Wide Variation In Composition Research Articles

The Five-Factor Model of Indigenous Studies: A Quantitative Content Analysis of Postsecondary Indigenous Studies Websites in Canada, the United States, Australia, and New Zealand

Indigenous Studies (IS) is a multidisciplinary academic discipline chartered to offer more than just an education about Indigenous peoples. Indigenous Studies is a fought-for space on campus to properly represent the perspectives, processes, and communities of Indigenous peoples, for the benefit of Indigenous communities, organizations, and interests. Unfortunately, the extent to which IS fulfills its mission is ambiguous due to the wide variation in IS program composition, the broad scope of the discipline’s topical foci, and the lack of parameters or core ingredients that distinguish it from other disciplines. In this article, we describe the process and results of a content analysis of IS websites in the United States, Canada, Australia, and New Zealand. The goal of this study was to identify the major features of IS internationally and to show how IS programs vary in their embodiment of those major features. After an extensive coding process, we ran an exploratory factor analysis on the quantitative codings to derive a five-factor model of IS. Accordingly, IS included (1) Indigenous methodologies, (2) Indigenous community member involvement, (3) Indigenous Ways of Knowing and Doing, (4) Indigenous languages, and (5) Indigenous student community. How much these factors were emphasized depended on the country, institution type, and level of degree offered, controlling for website complexity and aesthetics. Our findings show that there is common ground across IS programs internationally, according to their websites, but that some countries (e.g., Canada), institution types (e.g., tribal colleges), and degree programs (e.g., undergraduate) reflect these factors more than others.

Petrogenesis of post-orogenic Pan-African rare-element granitic pegmatites in the western Arabian-Nubian Shield, Aswan area, southern Egypt

• Aswan pegmatites evolved via fractional crystallization of the parental granitic magma . • The rare-element pegmatites were formed in a post-orogenic setting. • Post-magmatic hydrothermal fluids play an important role in their formation. Pegmatites with rare-element mineralization from the Aswan area in southern Egypt intruded the post-orogenic Pan-African granitic rocks and the associated gneisses. The granitic pegmatites show a regular pattern of concentric zoning and display a weak affinity to the Nb-Y-F (NYF) pegmatite family. These pegmatites consist mainly of K-feldspar, albite, quartz, and subordinate muscovite, accessory minerals include Nb-Ta oxide minerals, monazite-(Ce), xenotime-(Y), zircon, rutile, and magnetite. Field observations combined with the petrography, mineralogy and geochemistry of pegmatites and associated rocks in the Aswan area indicate that the pegmatites evolved via fractional crystallization of the parental granitic magma with an effective role for the post-magmatic alterations. The wide compositional variations of Nb-Ta minerals in term of their major and trace elements reflect the pegmatite formation stages. Primary magmatic generation of columbite-(Fe) occurs as homogeneous grains or showing oscillatory zoning with high Nb/Ta and Fe/Mn ratios. Late ixiolite shows patchy and irregular zoning with high Sc and W replacing the earlier regular texture, indicating metasomatic replacement. Electron microprobe U–Th–Pb dating of monazite from the studied pegmatites yielded post-orogenic Pan-African age of 578 ± 5 Ma, comparable with age of the fine-grained granite in this area, but it is younger than the previously estimated U–Pb zircon age of surrounding the Monumental granites and gneisses (∼600 to 620 Ma). The similarity in age and geochemical characteristics of the pegmatites and the fine-grained granite proved their genetic relationship.

Role of fractional crystallization and partial melting in the generation of intermediate and acidic magmas of the Andaman Island Ophiolite suite of India

The Mesozoic‐age Andaman Island Ophiolite located in the southeastern fringe of the Indian plate margin is one of the well‐preserved supra‐subduction‐zone oceanic lithospheric slices. It is tectonically associated with the Indonesian arc system and is an extension of the Phanerozoic Indonesian‐Myanmar orogenic belt. Thus, it offers a unique opportunity to study oceanic crust formation and specify magma evolution processes in the Tethyan subduction system. The volcanics of the Andaman Islands ophiolite display a wide compositional variation. Rock types vary from basic (basalts) to intermediate (basaltic‐trachyandesites, basaltic andesites) to acidic differentiates like dacites and rhyolites. This contribution presents the petrochemistry of the intermediate rock types—basaltic‐trachyandesites, trachyandesites and acidic—dacites and rhyodacites of Andaman Island Ophiolite (India). This study examines the role of fractional crystallization and partial melting in the generation of intermediate and acidic magmas of the Andaman Ophiolite suite. Plagioclases and pyroxenes are the major mineral constituents of these rocks on petrographic observation. Plagioclases of the intermediate rocks are of albite composition Ab98‐99. The acidic rocks show compositional variation from albite to oligoclase (Ab83–99). Analysed pyroxenes of intermediate and acidic rocks are augite (Wo46–49En34–41Fs13–17). The studied calc‐alkaline rocks show variable abundance of Large‐Ion Lithophile Elements and display strong positive Pb and negative Ti anomalies. The chondrite‐normalized Rare Earth Elements display an enriched pattern with varying degrees of enrichment. Clinopyroxene thermobarometry reveals that the intermediate magma and acidic magma becomes saturated with clinopyroxene at 1,062–1,133°C and 1,016–1,079°C, respectively, at 2 kbar and H2O = 2 wt%. Petrochemical findings and model calculations using PELE are consistent with a derivation of intermediate rocks from the basaltic melt by fractional crystallization. In contrast, acidic rocks are the product of partial melting of hydrothermally altered oceanic crust. The association of basaltic and intermediate rocks suggests a relatively stable magma chamber to generate differentiated intermediate magmas by fractional crystallization.

