A New Approach to Characterizing Deposit Type Using Mineral Inclusion Assemblages in Gold Particles

Mineral inclusions within native gold are features of lode gold occurrences that are preserved in detrital particles. Inclusion assemblages in populations of gold particles in placers from specific localities are revealed through inspection of polished sections, and assimilation of robust data sets permits reconstruction of the lode source mineralogy. Inclusion assemblages differ considerably according to the source deposit type, and various approaches have been employed to graphically represent inclusion mineralogy. We present a simple method for depicting and comparing inclusion assemblages using a single standardized radar diagram template that illustrates the proportions of 11 metal and 5 nonmetal (and metalloid) elements in each inclusion assemblage. The Canadian Cordillera hosts many different gold-bearing deposit types and is an ideal terrane in which to develop a globally applicable methodology. Although placer gold is widespread, the location and nature of source mineralization is commonly unclear. This study is based on the inclusion suites recorded in 37 sample sets of gold particles from both placer and lode localities. Radar diagrams describing inclusion assemblages show clear generic differences according to deposit type. Diagnostic signatures have been established and act as templates against which samples of unknown origin may be compared. This approach permits differentiation between populations of gold particles formed in different magmatic systems (low-sulfidation epithermal, calc-alkalic porphyry, and alkalic porphyry), which may all be distinguished from gold formed in orogenic (amagmatic) mineralization. Metallic element signatures are most useful in differentiating gold from different magmatic hydrothermal systems, whereas nonmetallic elements allow for classification of orogenic gold subtypes. Comparisons of mineral inclusion signatures from gold in the Canadian Cordillera with samples from similar geologic settings worldwide suggest that this approach to gold fingerprinting is globally applicable. Therefore, the geochemical signatures of inclusion assemblages provide a robust indication of deposit type and may be applied in exploration to illuminate regional metallogeny in areas where relationships between placer deposits and their source(s) may be unclear.

Excretion Patterns of Urinary Sediment and Supernatant Podocyte Biomarkers in Patients with Chronic Kidney Disease

Background: Podocyte depletion causes glomerulosclerosis, and persistent podocyte loss drives progression to end-stage kidney disease. Urinary sediment podocyte (u-sed Pod) mRNA excretion and urinary supernatant podocyte (u-sup PCX) protein have been used to monitor disease activity in glomerular diseases. However, the differences in these markers among pathologies have not been investigated. We examined the roles of these markers in kidney diseases. Methods: From January 2013 to March 2016, early morning urine samples were collected from 12 healthy controls and 172 patients with kidney disease (minor glomerular abnormality with mild proteinuria and/or microscopic hematuria, n = 15; minimal change nephrotic syndrome [MCNS], n = 15; membranous nephropathy [MN], n = 15; IgA nephropathy [IgAN], n = 60; crescentic glomerulonephritis [Cres GN], n = 19; lupus nephritis [LN], n = 10; others, n = 38). We examined u-sed Pod mRNA excretion, u-sup PCX protein and the urinary protein:creatinine ratio (u-PCR). Results: U-sed Pod mRNA excretion was significantly correlated with u-sup PCX protein (r = 0.37, p < 0.001). Both u-sed Pod mRNA excretion and u-sup PCX protein were significantly correlated with u-PCR (r = 0.53, p < 0.001 and r = 0.35, p < 0.001, respectively). Interestingly, u-sed Pod mRNA excretion was significantly increased in proliferative-type glomerulonephritis-including IgAN with extracapillary proliferative lesions, Cres GN and LN class IV-and significantly correlated with the rate of crescent formation, whereas u-sup PCX protein was significantly increased only in MN and subepithelial dense deposit-type LN compared with controls. Conclusions: Higher u-sed Pod mRNA excretion and u-sup PCX protein were associated with proliferative-type glomerulonephritis indicating podocyte detachment and subepithelial dense deposit-type glomerulonephritis, respectively. The results suggest that u-sed Pod mRNA excretion and u-sup PCX protein have usefulness for the diagnosis and measurement of disease activity with regard to glomerular diseases.

