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[Display omitted] • Fe content is likely the dominant factor controlling sphalerite color. • Besides sphalerite, jamesonite is another important Cd-bearing sulfide in the Jianzhupo deposit. • Cd enters the jamesonite lattice by coupled substitution: 2Fe2+ ↔ Zn2+ + Cd2+. • Deposit genesis can be inferred from the Zn/Cd ratio in jamesonite. The Jianzhupo deposit, the largest Zn-Sb deposit in the Wuxu orefield in China, contains abundant sphalerite and jamesonite, contrasting with typical Sb deposits elsewhere. Whether the Sb and Zn in the deposit derived from similar parental sources is not clearly resolved. Here, trace-element compositions of sulfides from the deposit were determined by laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS). Results indicate that jamesonite is an important Cd-bearing sulfide with Cd contents of 523–764 ppm and minor or no significant Cd variations were observed within jamesonite crystals. Trace-element compositions of jamesonite indicates that Cd enters the lattice by coupled substitution as 2Fe2+ ↔ Zn2+ + Cd2+. Due to similar geochemical behaviors between Zn and Cd in hydrothermal systems, Zn/Cd ratio of sphalerite was suggested as a robust geochemical tracer to distinguish metal sources in such systems. Here, we summarized the Zn/Cd ratios of sphalerite from various hydrothermal systems and the results show that values between 169 and 233, and lower than 44 are from high- and low-temperature temperature fluid conditions, respectively. Due to different Zn/Cd ratios between sediments and igneous rocks, we conclude that metals in sphalerite from the Jianzhupo deposit were likely derived from granite; in contrast, metals in jamesonite were related to sedimentary rocks. These conclusions are consistent with previous studies on the deposit. Overall, our results indicate that ore-forming fluids of the Jianzhupo deposit were derived from magmatic–hydrothermal and basin water. This study extends the application of trace-element compositions in resolving the sources of sulfides in hydrothermal systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • There is an abrupt change in the provenance of the base of the Upper Permian Heshan Formation. • The Nb-rich bauxite layer was sourced from the Emeishan LIP and the Permian magmatic arc. • The Li-rich claystone layer was sourced from the Permian Palaeo-Tethyan magmatic arc. The base of the Upper Permian Heshan Formation in Pingguo County, Guangxi Province, SW China, can be divided into two layers: a lower Nb-rich bauxite layer and an upper Li-rich claystone layer. The sources of these layers may have played a critical role in their formation. Detrital zircon provenance analysis is an effective method for identifying sediment provenance; however, it has not been applied previously to the Nb-rich bauxite and Li-rich claystone, thus limiting our knowledge of the sources of these two layers. Detrital zircons from the bauxite and the claystone layers yield a single age peak at ∼ 260 Ma, which is consistent with the age of the Emeishan Large Igneous Province (LIP; 263–257 Ma) and the Permian Palaeo-Tethyan magmatic arcs (300–260 Ma). In contrast, detrital zircons from the two layers yield different trace element signatures. Yttrium and Hf contents and U/Yb ratios of detrital zircon grains from the bauxite layer overlap with those of continental and oceanic crust and have similar Hf/Th, Th/Nb, Th/U, and Nb/Hf ratios to those of zircons of within-plate and magmatic arc origins. These results indicate that the bauxite was sourced from volcanic rocks or ash related to the Emeishan LIP and the Permian Palaeo-Tethyan magmatic arcs. However, detrital zircons from the claystone have similar Hf/Th, Th/Nb, Th/U, and Nb/Hf ratios to only those of zircon from magmatic arcs, suggesting a single Permian Palaeo-Tethyan magmatic arc source. Thus, our results reveal an abrupt change in the provenance of zircons at the base of the Heshan Formation. The lower Nb-rich bauxite layer was derived from the weathering of volcanic rocks or ash related to the Emeishan LIP and the Permian Palaeo-Tethyan magmatic arcs, whereas the upper Li-rich claystone layer was derived principally from the weathering of volcanic ash related to the Permian Palaeo-Tethyan magmatic arcs. Since Nb is an immobile element, volcanic rocks/ash related to the Emeishan LIP and the Permian magmatic arc could represent a source for bauxite and Nb. In contrast, Li is chemically highly mobile in the Earth's surface environment and its origin cannot be constrained easily, further work is needed to identify the sources of Li. [ABSTRACT FROM AUTHOR]