An Overview on Solid Waste Generation and Management: Current Status in Chile

The widespread generation of, ever increasing volumes of and the sustainable management of solid wastes are global issues of great concern. Due to wide variations in composition and associated complexities, significant efforts are required for their collection, processing and environmentally safe disposal in a cost effective manner. An overview of solid wastes is presented in this article with a specific focus on municipal solid wastes and industrial waste from the iron/steelmaking and aluminium industries. Key waste issues such as its sources, compositions, volumes, the factors affecting waste generation and waste processing are first discussed, followed by a further discussion regarding recycling, resource recovery, disposal and the associated environmental impacts. In a special case study, waste generation and management in Chile is presented in greater detail. Detailed information is provided on government initiatives and legislation for integrated solid waste management and its movement towards a circular economy. Measures include regulations on waste management framework which concerns the transboundary movements of hazardous wastes, persistent organic pollutants, the closure of mining activities and installations and restrictions on plastics disposal. With Chile being world’s largest producer of copper, significant efforts for mining waste management, its infrastructure and procedures are being put in place to reduce the environmental impact of the mining sector and its associated waste generation.

PD03-05 THE ROLE OF UROLOGY PRACTICE ORGANIZATION AND RACIAL COMPOSITION ON PROSTATE CANCER TREATMENT DISPARITIES

You have accessJournal of UrologyHealth Services Research: Practice Patterns, Quality of Life and Shared Decision Making I (PD03)1 Sep 2021PD03-05 THE ROLE OF UROLOGY PRACTICE ORGANIZATION AND RACIAL COMPOSITION ON PROSTATE CANCER TREATMENT DISPARITIES Nnenaya A. Mmonu, Yongmei Qin, Samuel Kaufman, Mary Oerline, Christina Chapman, Brent K. Hollenbeck, and Ted A. Skolarus Nnenaya A. MmonuNnenaya A. Mmonu More articles by this author , Yongmei QinYongmei Qin More articles by this author , Samuel KaufmanSamuel Kaufman More articles by this author , Mary OerlineMary Oerline More articles by this author , Christina ChapmanChristina Chapman More articles by this author , Brent K. HollenbeckBrent K. Hollenbeck More articles by this author , and Ted A. SkolarusTed A. Skolarus More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000001967.05AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Though Black men have a higher risk of prostate cancer diagnosis and mortality, they are less likely to receive definitive treatment. Understanding the extent to which urology practice organization and racial composition might be associated with treatment patterns may lead to actionable insights to address disparities. METHODS: We identified Medicare beneficiaries diagnosed with prostate cancer between January 2010 and December 2015, and followed them through 2016. We identified a primary urologist for each patient; urologists were assigned to practices based on their Tax Identification Number (TIN). Each patient was assigned a unique TIN based on their primary urologist. We grouped TINs into quartiles based on the proportion of Black patients in a urology practice, with increasing quartile number (1-4) representing increasing proportion of Black patients (0-100%). We used multivariable regression to identify treatment associations. RESULTS: We identified 54,443 patients with incident prostate cancer assigned to 4,194 practices. The majority of patients were White (87%) with 9% Black. We found wide variation in racial practice composition (Figure). Some practices were comprised of no Black patients, while others were comprised of nearly all Black patients. The highest quartile comprised 955 practices with an average of 20% Black patients. This quartile had the greatest degree of low socioeconomic status (43.1%), higher comorbidity, and the youngest age of incident prostate cancer (all p<0.01). Black patients had lower odds of definitive therapy (adjusted odds ratio (aOR)=0.87, 95% confidence interval (CI): 0.81, 0.93). Patients with medium or high socioeconomic status also had higher odds of treatment (medium vs. low, aOR 1.09, 95% CI 1.04, 1.15; high vs. low, aOR 1.06, 95% CI 1.00, 1.12). Black patients underwent less surgery, more radiation, and cryotherapy than White patients. CONCLUSIONS: Though Black patients have higher diagnosis and mortality from prostate cancer, we found lower treatment rates despite Medicare insurance coverage. The associations of racial practice composition with treatment patterns and patient characteristics are reflective of the adverse effects of structural racism on prostate cancer disparities, and highlight the need for multilevel interventions to mitigate implications. Source of Funding: NIH © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e45-e46 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Nnenaya A. Mmonu More articles by this author Yongmei Qin More articles by this author Samuel Kaufman More articles by this author Mary Oerline More articles by this author Christina Chapman More articles by this author Brent K. Hollenbeck More articles by this author Ted A. Skolarus More articles by this author Expand All Advertisement Loading ...