Geochemical - geology characteristics implicating original sources and copper - deposit type in Kon Ra ore - field

Based on the research results on petrographic - mineralogical characteristics, tectonic structural features, geochemistry of major and trace elements of the bedrock, alternative rock, ore, soil, mineralogical geochemistry, mineral facies, inclusions, the origin of ore formation related to oxidized granite and skarnoid - typed metasomatic process in Kon Ra copper ore field have been identified. Petrological and mineral characteristics indicate the process of transitional metasomatism between the skarn and hornfels, also known as bimetasomatic stage (skarnoid deposit type). Diopxite represents the Progade skarnoid stage. Tremolite, actinolite, quartz, chlorite, magnetite, molybdenite, less of chalcopyrite, pyrrhotite, and pyrite indicate the retrogade skarnoid stage. The following is sulfide - quartz stage (major minerals include: quartz, chalcopyrite, pyrite, pyrrhotite, molybdenite). This result is also consistent with the formation temperature 210÷270 0C and the geochemical zoning of elements from intrusive blocks through the outer contact zone that contains the ore and surrounding rocks are as follows: Cu, Zn, Ca (the zone has lime-rich formations), Fe3+, Mo increases in the outer contact zone containing ore closed to acid intrusive rocks. Inversely, the ratios of Pb/Cu, Zn/Cu, and As content increased in the alteration from this zone to the outer one. In addition, uranium mineralization is associated with a later magma stage (pegmatite granite in endo-contact is high uranium radiation: U = 0.17÷0.2%, 3,420,000÷8,020,000 µR/h and contains uraninite).

Geochemical exploration for buried sandstone-hosted uranium mineralisation using mobile U and Pb isotopes: case study of the REB deposit, Great Divide Basin, Wyoming

Mobile radiogenic lead isotopes (206Pb, 207Pb, 208Pb, and 210Pb) represent products of radioactive decay of their parental uranium and thorium isotopes (238U, 235U, 232Th), and are considered potential geochemical pathfinders of the buried sandstone-type uranium deposits. Soil samples collected along a geochemical traverse intersecting buried uranium roll front mineralisation at the REB deposit in the Great Divide Basin, Wyoming, USA were studied. Mineralisation of this deposit is hosted in weakly lithified arkosic sands, at a depth of 120 - 200 metres, without a strong surficial expression of its presence at depth which makes discovery of this deposit type difficult, slow, and expensive. All soil samples have been analysed for ratios of the mobile long-lived Pb isotopes and their parental U and Th isotopes, determined from partial leach products obtained using a weak acid leaching technique. The samples were also analysed for trace elements, assayed both in the partial leach products and using conventional whole soil sample assays. Ratios of the mobile radiogenic Pb isotopes to their parental U and Th isotopes (206Pb/238U, 207Pb/235U and 208Pb/232Th) determined in the partial leach products exhibit anomalous contents in the soil samples collected above the uranium rolls. The anomalous values are several times greater than background values, to lateral distances of 350-400m outside of the roll fronts. Notably, conventional whole soil assays have failed to detect the anomalies which were detected using mobile Pb isotopes. Supplementary material:https://doi.org/10.6084/m9.figshare.c.5610980

Mineralogical - geochemical characteristics of gold mineralization and its potential in the Tuong Duong area, Nghe An province

Tuong Duong area, Nghe An province is considered as a high potential area of gold deposits such as the Yen Na - Yen Tinh, Ban Bon, Xieng Lip, and Na Khom gold occurrences. Based on synthesizing, geological processing data, analysis and complement of the 15 thin sections, 10 thick sections, 02 scanning electron microscope and 05 ICP - MS samples, results show that the gold mineralization has fomed from hydrothermal activities at low - moderate temperature, belonging to quartz - sulfur - gold mineral deposit type. The gold contents in orebodies vary from medium to high values, with average contents ranging from 0.8÷6.55 (g/ton). Results also provide an overview of the prospect of gold resources, serving as a basis for determining the Au prospective areas in Tuong Duong, Nghe An province. The direct calculation method for metallization parameters and Huvo methods are applied in this paper to estimate gold resources in the study area, resulting in 2.21 tons of Au - metal.