Similar to marine oxygen level and nutrient supply, seawater salinity has also been suggested as an important control on marine biological evolution. However, the potential links between the seawater salinity and Cambrian Explosion remain unclear. Here, we conducted high-resolution analyses of B/Ga and B/K ratios on four typical sections from different water-depth environments to constrain the paleosalinity in the Nanhua Basin (South China) from late Age 2 to Age 3 (~526–515 Ma). Our new data revealed common hypersaline conditions at shallow-water Meishucun (B/Ga = 13.8 ± 2.3 and B/K = 73.5 ± 15.7) and Wangjiaping (B/Ga = 20.6 ± 2.7 and B/K = 101.1 ± 17.1) locales during most of the period from late Age 2 to Age 3. In contrast, combined with the deep-water data in a recent study, middle- to deep-water environments were dominated by brackish to normal seawater salinity, as documented at Zhijin (B/Ga = 8.0 ± 1.1 and B/K = 48.2 ± 4.5), Daotuo (B/Ga = 6.4 ± 1.6 and B/K = 57.6 ± 12.3), Yuanjia (B/Ga = 4.3 ± 2.7), and Zhalagou (B/Ga = 6.1 ± 1.2) locales. Notably, two transient low-salinity intervals (LS1 and LS2) developed in shallow-water regions at ~526 Ma and ~ 518 Ma, respectively, because of increased freshwater inputs, during which the watermass salinity may be inhabitable for early faunas. Combined with previous redox studies, however, transient shallow-water anoxia at ~525 Ma allowed only the development of hypoxia-tolerant sponge faunas during LS1, indicating redox constrains on the early biological evolution. Additionally, although studies indicated rapid oceanic oxygenation within the hypersaline interval between LS1 and LS2, no important biotas occurred at this hypersaline interval, indicating hypersalinity restriction on metazoan diversification. Instead, when normal seawater salinity and oxic watermass were jointly formed during LS2 (~518 Ma), the Chengjiang and Qingjiang biotas experienced notable explosion. Therefore, the influences of the seawater salinity on early life evolution should be given more attention in the future. • Paleosalinity reconstruction of the early Cambrian Nanhua Basin. • Hypersaline conditions are common in the Nanhua Basin shallow waters. • Two relatively low salinity intervals occurred at ~526 Ma and ~ 518 Ma. • Paleosalinity may have critically controlled the Cambrian Explosion. [ABSTRACT FROM AUTHOR]

The recovery of lithium (Li) from coal ash has gained growing attention as a promising Li resource. Compared with extensive studies on the modes of occurrence of Li in coal and coal ash, few studies have investigated the migration and mineral host changes of Li during coal combustion. This study investigates the modes of occurrence of Li in feed coal, the conversion of minerals, the Li-host changes, and the influencing factors during coal combustion. The results show that Li is enriched in the feed coal, possibly mainly in the octahedral sites of kaolinite and illite/smectite (I/S). Kaolinite and I/S are dehydrated and dehydroxylated at high temperatures to form aluminosilicate glass, which then partially transforms into pseudomullite at 826 °C and further converts to mullite at 1282 °C. Temperature is the main factor controlling the Li-host changes during coal combustion. The proportion of easily leachable Li decreases with increasing in temperature (400–1000 °C), and the leachability of Li is optimal at 500 °C regarding possible extraction prospects. Oxy-fuel combustion reduces the temperature of coal particles, resulting in a relatively higher proportion of easily leachable Li from oxy-fuel combustion compared with air combustion at 700 °C. The Li-host phase changes are discussed in detail using sequential chemical extraction assisted with thermodynamic calculation (HSC Chemistry 10). The Li related to kaolinite and I/S in coal mainly migrates into the octahedral positions of clay minerals to form lithium aluminosilicate. Portions of the Li react with Fe, Mn, and S to form lithium manganese/iron oxides and lithium sulfate. This study evaluates the extraction potential of Li from coal by experimental heating under different atmospheres and the study of mineralogical changes of Li-hosts, providing practical guidance for the recovery of Li from coal. • Li is enriched in the feed coal, which is related to kaolinite and illite/smectite (I/S). • Temperature is the main factor controlling the occurrence transformation of Li. • The most effective extraction of Li occurs when the coal is heated to 500 °C in air. • The easily leachable Li in oxy-fuel combustion is higher than in air combustion. • The Li-hosts were determined by thermodynamic energy minimization. [ABSTRACT FROM AUTHOR]