Geochemistry of Sphalerite from the Permian Volcanic-Hosted Massive Sulphide (VHMS) Deposits in the Tasik Chini Area, Peninsular Malaysia: Constraints for Ore Genesis

The Bukit Botol and Bukit Ketaya deposits are two examples of volcanic-hosted massive sulphide (VHMS) deposits that occur in the Tasik Chini area, Central Belt of Peninsular Malaysia. The mineralisation is divided into subzones distinguished by spatial, mineralogical, and textural characteristics. The primary sulphide minerals include pyrite, chalcopyrite, sphalerite, and galena, with lesser amounts of Sn- and Ag-bearing minerals, with Au. However, pyrrhotite is absent from both deposits. This study presents the results of sphalerite chemistry analysed by using an electron microprobe. Two types of sphalerite are recognised: sphalerite from the Bukit Botol deposit reveals a range of &lt;DL to 24.0 mole% FeS, whereas sphalerite from the Bukit Ketaya deposit shows a range of &lt;DL to 3 mole% FeS. Significant variations are shown in Zn, Cu, Cd, and Ag levels. Although the sphalerite has a wide variation in composition, a discernible decreasing Fe trend is exhibited from the stringer zone towards massive sulphide. This compositional variation in sphalerites may in part reflect variable temperature and activity of sulphur in the hydrothermal fluids during ore formation. Alternatively, the bimodal composition variations suggest that mineral chemistry relates to contrasting depositional processes. The Zn/Cd ratios for sphalerite from both these deposits are similar to those exhibited by volcano−sedimentary deposits with a volcanic origin. Therefore, the consistently low Cd concentrations and moderate to high Zn/Cd ratios suggest mixing of seawater and minor magmatic fluids controlling the chemistry of sphalerite at both deposits during their formation.

Post-Ore Processes of Uranium Migration in the Sandstone-Hosted Type Deposits: 234U/238U, 238U/235U and U\u2013Pb Systematics of Ores of the Namaru Deposit, Vitim District, Northern Transbaikalia

To assess the nature of the post-ore behaviour of uranium in the Namaru deposit (Khiagda ore field), U–Pb isotope systems and the isotopic composition of uranium (234U/238U and 238U/235U) were studied. The studied samples represent different ore zones of the deposit and were collected along cross-sections both vertically and horizontally. Wide variations in the isotopic composition of uranium and U–Pb isotopic age have been established. Deviations of the 234U/238U ratio from equilibrium values, which for some samples exceed 50%, along with significant variations in the isotopic age, indicate that permafrost layer, which covered the catchment areas of paleovalleys with meteoric oxygen-containing waters ca. 2.5 Ma ago, did not lead to preserving uranium ores at the deposit. Uranium migration took place during the Quaternary period. The effective combining the U–Pb dating and 234U/238U data in assessing the post-ore redistribution of uranium made it possible to recognize: removal of uranium from some zones of the ore body and its accompanying redeposition in others. Wide variations in the 238U/235U (137.484–137.851) ratios throughout the entire studied cross-sections can be explained by the different locations of samples relatively to the ore deposition front and change in redox conditions as this front advanced. Depletion of the light isotope 235U in the lower zone of the ore body may be associated with the influence of ascending carbonic waters established in the regional basement. The effect of such waters on uranium-bearing rocks causes predominant leaching of light 235U.

Compositional Evolution of the Variscan Intra-Orogenic Extensional Magmatism in the Valencia del Ventoso Plutonic Complex, Ossa-Morena Zone (SW Iberia): A View from Amphibole Compositional Relationships

The Ossa-Morena Zone (OMZ), SW Iberia, has numerous Lower Carboniferous compositionally zoned plutons that formed in a Variscan intra-orogenic extensional setting. This magmatism shows a wide compositional variation comprising alkaline, transitional, and calc-alkaline suites. The calc-alkaline suite was produced by hybridization of alkaline magmas with felsic melts generated by crustal anatexis related to the intrusion of mafic magmas in the middle crust. In this work, we present a textural and mineralogical study of the Variscan Valencia del Ventoso main pluton from the OMZ to track the compositional evolution of magmas during hybridization using constraints from amphibole compositions and to determine the P-T conditions of emplacement using amphibole-based thermobarometry. This pluton exhibits reverse zoning with an inner facies containing alkaline dolerites, gabbros, and quartz diorites, an intermediate facies with transitional diorites, and an outer facies with calc-alkaline quartz diorites to monzogranites. Magmas from the intermediate and border facies crystallized under oxidizing conditions at relatively low temperatures (range: 640–760 °C) and ca. 280–300 MPa, implying near H2O-saturated conditions. These rock facies show mineralogical evidence of hybridization between alkaline to mildly alkalic and calc-alkaline magmas. The former is inferred from the occurrence of antecrysts of labradorite-andesine, high-Ti pargasite-hastingsite, and biotite with deficiency in tetrahedral-site occupancy, a distinctive feature of biotite from the inner facies alkaline dolerites. This contrasts with later crystallization from the calc-alkaline magma of andesine-oligoclase, low-Ti magnesiohornblende-edenite, and biotite with full tetrahedral-site occupancy. Constraints from amphibole-melt compositional relationships in antecrystic high-Ti amphibole suggest that the alkaline magmatic component could have a high- to ultra-K affinity.

