Seas

Data on the elemental composition of the diatom Chaetoceros spp. from natural phytoplankton communities of Arctic marine ecosystems are presented for the first time. Samples were collected during the 69th cruise (22 August–26 September 2017) of the R/V Akademik Mstislav Keldysh in the Kara, Laptev, and East Siberian Seas. The multi-element composition of the diatom microalgae was studied by ICP-AES and ICP-MS methods. The contents of major (Na, Mg, Al, Si, P, S, K and Ca), trace (Li, Be, B, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Mo, Ag, Cd, Sn, Sb, Cs, Ba, Hg, Tl, Pb, Bi, Th and U) and rare earth (Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) elements varied greatly, which was probably associated with the peculiarities of the functional state and mineral nutrition of phytoplankton in the autumn period. Biogenic silicon was the dominant component of the chemical composition of Chaetoceros spp., averaging 19.10 ± 0.58% of dry weight (DW). Other significant macronutrients were alkaline (Na and K) and alkaline earth (Ca and Mg) metals as well as biogenic (S and P) and essential (Al and Fe) elements. Their total contents varied from 1.26 to 2.72% DW, averaging 2.07 ± 0.43% DW. The Al:Si ratio for natural assemblages of Chaetoceros spp. of the shelf seas of the Arctic Ocean was 5.8 × 10−3. The total concentrations of trace and rare earth elements on average were 654.42 ± 120.07 and 4.14 ± 1.37 μg g−1 DW, respectively. We summarize the scarce data on the average chemical composition of marine and oceanic phytoplankton and discuss the limitations and approaches of such studies. We conclude on the lack of data and the need for further targeted studies on this issue.

The Skeleton of Giraffes

The giraffe skeleton consists of ~170 bones. The dry mass of the skeleton is 70 g.kg-1 body mass. The average chemical composition of their bones is 33% minerals (mainly calcium and phosphorus in a ratio of 2:1), 34% collagen, and 33% water. The skull contributes ~10%, the vertebrae ~25% and the limb bones ~65% to skeleton mass. The average density of all bones is 1.6 g cm-3, ranging from 0.8 g cm-3 (cervical vertebrae) to 2.0 g cm-3 (limb bones). Resistance to fracture by vertebrae depends on their cross-sectional area, and is greatest in cervical and the first few thoracic vertebrae. Resistance to fracture by limb bones depends on wall thickness (the difference between inner and outer diameter), which is uniquely thick. The growth of all limb bones except the humerus follows a geometric pattern (length and diameter increase at the same rate) which confers resistance to compression stress. The humerus follows an elastic pattern (diameter increases faster than length) a pattern that resists bending stress. Giraffes bones are exceptionally straight which further reduces bending stresses. The torque generated by the mass of the head and neck is resisted by the ligamentum nuchae which is exceptionally well-developed in giraffes, extends from the lumbar vertebrae to the occipital crest, can have a diameter of ~10 cm, and can support loads of ~1.8 tonnes before rupturing. As a giraffe grows muscle cross-sectional area (and contraction strength) declines and the duty factor reduces, both of which reduce the risk of fracture.

Research on the Synthesis of Proppants Applied for Oil Production by the Method of Hydraulic Facing

The essence of the hydraulic fracturing method for enhancing oil recovery is described. The definition of proppants is given and their average chemical composition is determined. In the process of an analytical review, the article presents proppants that are widely used in the oil industry. For each type of proppant, the main technical characteristics (bulk density and compressive strength) required when using the hydraulic fracturing method have been determined. In the course of the analysis, it was found that all proppant technologies are expensive and it is necessary to select high-quality cheap and affordable materials to reduce the cost of their production. Drilling cuttings from the Morozovskoye field were chosen as one of these materials. Physical and chemical studies of drill cuttings were carried out, on the basis of which a conclusion was made about the possibility of its use in the synthesis of high-quality aluminosilicate proppants.

Mineralogy and chemistry of a new halloysite deposit from the Rio de Janeiro pegmatite province, south-eastern Brazil

Halloysite is a 1:1 dioctahedral clay mineral that has been studied widely for applications in nanotechnology and as a mineral exploration guide for recognizing regolith-hosted heavy rare earth element (HREE) deposits. In Brazil, pegmatites from the state of Rio de Janeiro have been catalogued, but their potential to host halloysite deposits has never been studied. After a mineral exploration programme, one pegmatite with considerable halloysite contents and economic potential was discovered. This study reports the mineralogical and chemical characterization of the halloysite of this pegmatite and evaluates the possibility of clay-adsorbed HREE deposits, like that in the Zudong (China) regolith-hosted HREE deposit. Seven samples were collected in horizontal channels. Bulk samples and clay fractions (<2 μm) were analysed by quantitative mineral analysis (X-ray diffraction/Rietveld method), chemical analysis (major elements by X-ray fluorescence and Y, U, Th and rare earth elements by inductively coupled plasma mass spectrometry), scanning electron microscopy, Fourier-transform infrared spectroscopy, particle-size analysis, nitrogen physisorption and cation-exchange capacity. Mixed polygonal/cylindrical halloysite-7Å in concentrations between 6.3 and 35.4 wt.% in bulk samples and between 58.0 and 89.8 wt.% in the clay fractions were identified in the pegmatite. The clay fractions presented an average chemical composition of 45.46 wt.% SiO2, 36.10 wt.% Al2O3, 14.62 wt.% loss on ignition and 1.04 wt.% Fe2O3, as well as technological properties close to those observed in world-class halloysite deposits such as Dragon Mine (USA) and Matauri Bay (New Zealand). The clay minerals did not present significant HREE contents.