Terrestrial Dissolved Organic Matter Mobilized From Eroding Permafrost Controls Microbial Community Composition and Growth in Arctic Coastal Zones

Climate warming is accelerating erosion along permafrost-dominated Arctic coasts. This results in the additional supply of organic matter (OM) and nutrients into the coastal zone. In this study we investigate the impact of coastal erosion on the marine microbial community composition and growth rates in the coastal Beaufort Sea. Dissolved organic matter (DOM) derived from three representative glacial deposit types (fluvial, lacustrine, and moraine) along the Yukon coastal plain, Canada, were used as substrate to cultivate marine bacteria using a chemostat setup. Our results show that DOM composition (inferred from UV-Visible spectroscopy) and biodegradability (inferred from DOC concentration, bacterial production and respiration) significantly differ between the three glacial deposit types. DOM derived from fluvial and moraine types show clear terrestrial characteristics with low aromaticity (Sr: 0.63 ± 0.02 and SUVA254: 1.65 ± 0.06 L mg C−1 m−1 &amp; Sr: 0.68 ± 0.01 and SUVA254: 1.17 ± 0.06 L mg C−1 m−1, respectively) compared to the lacustrine soil type (Sr: 0.71 ± 0.02 and SUVA254: 2.15 ± 0.05 L mg C−1 m−1). The difference in composition of DOM leads to the development of three different microbial communities. Whereas Alphaproteobacteria dominate in fluvial and lacustrine deposit types (67 and 87% relative abundance, respectively), Gammaproteobacteria is the most abundant class for moraine deposit type (88% relative abundance). Bacterial growth efficiency (BGE) is 66% for DOM from moraine deposit type, while 13 and 28% for DOM from fluvial and lacustrine deposit types, respectively. The three microbial communities therefore differ strongly in their net effect on DOM utilization depending on the eroded landscape type. The high BGE value for moraine-derived DOM is probably caused by a larger proportion of labile colorless DOM. These results indicate that the substrate controls marine microbial community composition and activities in coastal waters. This suggests that biogeochemical changes in the Arctic coastal zone will depend on the DOM character of adjacent deposit types, which determine the speed and extent of DOM mineralization and thereby carbon channeling into the microbial food web. We conclude that marine microbes strongly respond to the input of terrestrial DOM released by coastal erosion and that the landscape type differently influence marine microbes.

Permafrost-derived dissolved organic matter character controls microbial community composition in Arctic coastal waters

&lt;p&gt;Climate warming is accelerating erosion rates along permafrost-dominated Arctic coasts. To study the impact of erosion on marine microbial community composition and growth in the Arctic coastal zone, dissolved organic matter (DOM) from three representative glacial landscapes (fluvial, lacustrine and moraine) along the Yukon coastal plain, are provided as substrate to marine bacteria using a chemostat setup. Our results indicate that chemostat cultures with a flushing rate of approximately a day provide comparable DOM bioavailability estimates to those from bottle experiments lasting weeks to months. DOM composition (inferred from UV-Visible spectroscopy) and biodegradability (inferred from DOC concentration, bacterial production and respiration) significantly differed between the three glacial deposit types. DOM from fluvial and moraine deposit types shows more terrestrial characteristics with lower aromaticity (S&lt;sub&gt;R&lt;/sub&gt;: 0.63 (&amp;#177;0.02), SUVA&lt;sub&gt;254&lt;/sub&gt;: 1.65 (&amp;#177;0.06) respectively S&lt;sub&gt;R&lt;/sub&gt;: 0.68 (&amp;#177;0.00), SUVA&lt;sub&gt;254&lt;/sub&gt;: 1.17 (&amp;#177;0.06)) compared to the lacustrine deposit type (S&lt;sub&gt;R&lt;/sub&gt;: 0.71 (&amp;#177;0.02), SUVA&lt;sub&gt;254&lt;/sub&gt;: 2.15 (&amp;#177;0.05)). The difference in composition of DOM corresponds with the development of three distinct microbial communities, with a dominance of Alphaproteobacteria for fluvial and lacustrine deposit types (relative abundance 0.67 and 0.87 respectively) and a dominance of Gammaproteobacteria for moraine deposit type (relative abundance 0.88). Bacterial growth efficiency (BGE) is 66% for moraine-derived DOM, while 13% and 28% for fluvial-derived and lacustrine-derived DOM respectively. The three microbial communities therefore differ in their net effect on DOM utilization. The higher BGE value for moraine-derived DOM was found to be due to a larger proportion of labile colourless DOM. The results from this study, therefore indicate a substrate control of marine microbial community composition and activities, suggesting that the effect of permafrost thaw and erosion in the Arctic coastal zone will depend on subtle differences in DOM related to glacial deposit types. These differences further determines the speed and extent of DOM mineralization and thereby carbon channelling into biomass in the microbial food web. We therefore conclude that marine microbes strongly respond to the input of terrestrial DOM released during coastal erosion of Arctic glacial landscapes.&lt;/p&gt;