Fuel Effects on Engine-out Emissions Part 1 - Comparing Certification and Market Gasoline Fuels

&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;Studies have shown that fuel quality plays an important role in engine-out emissions. The wide variation in composition and properties of gasoline fuels available in the market can lead to discrepancies between the expected emission levels as per set regulations and actual on-road measurements.&lt;/div&gt;&lt;div class="htmlview paragraph"&gt;This study compares engine-out gaseous and particulate emission results between 5 US market fuels, 5 certification fuels and one street-legal race fuel. The market fuels were acquired from different terminals in Michigan. Tests were performed on a 4-cylinder 2.3 L turbocharged direct injection spark-ignited engine. The tests covered a wide range of steady-state operating conditions including load, injection timing and engine speed sweeps. Transient load steps were also performed under warm and cold engine conditions.&lt;/div&gt;&lt;div class="htmlview paragraph"&gt;Weighting factors were assigned to the emissions results from the steady-state operating points in the study; these factors were based upon the frequency of visitation of respective point during an aggressive real drive emission cycle. This was then used to assign a ranking to the fuels.&lt;/div&gt;&lt;div class="htmlview paragraph"&gt;The results from the study indicated that even within the US market-compliant gasoline fuels significant differences existed between the engine out particulate number (PN) and unburned hydrocarbon (HC) emissions, particularly at high load and under cold transient conditions—with more than 200x difference in the PN emissions and 1.5x difference in HC emissions. Furthermore, statistically significant differences existed between the engine out PN emissions of certification and market gasoline fuels, due to differences in their composition and properties. Lastly, significance of higher fuel injection pressures and optimum injection timing was demonstrated to reduce the sensitivity of the engine-out emissions to the fuel type.&lt;/div&gt;&lt;/div&gt;

Chemical Composition and Genesis Implication of Garnet from the Laoshankou Fe-Cu-Au Deposit, the Northern Margin of East Junggar, NW China

In order to reveal the formation mechanism of different garnets and its implications for the fluid evolution in the Laoshankou Fe-Cu-Au deposit in the northern margin of East Junggar (NW China), three types of garnet have been investigated in detail in this study. (1) Type 1 grossular, formed at Ca-silicate stage (stage I, the pre-mineralization stage), was replaced by Type 2 garnet and magnetite, and displays a compositional range of Grs44–53Adr44–53, which has relatively lower total REE (rare earth elements) contents (8.14–32.8 ppm) and markedly depleted LREE (light rare earth elements) with distinctive positive Eu anomaly (1.36–9.61). (2) Type 2 Al-rich andradite, formed at the early sub-stage of amphibole-epidote-magnetite stage (stage II, the main magnetite mineralization stage), can be divided into two sub-types, i.e., Type 2a and Type 2b. Type 2a garnets exhibit polysynthetic twinning and relatively narrow compositional variations of Adr63–66Grs31–34 with HREE-(heavy rare-earth elements) enrichment and positive Eu anomalies (3.22–3.69). Type 2b garnets own wide compositional variations of Adr55–77Grs21–43 with relatively higher REE contents (49.1–124 ppm), markedly depleted LREE and a distinctive positive Eu anomaly (2.11–4.61). (3) Type 3 andradite (Adr&gt;91) associated with sulfide stage (stage III, the main copper-gold mineralization stage) is different from other types of garnets in Laoshankou, which are characterized by lowest total REE contents (1.66–91.1 ppm), flat HREE patterns, LREE-enrichment and the strongest positive Eu anomalies (3.31–45.48). Incorporation of REE into garnet is largely controlled by external factors, such as fluid chemistry, pH, ƒO2 and water-rock ratios as well as its crystal chemistry. Type 1 and 2 garnets mainly follow the creation of X2+ (e.g., Ca2+) site vacancy, e.g., [X2+]−3VIII[]+1VIII[REE3+]+2VIII. The REE3+ substitution mechanism for Type 3 garnet is the Na+-REE3+ coupled substitutions, e.g., [X2+]−2VIII[X+]+1VIII[REE3+]+1VIII, without the evaluation of the creation of site vacancy. The compositional variations from Type 1 to Type 3 garnet indicate significant differences of fluid compositions and physicochemical conditions, and can be used to trace the fluid–rock interaction and hydrothermal evolution of garnet. Type 1 grossular was formed by magmatic fluid under low water–rock ratios and ƒO2, and neutral pH environment by diffusion metasomatism in a nearly closed system with the preferential incorporation into the grossular of HREE. As the long fluid pore residence and continuing infiltration metasomatism under nearly closed-system conditions, fluids with high water/rock ratios were characterized by increased ƒO2, more active incorporation of Fe3+ and REE, and formed Type 2 Al-rich andradite. In contrast, Type 3 garnet formed by oxidizing magmatic fluid under a mildly acidic environment with highest ƒO2 and water–rock ratios, and was influenced by externally derived high salinity and Ca-rich fluids in an open system. Thus, the geochemical features of different types and generations of garnets in the Laoshankou deposit can provide important information of fluid evolution, revealing a transition from neutral magmatic fluid to oxidizing magmatic fluid with addition of external non-magmatic Ca-rich fluid from the Ca-silicate stage to the sulfide stage. The above proved the fluid evolution process further indicates that the Laoshankou deposit prefers to be an IOCG-like (iron oxide-copper-gold) deposit rather than a typical skarn deposit.