Supergénne minerály z U-Cu rudného výskytu Východná-Nižný Chmelienec v Nízkych Tatrách (hronikum, Slovensko)

An association of supergene U-Cu and Y/REE minerals was found in a relic of old ore dump at the abandoned U deposit occurrence Východná-Nižný Chmelienec, the northern slopes of the Nízke Tatry Mts., Slovakia. They have partially recent origin, since exploration of the locality took place between 1965 and 1966. The studied mineral assem- blage is represented by goethite, malachite, uranophane and (meta)zeunerite, in a lesser extent baryte and rare zálesíite. Uranophane appears separately (globular aggregates, thin coatings) and it also forms the main part of the yellow to yellow-green crystalline crusts on the rock cracks. The chemical composition of the uranophane was determined by electron microprobe analyses and it is close to its ideal chemical formula Ca(UO2)2(SiO3OH)2·5H2O. The average chemical composition of the studied uranophane can be expressed by an empirical formula (Ca1.0Mg0.02K0.01Fe0.01Ba0.01)Σ1.05 (UO2)2.08(SiO3OH)1.84·5H2O. The infrared vibrational spectra of the studied uranophane show 3 (UO2)2+ at 850-760 cm-1; the 3 (SiO4)4- antisymmetric stretching vibration at 1000-900 cm-1; the 1 (SiO4)4- symmetric stretching vibration at 1150-1199 cm-1; the  H2O bending vibration at 1800-1600 cm-1 and OH stretching vibrations at 3407; 3408 and 3409 cm-1. The weak bands 2648; 2646 and 2651 cm-1 may be assigned to organic impurities. The calculated U-O bond length 1.83 Å corresponds to short U-O bonds in uranophane. The accessory admixtures of uranophane coatings are (meta)zeunerite and zálesíite. (Meta)zeunerite occasionally forms thin coatings of light green to emerald green tabular crystals (up tu 0.5 mm) on the surface of the rocks. Chemical analyses of (meta)zeunerite correspond to the empirical formula (Cu0.66K0.03Fe0.01Ca0.01)Σ0.71(UO2)2.11[(AsO4)1.96(PO4)0.01]Σ1.97·12H2O. Zálesíite occurs as crystalline aggregates, nests, formed by tiny acicular crystals, up to 100 µm in length. This is the second finding (occurrence) of this mineral in Slovakia. An average zálesíite chemical composition is (Ca0.83REE0.18U0.05Al0.03Ti0.01)Σ1.10(Cu5.81Fe0.06Zn0.02)Σ5.90[(AsO4)2.75 (SiO4)0.21(PO4)0.02(SO4)0.03]Σ3.01(OH)5.10·3H2O. Malachite, which has been also found in the association, is only a minor mineral in the studied locality. The formation of uranyl silicates (uranophane) and minerals of the mixite group (zálesíite), present at the studied locality, points to neutralization of acidic supergene fluids in the mine dumps. Possibly, this environment later (precipitation of baryte) passed to neutral or slightly basic conditions (precipitation of carbonates - malachite). The identified uranyl phosphates/arsenates (zeunerite/metazeunerite), typical of an acidic environment, are therefore rare.

Hingganite-(Nd), Nd2□Be2Si2O8(OH)2, a new gadolinite-supergroup mineral from Zagi Mountain, Pakistan