Trace element geochemistry of iron oxides from the Per Geijer apatite iron ores in the Kiruna district, northern Sweden: Implications for ore genesis

&lt;p&gt;Iron oxide-apatite (IOA) deposits are an important source of iron ore based on the modal abundance of magnetite &gt; 90 vol.%. Further interest is generated due to the high variability of apatite and hematite in some of these ores. The origin of the so-called Kiruna-type deposits has been subject to controversy for more than a century. Models range from a purely magmatic origin to ore-forming processes that involve variable stages of hydrothermal fluid involvement to a not widely accepted sedimentary-exhalative origin. In contribution of understanding ore-forming processes of this deposit type, we performed mineral chemistry and trace element analyses on samples from the Per Geijer deposits. They account for the lesser studied deposits in the Kiruna district of northern Sweden. A comprehensive mineral-chemical dataset of magnetite and hematite obtained by electron microprobe analysis (EPMA) and LA-ICP-MS from representative drill core samples is presented. Magnetite and four different types of hematite constitute the massive orebodies: Primary and pristine magnetite with moderate to high concentrations of Ti (&amp;#8764;61&amp;#8211;2180 ppm), Ni (&amp;#8764;11&amp;#8211;480 ppm), Co (&amp;#8764;5&amp;#8211;300 ppm) and V (&amp;#8764;553&amp;#8211;1831 ppm) indicate a magmatic origin for magnetite. Hematite type I appears as a replacement of magnetite with high Ti (&amp;#8764;15,700&amp;#8211;42,300 ppm), relatively constant V (&amp;#8764;1460&amp;#8211;2160 ppm) and moderate Sn (&amp;#8764;29&amp;#8211;105 ppm) concentrations. Moderate and variable Ti (&amp;#8764;369&amp;#8211;12,490 ppm) and low Sn (&amp;#8764;1.4&amp;#8211;19 ppm) concentrations are representative for hematite type II. Hematite type III has lowest Ti (&amp;#8764;99&amp;#8211;1250 ppm) concentrations. Significantly high Ti concentrations (&amp;#8764;12,100&amp;#8211;78,700 ppm), low V (&amp;#8764;132&amp;#8211;381 ppm) and high Sn (&amp;#8764;129&amp;#8211;456 ppm) concentrations account for type IV. The presence of fluorapatite and disseminated pyrite with high Co:Ni ratios (&gt; 1&amp;#8211;10) in massive magnetite ores are consistent with a high temperature (&amp;#8764; 800&amp;#176;C) genesis for the deposit. The different and abundant types of hematite state subsequent hydrothermal events.&lt;/p&gt;

Key factors influencing earthquake-induced liquefaction and their direct and mediation effects

Many factors impact earthquake-induced liquefaction, and there are complex interactions between them. Therefore, rationally identifying the key factors and clarifying their direct and indirect effects on liquefaction help to reduce the complexity of the predictive model and improve its predictive performance. This information can also help researchers understand the liquefaction phenomenon more clearly. In this paper, based on a shear wave velocity (Vs) database, 12 key factors are quantitatively identified using a correlation analysis and the maximum information coefficient (MIC) method. Subsequently, the regression method combined with the MIC method is used to construct a multiple causal path model without any assumptions based on the key factors for clarifying their direct and mediation effects on liquefaction. The results show that earthquake parameters produce more important influences on the occurrence of liquefaction than soil properties and site conditions, whereas deposit type, soil type, and deposit age produce relatively small impacts on liquefaction. In the multiple causal path model, the influence path of each factor on liquefaction becomes very clear. Among the key factors, in addition to the duration of the earthquake and Vs, other factors possess multiple mediation paths that affect liquefaction; the thickness of the critical layer and thickness of the unsaturated zone between the groundwater table and capping layer are two indirect-only mediators, and the fines content and thickness of the impermeable capping layer induce suppressive effects on liquefaction. In addition, the constructed causal model can provide a logistic regression model and a structure of the Bayesian network for predicting liquefaction. Five-fold cross-validation is used to compare and verify their predictive performances.