Towards integrated cover crop management: N, P and S release from aboveground and belowground residues

Ecological intensification is crucial for arable organic farmers, in order to partly close the yield gap to conventional yields. One strategy for this is improved management of cover crops, to increase availability of both nitrogen (N), phosphorus (P) and sulfur (S) for the subsequent main crop. However, the potential of cover crops to take up and release nutrients has primarily been determined for aboveground biomass and mostly for N. There have been fewer studies on belowground biomass, and these have focused on recoverable roots. Thus, unrecoverable residues from rhizodeposits and nodules, have been overlooked. The aim of this incubation study was therefore to assess the release of N, P and S from aboveground residues and from intact soil with belowground residues of different cover crop species at low temperature. Shoots and intact soil with roots from seven different cover crops were incubated for 80 days at a temperature of 5 °C.A comparison of the cover crop species revealed a wide variation in nutrient uptake, chemical composition and release of N, P and S, that also varied between shoot and intact soil with roots. Release of N from shoots showed a marked non-stoichiometric behavior, in contrast to the release of P and S, that correlated well with C:P and C:S ratios. N release (from Vicia villosa) and especially P mobilization (from legumes) in intact soil was much greater than the amounts determined in recoverable roots. This shows that unrecoverable pools such as rhizodeposits and fine roots contributed to nutrient release. Garden sorrel (Rumex acetosa) is a promising cover crop regarding uptake and mobilization of P, but also as a multifunctional cover crop for supplying N, K, S and Mg. Hairy vetch (Vicia villosa) is a promising cover crop for N, oilseed radish (Raphanus sativus) for S, P and K, and white lupin (Lupinus albus) for N, P and Mn supply.Based on our results, we propose the use of mixtures of cover crops with different N, P and S uptake and release having the potential to supply a more complete suite of nutrients to the subsequent crop.

NUTRITIONAL PERFORMANCE OF GROWING SHEEP FED SILAGE OF SALT TOLERANT PLANTS UNDER SOUTH SINAI CONDITIONS

This experiment was conducted at Ras Sudr Research Station belonging to Desert Research Center to elucidate the effect of feeding salt tolerant plants (Atriplex nummularia, Fodder beet, Pearl millet) silage (STPS) on productive performance ofmale Barki sheep under arid and salinity conditions of Southern Sinai, Egypt. Sixteen male Barki sheep (31.42 ±1.79 kg and 4 months age) were randomly divided into two equal groups (8 each). The first group (control) was fed 40% berseem hay (BH) from total ration and served as control. The second group (STPS) was fed ad liptum salt tolerant plants silage (Atriplex nummularia 50%, Fodder beet 35% and Pearl millet 10%) and the final mixture was sprayed with 5% molasses. All experimental lambs were fed concentrate feed mixture (CFM) as 60% percentage for total rations according to nutrient requirements. Results revealed that wide variations in chemical composition of the experimental roughages. It can be seen that STPS have lower contents of Dry matter (DM), Organic matter (OM), Crude protein (CP), Natural detergent fiber (NDF), Acid detergent fiber (ADF), than BH. However, STPS was higher than BH in ash content. Voluntary feed intake showed not significant differences between the two experimental groups of total and CFM intake. However, STPS group had lower (P< 0.05) roughage intake than control group. Animals fed STPS had higher (P<0.05) crude protein digestibility than the control group. Moreover, there were not significant differences between the two experimental groups of DM, CF, NDF and ADF digestibility. Feeding STPS lowered (P<0.05) free drinking, fecal, urinary and total water execration than control group. Ruminal parameters declared that, there were no significant (P< 0.05) differences in pH values, ammonia nitrogen concentration and total volatile fatty acids concentrations. Commonly, all ruminal parameters in the present study were within normal range of sheep. Blood biochemistry parameters showed significant (P<0.05) increase only for total proteins in control group compared to STPS group. Vastly, all values of blood biochemistry were within the normal ranges. Results of blood picture parameters except for WBC's (significantly decreased for STPS group) were not affected (P< 0.05) by the experimental rations fed to lambs. Weights of fattened lambs are didn’t appear any significant (P<0.05) differences between groups. On the other hand, the cheapest price of roughage for STPS group reflected positively on economical evaluation than that resulted by BH. It could be concluded that feeding salt tolerant plants silage without serious nutritional hazards, would be an avenue to overcome the problem of feedstuff shortage prevailed under arid and salinity conditions of Sinai, Egypt.

