Enrichment Of Elements Research Articles

Post-orogenic magmatic-hydrothermal system in the southern Songpan-Ganze Orogen, eastern Tibetan Plateau

ABSTRACT Post-orogenic magmatism is uncommon in the Songpan-Ganze Orogen (SGO), and could provide deep insights into geodynamic evolution and related metallogenesis. Here we present zircon U-Pb-Hf isotopes and whole-rock geochemical data, for post-orogenic granitoids newly identified in the southern SGO. The Longxigou and Yangfanggou granites yield crystallization age of ca. 165 Ma and εHf(t) values of +3.8 to −9.1. This age post-dates regional ca. 220–200 Ma orogenic magmatism and ca. 205–190 Ma peak metamorphism, and corresponds to ca. 200–150 Ma post-orogenic magmatism which is exemplified by neighbouring and coeval Wenjiaping and Wulaxi felsic plutons. They are crosscut by ca. 133 Ma granitic pegmatites, with εHf(t) values of −4.3 to −14.2. These post-orogenic granites show high SiO2 contents, as well as low Mg# values, (Zr + Nb + Ce + Y) concentrations and zircon saturation temperatures. They have continental crust-like REE patterns and trace element profiles, and exhibit negative Eu anomalies, enrichment in large ion lithophile elements and depletion in high field strength elements. Their mineral assemblages lack typical high-temperature (e.g. pyroxene and fayalite) and peraluminous (e.g. garnet and cordierite) varieties. All these features indicate an I-type granite affinity, and a dominant derivation from thickened lower crust. In comparison, these post-orogenic granites are compositionally distinct from regional late-orogenic (>200 Ma) categories, which have more positive εHf(t) values and higher Mg# values, with subduction-related signatures involving significant mantle components. Further, several high-grade stratiform Cu deposits and a tungsten deposit occur to the south of these granitic plutons, and have mineralization ages of 164–151 Ma together with biotite alteration age of ca. 134 Ma. Hence, ca. 165–133 Ma magmatic-hydrothermal system was most likely responsible for Cu-W mineralization and effective upgrading of metal deposits in the southern SGO.

Arc building and maturation of the Lombok Island, East Sunda Arc

Intra-oceanic subduction zones are major sites of crust–mantle material exchange and crustal growth; however, the processes responsible for the magmatic evolution and transformation of nascent arcs into mature oceanic arcs with thicker crust are debated. We present mineral chemistry, zircon UPb age and Hf isotopic data, and whole-rock chemical and Sr–Nd–Hf–Pb isotopic data for Cenozoic volcanic rocks on Lombok in the East Sunda Arc, Indonesia, to investigate their petrogenesis and arc maturation. SIMS zircon UPb analyses of lavas from southern Lombok yield an early Oligocene age of ∼30 Ma. The lavas can be divided into three groups based on their ages and geochemical characteristics: group I (late Eocene) and II (∼30 Ma) lavas from southern Lombok, and group III lavas (∼3–0 Ma) from northern Lombok. The lavas are characterized by a progressive enrichment in K2O and incompatible element contents, and NdHf isotopic compositions with time. Group I lavas are tholeiitic basalts with low K2O contents (0.15–0.17 wt%) and Indian-MORB like rare earth element (REE) patterns and NdHf isotopic compositions (εNd = +7.4; εHf = +14.5), enrichment in large-ion lithophile elements (e.g., Rb, U, and K), and typical forearc basalt (FAB) geochemical characteristics. Group II lavas are low-K basaltic andesites to dacites that yield flat chondrite-normalized REE patterns [(La/Sm)N = 0.9–1.4], uniform initial 87Sr/86Sr ratios (0.7038–0.7042), and positive εNd(t) (+5.9 to +6.8) and εHf(t) (+13.9 to +14.4) values. Group III lavas are typically medium- to high-K calc-alkaline basalt to andesite and are enriched in light REEs [(La/Sm)N = 1.6–3.3] with uniform initial 87Sr/86Sr ratios (0.7038–0.7042) and slightly low εNd(t) (+3.9 to +5.4) and εHf(t) (+10.5 to +12.5) values. Progressive enrichment in incompatible element contents and NdHf isotopic compositions over time, from FAB to high-K calc-alkaline lavas, reflect the maturation of the East Sunda Arc. Sr–Nd–Pb–Hf isotopic mixing models, along with trace element ratios (e.g., Ba/Th, La/Yb, Th/Yb), suggest that increasing amounts of sediments were incorporated into the mantle sources of the magmas from group I (∼0%) to group II (<0.5%) and group III (0.5%–1.0%) lavas. Partial melting models show that the formation of group I and II lavas can be reproduced by high-degree (∼10%) partial melting of spinel peridotite, whereas the group III lavas were formed by low-degree (∼5%) partial melting of spinel peridotite. We propose that the evolution of Lombok arc magmas was controlled mainly by the fluxes of subducted slab material, along with decreasing degrees of partial melting as a result of crustal thickening over time.