ABSTRACT Hingganite-(Nd), ideally Nd2□Be2Si2O8(OH)2, is a new gadolinite group, gadolinite supergroup mineral discovered at Zagi Mountain, near Kafoor Dheri, about 4 km S of Warsak and 30 km NW of Peshawar, Khyber Pakhtunkhwa Province, Pakistan. The new mineral forms zones measuring up to 1 × 1 mm2 in loose prismatic crystals up to 0.7 cm long, where it is intergrown with hingganite-(Y). Other associated minerals include aegirine, microcline, fergusonite-(Y), and zircon. Hingganite-(Nd) is dark greenish-brown, transparent, has vitreous luster and a white streak. It is brittle and has a conchoidal fracture. No cleavage or parting are observed. Mohs hardness is 5½–6. Dcalc. = 4.690 g/cm3. Hingganite-(Nd) is non-pleochroic, optically biaxial (+), α = 1.746(5), β = 1.766(5), γ = 1.792(6) (589 nm). 2Vmeas. = 80(7)°; 2Vcalc. = 84°. Dispersion of optical axes was not observed. The average chemical composition of hingganite-(Nd) is as follows (wt.%; electron microprobe, BeO, B2O3, and Lu2O3 content measured by LA-ICP-MS; H2O calculated by stoichiometry): BeO 9.64, CaO 0.45, MnO 0.10, FeO 3.03, B2O3 0.42, Y2O3 8.75, La2O3 1.63, Ce2O3 12.89, Pr2O3 3.09, Nd2O3 16.90, Sm2O3 5.97, Eu2O3 1.08, Gd2O3 5.15, Tb2O3 0.50, Dy2O3 2.50, Ho2O3 0.33, Er2O3 0.84, Tm2O3 0.10, Yb2O3 0.44, Lu2O3 0.04, ThO2 0.13, SiO2 23.55, H2O 2.72, total 100.25. The empirical formula calculated on the basis of 2 Si apfu is (Nd0.513Ce0.401Y0.395Sm0.175Gd0.145Pr0.096Dy0.068La0.051Ca0.041Eu0.031Er0.022Tb0.014Yb0.011Ho0.009Tm0.003Th0.003Lu0.001)Σ1.979(□0.778Fe2+0.215Mn0.007)Σ1.000(Be1.967B0.062)Σ2.029Si2O8.46(OH)1.54. Hingganite-(Nd) is monoclinic, space group P21/c with a = 4.77193(15), b = 7.6422(2), c = 9.9299(2) Å, β = 89.851(2)°, V = 362.123(14) Å3, and Z = 2. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 6.105 (95) (011), 4.959 (56) (002), 4.773 (100) (100), 3.462 (58) (102), 3.122 , 3.028 (61) (013), 2.864 (87) (121), 2.573 (89) (113). The crystal structure of hingganite-(Nd) was refined from single-crystal X-ray diffraction data to R = 0.034 for 2007 unique reflections with I &gt; 2σ(I). The new mineral is named as an analogue of hingganite-(Y), hingganite-(Yb), and hingganite-(Ce), but with Nd dominant among the rare earth elements.

Physical-chemical and sensory evaluation of cookie made with potato (Solanum Tuberosum L.) and beet (Beta Vulgaris L.) Mixed flour

This study aimed to develop a cookie from the mixed flour derived from dehydrated pulp of beet and potatoes, by drying in a tray dryer and assessing their physical-chemical and sensory characteristics. Three formulations were prepared: Standard (0%), Type I (10%) and Type II (20%). The percentage correspond to the mixed flour added to the basic formulation. The data of the flour drying process showed a moisture loss of the potatoes and beet around 83.5 and 86.2%, respectively. The Type I and II cookies had an average chemical composition respective 0.3 to 0.7% moisture, 70% carbohydrates for both, 5 and 7% protein, 22 and 20% fat and 2% minerals for both, with an average calorific value of 505 and 491 kcal x 100 g-1. All formulations showed satisfactory acceptance through sensory analysis, and there was no statistical difference between the types of cookie for all attributes. The model Midilli describes the drying kinetics with a good parameter of fit. So, this product is very promising, taking into account the range of additional nutrients from the raw materials (mainly minerals), calorific value similar to those found on Brazilian market and consumer acceptance, besides the possibility of use as a coloring agent.

Geochemistry of the Athabasca Basin, Saskatchewan, Canada, and the Unconformity-related Uranium Deposits Hosted By It

A large data set comprising near-total digestion analyses of whole rock samples from the Athabasca Basin, Saskatchewan, Canada (based principally on the Geological Survey of Canada open file 7495), containing more than 20,000 analyses, was used to define the average chemical composition of Athabasca Group sandstones and of unconformity-related uranium deposits hosted by the basin. The chemical composition of unaltered and un-mineralized Athabasca Group sandstones is dominated by Al (median Al2O3 of 1.14 wt.%), Fe (median Fe2O3 of 0.24 wt.%), and K (median K2O of 0.11 wt.%; Si was not measured), corresponding mostly to the presence of kaolin, illite, and hematite, in addition to the most-abundant quartz. The median concentration of U in the barren sandstones is 1 ppm, with 5 ppm Th, 3 ppm Pb, and 56 ppm ΣREE. Other trace elements present in significant amounts are Zr (median of 100 ppm), Sr (median of 69 ppm), and B (median of 43 ppm), corresponding to the presence of zircon, illite, and dravite. The elements most enriched in a typical Athabasca Basin unconformity-related uranium deposit relative to the barren sandstone are U (median enrichment of ×710), Bi (×175), V (×77), and Mg (×45), followed by five elements with enrichment factors between 20 and 30 (Co, Mo, K, As, and Ni). These correspond to the presence in the ore bodies of alteration minerals (dravite, kaolinite, illite, chlorite, aluminum-phosphate-sulfate minerals, and a suite of sulfide minerals) and are similar to what has been observed before. These elements are similar to the typical pathfinder elements described above known deposits, but their usefulness has to be assessed based on their relative mobility in the predominantly oxidizing Athabasca Basin sandstones.