Thermodynamic modeling and elemental migration for the early stage of rodingitization: An example from the Xialu massif of the Xigaze ophiolite, southern Tibet

The analysis of early stage rodingite from the ultramafic rocks of the Xialu Massif in the Xigaze Ophiolite, Tibet, in China shows that the rodingitization involved continuous changes in fluid composition during different stages of subduction. The early stage prehnite-bearing rodingite was produced at low pressures and temperatures along extensional fractures. Samples of rodingite were collected along a profile from the center to the margin of a rodingitized intrusive igneous rock (~10 m × 30 m), and they record wide variations in bulk composition, mineralogy, and texture. The mineral assemblages, from center to margin, vary from (1) relics of primary clinopyroxene (Cpxr) and primary amphibole (Ampr) + newly formed late amphibole (Act) + primary plagioclase (Plr) + clinozoisite + prehnite + albite + chlorite + titanite + ilmenite (R1 rodingite), through (2) relics of primary clinopyroxene (Cpxr) + newly formed late clinopyroxene (Cpxn) + primary and late amphiboles (Ampr + Act) + clinozoisite + prehnite + albite + chlorite + titanite (R2 rodingite), to (3) newly formed late clinopyroxene (Cpxn) and amphibole (Act) + clinozoisite + prehnite + albite + chlorite + titanite (R3 rodingite). As a result of the metasomatic process of rodingitization, the content of CaO in the whole rock chemical composition from R1 to R3 increases, SiO2 decreases, and Na2O + K2O is almost completely removed. Mass-balance diagrams show enrichments in large ion lithophile elements such as Rb, Cs, Ba, and Pb as well as Ni during rodingitization. The central part of the rodingitized intrusion (R1 rodingite) was only slightly affected by metasomatism. On the other hand, the contents of the rare earth elements (REEs), high field strength elements (HFSEs; e.g. Zr, Nb, Ta, Hf, and Y), and some highly compatible elements such as Cr and Sc decreased slightly during rodingitization. Thermodynamic modeling based on equilibrium mineral assemblages indicates that the rodingite of the Xialu Massif formed in an H2O-saturated, CO2-rich environment. The estimated conditions of metamorphism were ~281–323 °C and 0.4–3.9 kbar, representing the subgreenschist facies. In this environment, REEs and HFSEs were soluble in the fluids and partly removed. Moreover, these prehnite rodingites formed in a progressively reducing and less alkaline environment, as indicated by decreases in f(O2) and bulk-rock Fe3+/Fe2+ ratios, and the records of fluid ΔpH from the center to the margin of the studied rodingitized intrusion.

Glauconite within Albian-Cenomanian Aitamir Formation, Kopet-Dagh Basin, northeastern Iran: origin and implications of cretaceous seawater

An integrated petrographical, geochemical, and mineralogical investigation reveals the wide variation in the mineral chemical composition of glauconites within the Albian-Cenomanian Aitamir Formation. Bounded between a black shale (Sanganeh Formation) below and chalky limestone (Abderaz Formation) above the Aitamir Formation represents an inner shelf deposit. Glauconite may occur either as pellets or as altered zones within feldspar and mica. Poor sorting and deeply penetrative crack indicate the authigenic nature of glauconite pellets. The contents of Fe2O3, MgO, Al2O3, and SiO2 of glauconites vary widely while the K2O exhibits a limited spread indicating the evolved nature of the glauconite. The glauconite matures at a fixed and high value of K2O with variable Fe2O3 (total) supporting the replacement origin. The X-ray diffraction study reveals a negligible interstratification within glauconites. The micro-textural study attests to the highly evolved nature of the glauconite. The shallow marine glauconite within the Albian-Cenomanian Aitamir Formation formed under sub-oxic, shallow depositional setting during the middle Cretaceous global warming phase within the Tethyan domain.

Trace elements in sulfides from the Maozu Pb-Zn deposit, Yunnan Province, China: Implications for trace-element incorporation mechanisms and ore genesis