Barium-Mg isotopes in high Ba-Sr granites record a melt-metasomatized mantle source and crustal growth

High Ba-Sr granites are geochemically distinct from the more familiar I-, S- and A-types (of igneous, sedimentary or anorogenic/anhydrous/alkaline parentage), in particular by their lack of depletion in Ba and Sr relative to other large-ion lithophile elements (LILE). These differences are sufficient enough to indicate different petrogenetic processes which are still the subject of considerable debate. High Ba-Sr plutons from the classic Caledonian type location in NW Scotland show a range of elemental and isotopic enrichment, ideal for novel petrogenetic investigations such as the application of “non-traditional” stable isotope systems. Two directly comparable plutons have been analysed for Ba and Mg isotopes, from either end of the range of enrichment. Barium isotopes (δ138/134Ba values of −0.05 to +0.23 ‰ in the relatively “depleted” Strontian pluton and −0.19 to +0.03 ‰ in the enriched Rogart comparator) overlap normal mantle values but extend to lighter compositions, consistent with addition of up to 5 % pelagic sediment that has incorporated variable amounts of biogenic barite. Magnesium isotopes (δ26Mg values of −0.30 to −0.25 ‰ versus −0.42 to −0.23 ‰ in Strontian and Rogart, respectively) lie largely within the normal mantle range, with two light outliers possibly indicative of carbonate involvement but for which fractional crystallization cannot be excluded. Associated relationships between fluid-mobile and melt-mobile elements suggest that sediment melting transfers the crustal isotope signature to a dominantly mantle source, itself variable between isotopically depleted mantle wedge and previously enriched lithospheric mantle. The combined Ba, Mg, O, Sr, and Nd isotope and elemental data are all consistent with a small percentage of pelagic sediment in a mantle source for high Ba-Sr granites, and this is sufficient to disguise these essentially mantle-derived rocks as reworked continental crust. First-order estimates suggest that some 10 % of granites worldwide may have high Ba-Sr character, although the proportion of these that represent largely juvenile origin is currently unknown. Nevertheless, as compositional equivalents of Archean sanukitoids, they may represent unrecognized mantle contributions to crustal growth over some 3 billion years of Earth history.

Indigenous microbial influence on REE enrichment and fractionation in South China weathering crusts: Insights from experimental simulations

The activity of microorganism plays an important role on the enrichment, migration and fractionation of rare earth elements (REEs) in the supergene environment. To investigate the characteristics of indigenous microorganisms on the enrichment and fractionation of REEs, we studied the adsorption efficiencies of REEs by 30 indigenous microbial strains that were isolated and cultured from the weathering profile of a regolith-hosted REE deposit in South China. Most microbial strains exhibited high adsorption efficiencies for REEs, ranging from 2.3 to 42.9 mg g−1. Notably, the taxonomic classification of microorganisms significantly influenced the adsorption selectivity. Gram-positive bacteria exhibited a pronounced enrichment of the heavy REEs, while gram-negative bacteria showed no obvious adsorption preference. The tetrad effects were observed in REE adsorption patterns of gram-negative bacteria and fungi; however, fungi demonstrated a much higher affinity for light and medium REEs. Chemically modified microbial cells were employed to investigate the adsorption mechanism, revealing that distinct functional groups of microbial cells corresponded to the adsorption preference of microorganisms towards REE. Carboxyl and phosphate groups contributed to a relatively high adsorption capacity for light REEs and heavy REEs, respectively. The findings of our study suggest that the distinct composition of microbial groups may exert a significant influence on the biogeochemical cycle of REE in weathering profiles.

TEENA: an integrated web server for transposable element enrichment analysis in various model and non-model organisms.

Transposable elements (TEs) are abundant in the genomes of various eukaryote organisms. Increasing evidence suggests that TEs can play crucial regulatory roles-usually by creating cis-elements (e.g. enhancers and promoters) bound by distinct transcription factors (TFs). TE-derived cis-elements have gained unprecedented attentions recently, and one key step toward their understanding is to identify the enriched TEs in distinct genomic intervals (e.g. a set of enhancers or TF binding sites) as candidates for further study. Nevertheless, such analysis remains challenging for researchers unfamiliar with TEs or lack strong bioinformatic skills. Here, we present TEENA (Transposable Element ENrichment Analyzer) to streamline TE enrichment analysis in various organisms. It implements an optimized pipeline, hosts the genome/gene/TE annotations of almost one hundred species, and provides multiple parameters to enable its flexibility. Taking genomic interval data as the only user-supplied file, it can automatically retrieve the corresponding annotations and finish a routine analysis in a couple minutes. Multiple case studies demonstrate that it can produce highly reliable results matching previous knowledge. TEENA can be freely accessed at: https://sun-lab.yzu.edu.cn/TEENA. Due to its easy-to-use design, we expect it to facilitate the studies of the regulatory function of TEs in various model and non-model organisms.

Hydrogeochemical characteristics and enrichment regularities of groundwater uranium in the Erlian basin, China

Groundwater is a key medium for the migration and enrichment of elements into ore bodies in sandstone-type uranium deposits, with anomalies of uranium elements and their associated components in water serving as indicators for exploring such deposits. The Erlian Basin, located in central-northern Inner Mongolia, is a crucial production area for sandstone-type uranium deposits in China. The groundwater flow system in the basin plays a significant role in the formation of uranium deposits. To study the hydrogeochemical characteristics and enrichment regularities of groundwater uranium in the Erlian Basin, 269 groundwater samples were collected. Hydrogeochemical analysis methods, such as Piper diagrams, Gibbs diagrams, and contour maps, were employed to determine the distribution characteristics and occurrence forms of groundwater uranium in the study area. The primary water chemistry types in the study area were HCO3–Ca•Na, HCO3–Na, HCO3•SO4–Na, and SO4•HCO3–Na•Ca. The distribution range of uranium content in groundwater in the study area was 0.1–453 μg/L (average of 53.08 μg/L). A comprehensive analysis, based on the direction of groundwater flow and changes in the redox environment, suggested that the higher uranium values in groundwater were distributed in the runoff and discharge areas, with uranium anomaly points existing in areas with alternating oxidation and reduction zones. These uranium anomaly points were in good agreement with the known large uranium deposits of Nuheting, Qiharigetu, Daoersu, and others, thereby predicting six other uranium hydrochemical anomaly points as prospective areas for uranium mineralization. The pH value distribution range in the study area's groundwater was 6.8–9.1, and the redox potential (Eh) value range was -126–52 mV, indicating that uranium exists in groundwater in the form of UO2(CO3)34− and UO2(CO3)22−. An increase in bicarbonate (HCO3−) is conducive to uranium dissolution. The enrichment and occurrence forms of uranium in groundwater are influenced by the concentrations of Fe and (Ca2++Mg2+), with uranium precipitation and enrichment occurring as the groundwater evolves and changes in the redox environment. The uranium content in deep wells is higher than in nearby shallow wells, indicating that deep water circulation is beneficial for mineralization. The pH, Eh, HCO3−, Fe, and other hydrogeochemical indicators are indicative of uranium enrichment; thus, they can be considered as reference bases when exploring for potential uranium resources.

Mineralogical Characteristics of Color-Changing Garnet and the Effect of Light Path Length on Color

The color-changing garnet displays the “alexandrite effect”, changing from green in daylight to purplish-red under incandescent light. The mineralogical characteristics of color-changing garnet is analyzed using Raman spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, an electron probe, and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). The color of garnets with different thicknesses was calculated using the International Commission on Illumination (CIE 1976) L*a*b* uniform color system. The results revealed the presence of rutile inclusions in color-changing garnet. Strong absorption in both the blue-violet zone and orange-yellow zone was the main cause for the color-changing effect of garnet. The distribution pattern of rare earth elements (REE) was left-leaning, showing the enrichment of heavy rare earth elements (HREE) and depletion of light rare earth elements (LREE). As the total Cr and V concentrations increased, the area of the 574 nm absorption peak in the UV-Vis spectrum also increased, leading to a more significant variation in color ΔE*ab. The light path length of the gemstone had a significant impact on the extent of the color-changing effect. The color difference reached a maximum and the color-changing effect was most visible when the thickness of the gemstone was 5 mm.

Effect of Genotype on Cadmium and Trace Element Accumulation in Wheat from Weakly Alkaline Cadmium-contaminated Soil.