Abstract The Sichuan-Yunnan-Guizhou Pb-Zn metallogenic province (SYGMP) is an important region for Pb-Zn resources in China. However, considerable controversy remains as to whether the Pb-Zn deposits are Mississippi Valley Type (MVT). The Maozu deposit, a typical example of the carbonate-hosted Pb-Zn deposits in the SYGMP, occurs in the late Ediacaran Dengying Formation and its ore bodies are divided into three types: lower layer (LL), vein layer (VL), and upper layer (UL) ore bodies based on their spatial relationship. In this study, laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) was used to systematically analyze the trace-element compositions of sphalerite and galena in these three ore bodies. The results show that sphalerite is characterized by Cd and Ge enrichment; Fe, Mn, and Co depletion; and local In and Sn enrichment. Most of these elements likely appear as solid solutions in sphalerite and show a wide compositional variation, which is probably related to the medium- and low-temperature mixing of the ore-forming fluids. The local enrichment of In and Sn is likely attributed to the long-distance migration of ore-forming fluids through In-Sn-bearing volcaniclastic rocks. In vs. Sn and (Cu + Sb) vs. (Ag + Ge) show strong correlations and similar element distribution in the mapped images, indicating that these elements may be incorporated into sphalerite via a coupled substitution for Zn as 2In3+ + Sn4+ + 2☐ ↔ 5Zn2+ (☐ = vacancies) and 4(Cu+ + Sb3+) + (Ge4+ + 2Ag+) + 2☐ ↔ 13Zn2+. Galena is enriched in Ag and Sb with minor Cd and Se and depleted in Bi, and most of the elements may occur as solid solutions. Ag vs. Sb in galena displays a strong positive correlation, implying the coupled substitution of Ag+ + Sb3+ ↔ 2Pb2+. Notably, the majority of the trace-element concentrations gradually decrease in the order LL → UL except Fe, Co, Cu, and Ge, while Fe, In, and Sn in sphalerite and Ag and Sb in galena have the highest concentration in the VL, indicating that the VL is a secondary migration channel for the ore-forming fluids. Furthermore, the trace-element compositions of the sulfides in the Maozu Pb-Zn deposit are consistent with the typical MVT deposit (hosted in the carbonate sequence) but are markedly different from sedimentary exhalative (SEDEX), volcanogenic massive sulfide (VMS) and skarn-type deposits. Based on these results, as well as the geological and geochemical characteristics of the deposit, the Maozu Pb-Zn deposit is an MVT deposit.

Revealing weathering, diagenetic and provenance evolution using petrography and geochemistry: A case of study from the Cretaceous to Cenozoic sedimentary record of the SE Chaco-Paraná basin in Uruguay

The Cretaceous rift to post-rift sedimentary sequences of the Paraná Basin and the Cenozoic sedimentary cover reflect the paleoclimate and tectonic influence on weathering and diagenesis, allowing to constrain provenance components. Detailed petrography enhanced by SEM and XRD, along with geochemistry of major, trace and rare earth elements provide a unique multi-technique approach. Weathering and diagenesis of the Arapey, Guichón, Fray Bentos and Salto formations are depicted. Provenance components of each of these units are deciphered. Implications regarding the poral system are evaluated in the context of the Salto Aquifer. The feldsphatic litharenites interlayered within the flood basalts of the Arapey Formation of Early Cretaceous age show a provenance from the NE mainly derived from the Precambrian felsic basement and basaltic rocks. Moderate Th/Sc ratio (1.3), low CIA (56) and low Th/U ratio (1.59) and strongly negative Eu/Eu* anomaly (0.65), among other geochemical proxies, indicate a wide compositional variation and low weathering of the source rocks under semiarid climatic conditions. Effective porosity is low because of an opaline and zeolitic cementation during early diagenesis. Up section, the lithic feldsarenites of the Guichón Formation (Late Cretaceous) are characterized by the dominance of volcanic and sedimentary lithoclasts. Low Th/Sc ratio (0.55) and CIA (56) values, moderate Th/U ratio (2.99) and Eu/Eu* negative anomaly (0.82) indicate the influence of local mafic source rock and low weathering under semiarid to wet climatic conditions. No effective porosity is preserved because of the smectitic matrix (11%) and of the calcitic cement. After a long period of erosion and no-deposition, the diamictites and wackes of the Fray Bentos Formation were deposited during the Oligocene. Angular fragments of basalts and arenites as lithoclasts, along with low Th/Sc ratio (0.52) and CIA values (58), moderate Th/U ratio (2.45) and Eu/Eu* negative anomaly (0.76) point to the influence of local sources probably related to tectonic uplift during deposition and scarce weathering. Well-developed calcretes indicate semiarid climatic conditions during burial, and porosity is only preserved after calcite dissolution. A braided fluvial environment was the depositional locus for the Pliocene Salto Formation. The arenites are dominated by rounded quartz, but the original clastic composition was modified due to strong dissolution processes that affected mainly the feldspar population. Low Th/Sc ratio (0.58), low to moderate CIA value (70), very low Th/U ratio (1.45) and moderately negative Eu/Eu* anomaly (0.82) confirm the influence of a mafic source. A wide range of variation of the Ce/Ce* anomaly (0.76–5.86), along with a high concentration of U, Cu, V, As are untypical geochemical characteristics for recycled quartz arenites indicating remobilization during early diagenesis rather than intense reworking. The porosity of the opal-free clastic rocks is extremely high, constituting an important local groundwater reservoir.

Effects of density and composition on the properties of amorphous alumina: A high-dimensional neural network potential study.

Amorphous alumina (a-AlOx), which plays important roles in several technological fields, shows a wide variation of density and composition. However, their influences on the properties of a-AlOx have rarely been investigated from a theoretical perspective. In this study, high-dimensional neural network potentials were constructed to generate a series of atomic structures of a-AlOx with different densities (2.6 g/cm3-3.3 g/cm3) and O/Al ratios (1.0-1.75). The structural, vibrational, mechanical, and thermal properties of the a-AlOx models were investigated, as well as the Li and Cu diffusion behavior in the models. The results showed that density and composition had different degrees of effects on the different properties. The structural and vibrational properties were strongly affected by composition, whereas the mechanical properties were mainly determined by density. The thermal conductivity was affected by both the density and composition of a-AlOx. However, the effects on the Li and Cu diffusion behavior were relatively unclear.