Cadmium (Cd) contamination of farmland soils leads to Cd accumulation in crops and reduced micronutrient uptake, posing grave risks to food safety. Herein, we investigated the enrichment and transportation patterns of Cd and trace elements in different parts of six wheat genotypes grown in weakly alkaline Cd-contaminated soils via pot experiments. The results revealed that the wheat grain variety with high Cd accumulation (Ningmai13) demonstrated a 1.94-fold increase compared to the variety with low accumulation (Yanong0428). The transfer factor of Cd from wheat straw to grain ranged from 0.319 to 0.761, while the transfer factor of Cd from root to straw ranged from 0.167 to 0.461. Furthermore, the concentrations of other metals in wheat grains followed the order of Zn > Mn > Fe > Cu. There was a significant positive correlation between Cd and Mn in grains, indicating a potential synergistic effect. Overall, this study provides valuable insights into the regulation of micronutrient intake to modulate Cd uptake in wheat.

Maximum-scoring path sets on pangenome graphs of constant treewidth.

We generalize a problem of finding maximum-scoring segment sets, previously studied by Csűrös (IEEE/ACM Transactions on Computational Biology and Bioinformatics, 2004, 1, 139-150), from sequences to graphs. Namely, given a vertex-weighted graph G and a non-negative startup penalty c, we can find a set of vertex-disjoint paths in G with maximum total score when each path's score is its vertices' total weight minus c. We call this new problem maximum-scoring path sets (MSPS). We present an algorithm that has a linear-time complexity for graphs with a constant treewidth. Generalization from sequences to graphs allows the algorithm to be used on pangenome graphs representing several related genomes and can be seen as a common abstraction for several biological problems on pangenomes, including searching for CpG islands, ChIP-seq data analysis, analysis of region enrichment for functional elements, or simple chaining problems.

Enhancing deep orebody prediction and localization through the revelation of geochemical primary halo patterns in drill holes

Geochemical primary halos play a crucial role in mineral exploration as they provide valuable insights into the dispersion of ore materials, identification of concealed deposits, and determination of ore deposit dimensions. The Naruo mining area in the Duolong mineral district, northern Tibet, China well-known for its worldclass porphyry-epithermal Cu–Au deposits is currently chosen as the study area. We employ statistical and nonlinear methods to analyze geochemical data from drill holes. Specifically, R-type cluster analysis is utilized to evaluate element affinity and concentration index, while an improved Grigorian zoning index is employed to delineate the vertical zoning sequence of the primary halo. These methodologies significantly enhance our understanding of element enrichment within geological contexts and greatly contribute to mineral resource evaluation. Based on these results, we have constructed a vertical zonation index model of denudation coefficient tailored to the geological characteristics of mineralization within the study area. This model effectively represents the vertical variation of the ore body. Our findings reveal a decrease in this zoning index towards the central region of deep ore bodies which correlates with deep granodiorite porphyry occurrences. Furthermore, we observe increasing concentrations of Cu, Ag, and Au with depth in specific sections of drill holes indicating promising exploration potential. Supplementary short-wave infrared data suggests the presence of a deep hydrothermal center in drill hole RNZK2404 which tentatively infers concealed porphyry bodies. Notably, the reversal observed at 4200 m on RNZK2404's zoning index hints at a possible hidden ore body at great depths. Finally, three-dimensional visualization techniques effectively illustrate spatial patterns for elements thereby paving way for future endeavors in mineral exploration.

Hydrothermal enrichment of rare earth elements in the Lower Permian Lijiatian bauxite deposit, southern China

Bauxite deposits are an important source of Al and also host a variety of critical metals, including rare earth elements (REEs). However, the parent rocks of bauxite deposits generally have low REE contents, leading to uncertainty over the REE sources and enrichment mechanisms. In this study, we report high REE (2095 ppm; Ce = 1340 ppm) contents in the Lijiatian bauxite deposit in Luxi County, western Hunan Province, South China. The Lijiatian bauxite deposit is the largest deposit in Hunan Province, with a total Al resources exceeding 7 × 106 tons. The ore-bearing strata in the lower Permian Liangshan Formation (ca. 275 Ma) are comprised a 3–5-m-thick bauxite layer (bauxite ore/clay) and an underlying 4–8-m-thick Fe layer (Fe ore/Fe-rich clay). The high REE contents in the bauxites can be attributed to the widespread presence of bastnäsite. The bastnäsite commonly coexists with authigenic chlorite, which formed at temperatures of 221–285 °C, indicative of a hydrothermal origin. Uranium–Pb dating of the bastnäsite yielded an age of 141.4 ± 7.0 Ma, indicating a hydrothermal overprint occurred during the Early Cretaceous, which resulted in the enrichment of REEs in the bauxites. The high contents of REEs, Ba, and P in the Cambrian Niutitang Formation black shales indicate it was a potential source of these elements for bastnäsite and coexisting barite and apatite. The deep-seated hydrothermal fluids (enriched in HF, CO2, and H2S) associated with the late Yanshanian extensional tectonic event in South China (155–123 Ma) ascended along fractures. The ascending fluids interacted with the black shales, extracting REEs, Ba, and P. When the fluids reached a certain depth, they mixed with the infiltrating basinal waters to form a mineralising fluid. The fluid then migrated towards the bauxite layers, underwent cooling and depressurisation, and precipitated bastnäsite, barite, apatite, and chlorite. We propose that a hydrothermal event led to the enrichment of REEs in the bauxites in Hunan Province. Considering the scarcity of REEs in the parent rocks of bauxites worldwide, hydrothermal activity likely has a key role in REE enrichment in bauxites.

Evaluation of garnet phenocrysts in volcanic rocks (Görece/İzmir – Western Türkiye) for their usability as a semi-precious gemstone by multi-analytical methods

Garnets are observed as phenocrysts in blocky rhyolites of Cumaovası Volcanites and are reddish-blackish in color, show vitreous luster, and have dodecahedron forms varying between 0.5 and 2.0 cm in size. In optical microscope investigations, they exhibit fractured structures and contain quartz, hematite, chlorite, and acicular rutile inclusions. Garnet phenocrysts are highly consistent with spessartine-type garnet end members in the Raman spectrum. This result is supported by the mineral chemistry results determined as spessartine (Sps)0.50–0.52 almandine (Alm)0.47–0.48 grossular (Grs)0.01–0.02. In the chondrite, primitive mantle, and Mid-Oceanic Ridge Basalt normalized multi element variation diagrams, garnet phenocrysts show enrichment in all elements (except Sr, K, P, and Ti). In contrast, in the upper continental crust normalized multi element variation diagram, garnet phenocrysts show depletion in large ion lithophile elements (Rb, Ba, K, and Sr) relative to high field strength elements. They exhibit slight enrichment in light rare earth elements ((La/Sm)N = 0.11–1.07) relative to heavy rare earth elements ((Sm/Yb)N=0.78–0.97). Furthermore, garnet phenocrysts have significant negative europium (Eu) ((Eu/Eu*)N = 0.01–0.02) and mildly positive cerium ((Ce/Ce*)N = 2.43–13.77) anomalies indicating hot and reduced magma conditions. The Y/Ho ratios have ranged from 18.9 to 20.3 and are close to the chondrite value. The zircon saturation temperatures (TZr) of the garnet’s host rock was determined to be 756 °C. As a result of mineralogical, geochemical and gemological studies, it was concluded that Görece garnet phenocrysts have glassy luster and semi-transparent dodecahedral crystal shapes, so they can be classified as semi-precious gemstones. In addition, the rare earth element content of the garnet phenocrysts is similar to that of industrial garnet sands and it is thought that they may have potential.

Paleoclimatic and environmental conditions of the Lower-Middle Ordovician carbonate reservoir in the middle of Tarim Basin (NW China): Constrained by petrographic, geochemical, and carbon–oxygen isotopic characteristics

Breakthroughs have been made recently in the exploration of hydrocarbon in the middle of Tarim Basin, NW China. The complexity of the Lower-Middle Ordovician carbonate reservoir remains enigmatic and hinders the source, developmental mechanism of the calcite fills, and paleo-environmental conditions of the Yingshan and Yijianfang Formations have been unclear. Here we present the related paleoenvironmental settings and diagenetic history, using petrographic, geochemical, and carbon (13C) and oxygen (18O) isotopic characteristics of calcite fracture, cave, and fissure fillings of a Lower-Middle Ordovician carbonate reservoir. The results indicate that the limestone caves dominantly consist of CaO, FeO, and MgO, and minor quantities of TiO2 and MnO. Among the trace elements, Ni reported the highest values (with an average of 1162.16 ppm) and other trace elements such as Ba, V, and Ga occur in minor values (with an average of 71.03, 19.18, and 12.92 ppm) respectively. The enrichment of light rare earth elements (LREEs) over the heavy rare earth elements (HREEs), with positive and negative Ce, and negative Eu anomalies indicate the contexts of oxic and anoxic conditions in seawater and sediments interface. The variation in δ18OPDB values ranges from −4.72 to −14.48‰ (with an average of −10.12‰), indicating a setting of paleo-karstification by atmospheric freshwater dissolution. While the variation in δ13CPDB indicates relatively significant values, ranging between 0.82 to −3.80‰ (with an average of −1.07‰), suggests that the paleo-karstification in this region has experienced episodes of supergene and burial diagenesis. The paleo-temperature average value of 59.1 °C, and the paleo-salinity average (Z-value) of 120.07, indicating a relatively warm paleoclimatic environment during the development of calcite-filling deposits. The results suggest several paleo-environmental conditions when paleokarst occurred: a marine deposition environment, an atmospheric freshwater karstification environment, a shallow burial paleo-karstification environment, and a high-temperature deep-burial environment in Yingshan and Yijianfang Formation in the Shunbei area. This study serves as an analog for similar carbonate systems worldwide, providing valuable insights for understanding paleo-karstification processes in different tectonic and climatic settings. Comparative studies between the Shunbei area, Tarim Basin, and other carbonate platforms contribute to our knowledge of karst evolution and its implications for reservoir development and groundwater resources.