Partial Melting of the Lower Oceanic Crust: Implications for Tracing the Slab Component in the Source of Mid‐Ocean Ridge Basalts

AbstractThe potential role of the lower oceanic crust in the source region of mid‐ocean ridge basalts has been examined by a series of partial melting experiments on three natural pyroxenite xenoliths entrained in alkali basalts well representing the lower oceanic crustal material at 1 GPa, 1100–1300°C. Layered experiments were also performed to simulate the reaction between lower oceanic crust‐derived melts and surrounding dunite and have successfully enabled the melt infiltration. Melt compositions are consistently basaltic and vary significantly as a function of melt fraction, and these lower oceanic crust‐derived melts are characterized by high Eu/Eu*, Nb/Ta, and Ba/Th values, especially for experiments conducted at 1300°C. No reaction zone is observed in layered experiments, and our results demonstrate that the compositional variations caused by the reaction with dunitic mantle in the lower oceanic crust‐derived melts are relatively minor at 1 GPa. Our melting experiments show that melting of the lower oceanic crust can provide trace element characteristics such as positive Sr and Eu anomalies and consistent Nb/Ta and Zr/Hf ratios, but it cannot account for the wide major element compositional variations (e.g., high FeOT and TiO2 contents) in mid‐ocean ridge basalt (MORB). Some component other than the surrounding dunite in the upwelling mantle flux is needed to substantially modify the major element compositions of the lower oceanic crust‐derived melts. It is quite likely that these lower oceanic crust‐derived melts could be extracted from the upwelling mantle while still preserving their trace element and isotopic imprintings.

Emission and level population in noble gases and their binary mixtures under ion beam excitation

The luminescence spectra for noble gases and their binary mixtures excited by Ar ions with energies up to 70 MeV were examined in the range of 200–980 nm. The emissions at the transitions of heteronuclear ionic molecules ArXe+, ArKr+, KrXe+ were studied for a gas-mixture, with a wide variation in the percentage composition. The noble gases atomic spectra are dominated by lines of (n + 1)p-(n + 1)s-transitions (2p-1s in Pashen’s notation); lines of d-(n + 1)p-transitions were also observed. The distribution of radiation over 2p-levels of noble gas atoms was also measured. The sharp predominance of the fraction of radiation from the levels 2p2 of Ar, 2p6 of Kr and 2p5 of Xe is partially explained by the relatively small values of the rate constants for the deactivation of these levels, by own atoms. The mechanisms of levels population under the excitation of noble gases by ionizing radiation are discussed.

Transformation of PGM in supra subduction zones: Geochemical and mineralogical constraints from the Veria (Greece) podiform chromitites

Extremely abundant PGE-minerals (PGM) hosted in chromitites from the Veria ophiolite complex in Macedonia (N. Greece) may be unique among ophiolite complexes. This study focuses on differences between the low- and high-PGE chromitites. New textural, mineralogical and geochemical constraints from those ores are presented, aiming to define factors controlling the PGE enrichment in a supra subduction environment, in the light of post-magmatic processes. The whole ore analyses for mmajor and trace elements indicated an unusually high-IPGE content (up to 25 ​ppm) and higher Fe, Ca, Mn, Zn and V contents in high-PGE compared to low-PGE in massive chromitites. The wide compositional variation of chromite, even in the same polished section, the occurrence of very fine PGM (less than 20 ​μm) as inclusions within chromite and extremely large (>1000 ​μm), angular or fine-grained PGM aggregates ones within a matrix of highly fragmented chromite - Cr-garnet matrix, may indicate crystallization/recrystallization of chromite from more than one precursor phases. Laurite (RuS2) is very limited, occurring as remnants surrounding by Ru–Os–Ir oxides/hydroxides, of a wide compositional variation. Irarsite occurs as euhedral crystals up to 200 ​μm, surrounding by chromite, as anhedral exsolutions 1–200 ​μm within laurite, or creating segregates with platarsite and relics of (Ru, Pt, Rh, Os) sulfarsenides. Platinum–Ru–Rh–Pd-minerals occur commonly as relatively fine-grained assemblages, up to 50 ​μm, along with irarsite and other relics of (Ru, Pt, Rh, Os) sulfarsenides. Pt-alloys show a variation ranging from tetraferroplatinum to Pt–Ir–Fe–Ni alloys. The presence of laurite relics in large IPGM, awaruite, heazlewoodite, and carbon-bearing material reflecting a super-reducing environment, and the transformation of primary PGM into Os–Ir–Ru-alloys and oxides/hydroxides in association with Fe-chromite and Fe3+-bearing garnet (andradite-uvarovite solid-solution series) may reflect changes of the redox conditions from reducing to oxidizing. The relatively high Na content in hydrous mineral inclusions within high-PGE chromitites suggest a hydrous mantle source and provide the possibility for estimation of the P (average 3.0 ​kbar) and T (average 874 ​°C), indicating formation at a shallow mantle environment.