The giant Baerzhe rare-earth-element–Nb–Zr–Be deposit, Inner Mongolia, China, an Early Cretaceous analogue of the Strange Lake rare-metal deposit, Quebec

The Baerzhe deposit represents world-class mineralization of rare metals, in particular rare earth elements (REEs) and Nb, and shares mineralogical and geochemical similarities with the Strange Lake deposit in Canada. However, the mechanisms responsible for the rare-metal enrichment at Baerzhe are still under debate. Mineralization at Baerzhe is characterized by multiple stages of dissolution, re-precipitation and enrichment of rare-metal elements, as with the Strange Lake deposit. Zirconium was concentrated during magmatic fractionation of elpidite in a transsolvus agpaitic granite (Stage I), and was redistributed into zircon–quartz pseudomorphs during Na-metasomatism (Stage II). Rare earth elements, Nb and Be occur as a variety of mineral assemblages, mainly as pseudomorphs after complete replacement of unknown precursor minerals that are disseminated through the hematized transsolvus granites and were precipitated in three sequential stages (Stages III–V): Stage III is characterized by the mineralization of hingganite, aeschynite-(Y), columbite-(Fe) and euxenite-group minerals, accompanied by hematite alteration; the following Stage IV is defined mainly by monazite-(Ce) crystallization, and Stage V by the preceding REE minerals being replaced by light REE minerals (i.e. bastnäsite-(Ce) and fluocerite-(Ce)). The formation of various pseudomorphs as replacement for precursor minerals is also a common feature documented at Strange Lake. Our results call for a re-evaluation of the timing and role of meteoric waters at Baerzhe, which were suggested by previous researchers to have entered the ore-forming system prior to the mineralization of zircon. New in situ O isotopic analyses on pseudomorph-hosted mineral pairs and investigation of silicate melt–fluoride melt immiscibility through observations and analyses of melt inclusions could provide further insights into the nature of the Baerzhe system.

Позднемеловые-раннепалеогеновые вулканические породы Восточной Камчатки (особенности состава и изотопно-геохимическая гетерогенность)

New and previously published isotope-geochemical material on the Upper Cretaceous-Lower Paleogene volcanic complexes of the Ozernovsky-Valaginsky segment of the Achaivayam-Valaginsky paleoarc are presented. It is found that composition of rocks composing separate volcanic fields within the Achayvayam-Valagin paleoarc (terrane) is different. On Karaginsky Island, volcanics of the moderate-potassium calc-alkaline and shoshonite series are widespread. On Ozernaya Peninsula, low-potassium basalts of the tholeiitic series are predominantly developed. The rocks of the Kumroch Ridge include low-potassium basalt-basaltic andesite, medium-potassium calc-alkaline and high-potassium shoshonitic. Volcanic rocks of the Tumrok Ridge are represented by low-potassium picrites and high-potassium trachybasalt-trachyandesites. In the Valaginsky Ridge, low-potassium tholeiitic, moderate-potassium calc-alkaline and shoshonite-latite series, as well as picrites and lamproitoids are distinguished. Isotopic (Sr, Nd and Pb) and geochemical composition of the rocks indicate their formation from a depleted mantle source within an ensimatic volcanic arc. It is shown that in the absence of significant differences in the material composition of rocks, regional differences are manifested. It is suggested that large-ion lithophile elements enrichment of volcanics may relate to fluids introduced into the melts during the melting of the supra-subduction mantle wedge. Issues of geodynamics of the region are considered.

Solidification path and precipitation mechanism of a Ni-Cr-co-Mo based heat-resistant alloy

The solidification path and precipitation mechanism of the C-HRA-3 Ni-Cr-Co-Mo-based heat-resistant alloy are investigated by methods such as differential scanning calorimetry analysis, in-situ observations, quenching experiments, and scanning transmission electron microscopy. The results confirm that the primary solidification precipitates in the center of the C-HRA-3 alloy VAR ingot consist of Ti(C,N), M6C-M23C6 symbiotic phases, Ti(C,N)-M6C-M23C6 symbiotic phases and surrounding dispersed M6C and M23C6 carbides. The precipitation temperatures for Ti(C,N), M6C, and M23C6 are 1310 °C, 1280 °C, and 1230 °C, respectively. The C-HRA-3 alloy exhibits a wide solidification temperature range of 176 °C (1390 °C ∼ 1214 °C). Within 1390 °C ∼ 1355 °C, the γ phase grows vigorously, accompanied by a significant reduction in the fraction of liquid phase. At 1355 °C ∼ 1214 °C, the decrease in liquid phase fraction slows down, accompanied by significant enrichment of Mo, Cr, C and Ti elements. There is a clear functional relationship between the liquid phase percentage and temperature. M6C carbides undergo two heterogeneous nucleation mechanisms in the liquid phase. Due to the degradation of M6C carbides discharging Cr and C atoms, M23C6 carbides form at their edge. Dispersed M6C and M23C6 carbides nucleate at misfit dislocations around the symbiotic phases. Appropriately reducing the cooling rate during the stage above the precipitation temperature and increasing the cooling rate below the precipitation temperature can significantly reduce the volume percentage and size of the symbiotic phases.

After-effects of a closed copper mine: detailed analysis of environmental impacts in soil and plant samples

In several countries around the world, abandoned mining sites are blighted by pollution from metal and metalloids. Generated by mining processes, toxic pollutants have lasting effects on the ecosystem. The study examined the environmental impact of waste from a copper mine that was operated by the Caucasus Copper Limited Company between 1905 and 1928, revised and commissioned by Etibank in 1936, and ceased operations 75 years ago. Soil and plant samples (needles of Scotch pine, Pinus sylvestris L.) were collected from five specific regions around the mine and the levels of potentially toxic elements (PTEs) were determined, including As, Zn, Pb, Cd, Ni, Mn, Cr, Cu, Al, and Fe. The data obtained were used to calculate the enrichment factor (EF), geo-accumulation index (Igeo), contamination factor (CF), ecological risk index (ERI), human health risk index (BCF), and plant enrichment factor (EFPlant). In soil samples, the average EF values of certain elements such as As (453), Cu (59.9), Pb (30.7), Zn (5.26) were detected at high levels. However, average Igeo values indicate high pollution levels for As (8.25), Cd (6.72), Cu (4.94), Pb (4.33) and Zn (2.42), indicating the existence of serious ecological risks in the affected areas. Additionally, the average CF values indicate serious pollution levels from heavy metals such as As (1605), Cd (584), Pb (99.4), Cu (81.9), and Zn (14.6), highlighting the extensive pollution situation resulting from mining activities. Meanwhile, average ERI values indicate that Cd, As, Cu, and Pb pose serious ecological risks in the study areas.These PTEs were found in high concentrations in the waste tail and dump. Furthermore, the analysis determined that there was enrichment for Mn, Cd, Al, Cu, Pb, and Fe elements in plant samples. These PTEs have the potential to spread more widely depending on seasonal conditions and local topography. This situation demonstrates the need to measure metal and metalloids concentrations at certain times, taking into account the potential for environmental pollution of surface runoff water and underground resources in areas with high drainage potential from acid mines, such as at the Kuvarshan mine tailings site.

Discovery of genomic and transcriptomic pleiotropy between kidney function and soluble receptor for advanced glycation end products using correlated meta-analyses: The Long Life Family Study.

Patients with chronic kidney disease (CKD) have increased oxidative stress and chronic inflammation, which may escalate the production of advanced glycation end-products (AGEs). High soluble receptor for AGE (sRAGE) and low estimated glomerular filtration rate (eGFR) levels are associated with CKD and aging. We evaluated whether eGFR calculated from creatinine and cystatin C share pleiotropic genetic factors with sRAGE. We employed whole-genome sequencing and correlated meta-analyses on combined genome-wide association study (GWAS) p-values in 4182 individuals (age range: 24-110) from the Long Life Family Study (LLFS). We also conducted transcriptome-wide association studies (TWAS) on whole blood in a subset of 1209 individuals. We identified 59 pleiotropic GWAS loci (p < 5 × 10-8) and 17 TWAS genes (Bonferroni-p < 2.73 × 10-6) for eGFR traits and sRAGE. TWAS genes, LSP1 and MIR23AHG, were associated with eGFR and sRAGE located within GWAS loci, lncRNA-KCNQ1OT1 and CACNA1A/CCDC130, respectively. GWAS variants were eQTLs in the kidney glomeruli and tubules, and GWAS genes predicted kidney carcinoma. TWAS genes harbored eQTLs in the kidney, predicted kidney carcinoma, and connected enhancer-promoter variants with kidney function-related phenotypes at p < 5 × 10-8. Additionally, higher allele frequencies of protective variants for eGFR traits were detected in LLFS than in ALFA-Europeans and TOPMed, suggesting better kidney function in healthy-aging LLFS than in general populations. Integrating genomic annotation and transcriptional gene activity revealed the enrichment of genetic elements in kidney function and aging-related processes. The identified pleiotropic loci and gene expressions for eGFR and sRAGE suggest their underlying shared genetic effects and highlight their roles in kidney- and aging-related signaling pathways.

A general quadratic enrichment of the Crouzeix–Raviart finite element

The Crouzeix–Raviart finite element method is widely recognized in the field of finite element analysis due to its nonconforming nature. The main goal of this paper is to present a general strategy for enhancing the Crouzeix–Raviart finite element using quadratic polynomial functions and three additional general degrees of freedom. To achieve this, we present a characterization result on the enriched degrees of freedom, enabling to define a new enriched finite element. This general approach is employed to introduce two distinct admissible families of enriched degrees of freedom. Numerical results demonstrate an enhancement in the accuracy of the proposed method when compared to the standard Crouzeix–Raviart finite element, confirming the effectiveness of the proposed enrichment strategy.

Microbial contribution to the formation of the Carboniferous sedimentary manganese deposits in northwestern China

There is an increasing consensus that microbes play a critical role in the genesis of sedimentary manganese (Mn) carbonate deposits. However, compelling evidence for the microbial involvement during sedimentary Mn metallogenesis remains insufficient, and the specific effects of microbial mediation need to be further elucidated. To advance our understanding of the microbial Mn metallogenesis, multi-scale petrographic observations and high-resolution mineralogical analyses (mainly based on Fourier transform infrared spectrometer and Raman spectroscopy) were conducted on the Carboniferous black shale-hosted Malkansu and limestone-hosted Zhaosu Mn ore deposits in northwestern China. Results show that the Mn ore samples are characterized by finely laminated texture with μm-scale cyclic variations of microbe-associated minerals including rhodochrosite, apatite, quartz, and organic matter as well. These features indicate the ubiquity of microbial mats during Mn mineralization. Microbial involvement is also supported by Mn carbonate aggregates with variable morphologies (filamentous with pearl necklace-like inner forms resembling vermiform morphologies and spheroidal, coccoid-like forms), as well as the annular organic matter that resembles bacterial cells. The cyclic occurrence of trace amounts of remnant Mn oxides verify that primary Mn accumulation took place under oxic bottom waters. The negative co-variation between Mn carbonates and organic matter on Raman profiles suggests that the former was formed during diagenesis via organic matter decomposition coupled with Mn oxide reduction. Combined with previous experimental simulations and natural observations, a two-step microbially mediated Mn metallogenic model is tentatively proposed for the studied Mn deposits: (1) Mn(II)-oxidizing bacteria effectively catalyzed the deposition of considerable Mn oxides under oxygenated bottom water columns, a process that was simultaneously sustained by oxygenic microbial mats such as cyanobacteria; (2) Buried Mn oxides were reduced by highly reactive organic matter sourced from dead biomats of Mn(II)-oxidizing bacteria and benthic phototrophs, a process mediated by Mn(IV)-reducing bacteria which not only promoted the reaction rate but also served as nucleation sites for Mn carbonate minerals. This model can also help to explain the occurrence of diverse authigenic accessory minerals (e.g., quartz, apatite, and talc) and remarkable enrichments of several specific elements (e.g., Co, Ce, and Mo) in the studied Mn ores, which were closely linked to the decomposed cells and extracellular polymeric substance (EPS). By comparing with previous microbial investigations on Mn deposits over geological history, we further highlight the fundamental role of microorganisms in regulating the formation of economic Mn carbonate deposits.