[Display omitted] • REY composition of Neoproterozoic seawater was similar to modern seawater. • Terrigenous REY contributions are significant in phosphorite during the early Ediacaran period. • REY enrichment in apatites was mainly resulted from mixed REY sources. During the Ediacaran period, massive marine phosphorites were deposited worldwide, which could represent a global sink of rare earth elements and yttrium (REY) in oceans. In the Doushantuo Formation of South China, the REY source has been preliminarily constrained as the mixed sources of seawater and terrigenous matter in these phosphorites. However, the REY composition of both seawater and terrigenous endmembers is still unclear; therefore, it's difficult to identify the contributions of seawater and terrigenous sourced REY. In this work, REY and other trace elements of bulk phosphorites, in situ carbonates, and apatite grains were analyzed from a drill core (Fangmashan) of the Doushantuo Formation in South China. Combined with mineralogical observations, the REY composition of seawater and terrigenous endmembers is well-constrained. Along the investigated Fangmashan drill core, all in situ carbonates (calcites and dolomites) show a modern seawater-like REY pattern, indicating that the REY characteristics of the Doushantuo seawater could be similar to those of modern oxic seawater without significant changes. Alternatively, apatites from the lower and upper phosphorites showed distinct REY patterns. One type of apatite in the upper phosphorites showed a modern seawater-like REY pattern, indicating authigenic REE enrichment from the seawater column. However, another type of apatite in the upper phosphorites with an REE pattern that deviated from seawater showed high ΣREY (∼691.16 ± 309.78) and low Y/Ho (∼40.52 ± 4.05), probably reflecting mixed REY sources and/or the effects of early diagenesis. It is noted that most apatites in the lower phosphorites are obviously enriched in light REY (LREY: La - Nd) compared to heavy REY (HREY: Ho - Lu and Y), which may represent a significant contribution of the terrestrial REY source. This study reveals that the REY composition of paleo-seawater could be similar to modern seawater as early as the Neoproterozoic and supports a significant contribution to understanding the difference in the REY composition of phosphorites in geological history. [ABSTRACT FROM AUTHOR]

• δ 114/110Cd values were determined for sulfides of the Zhugongtang Zn–Pb deposit, China. • Metals of the deposit were derived from a mixture of basement and sedimentary rocks. • Metal concentrations in deposits of the SYGMP were likely controlled by source rocks. The Sichuan–Yunnan–Guizhou metallogenic province (SYGMP) includes > 400 Zn − Pb deposits and prospects, eight of which are large-scale deposits with large reserves of critical metals such as Cd and Ge, including the Huize Zn − Pb − Cd − Ge and Daliangzi Zn–Pb–Ge–Cd deposits. The newly discovered Zhugongtang Zn − Pb deposit is a super-large deposit with Zn–Pb reserves of > 3 Mt. Its geochemical features are similar to those of the Huize deposit, with similar sulfide δ34S values and concentrations of critical elements in sphalerite (e.g., Cd and Ge). However, the two deposits have different host strata, and it remains unclear as to whether they have similar oregenesis. In this study, δ 114/110Cd values and major- and trace-element compositions of sphalerites collected from a drill-core and tunnels of the Zhugongtang deposit were determined in an investigation of metal sources. Drill-core samples were impure and exhibited strong correlation (R2 = 0.89) between Zn and Cd contents. For samples from mining tunnels, the Cd and Fe contents of selected sphalerites were positively correlated, especially yellow sphalerites (R2 = 0.76). Cadmium is likely hosted in sphalerite by the substitution mechanism of (Fe2+, Cd2+) ↔ Zn2+. The δ 114/110Cd values of all samples ranged from − 0.43 ‰ to 0.06 ‰. Based on Zn/Cd ratios, and excluding geochemical processes that may have caused the variable Cd isotopic compositions, we suggest that the metal sources of the deposit were derived from the mixing of sedimentary and basement rocks. This model is supported by the strong relationship between the δ 114/110Cd and 1/Cd values of sphalerites from 11 typical Zn–Pb deposits in the SYGMP (R2 = 0.81). The quantification of metal contributions of source rocks indicates that deposits derived mainly from sedimentary rocks generally have relatively low sphalerite Ge contents and small Ge reserves, whereas those derived mainly from basement rocks have higher Ge contents and larger Ge reserves. This study provides a new model for explaining the enrichment of critical metals in Zn–Pb deposits of the SYGMP, thus extending the applications of Cd isotopes in hydrothermal systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • Black shale of the upper Carboniferous Maping Formation is rich in Li (∼1000 ppm). • Li-rich illite is the likely carrier of Li. • The Li-rich shale was formed under anoxic depositional conditions. Lithium is used in rechargeable batteries due to its high electrochemical potential, and the rapid development of electric vehicles is exerting increasing pressure on reserves. Currently, pegmatites and brine deposits are the two main Li sources, although volcanic clay-type and carbonate-hosted clay-type that formed mainly in continental or coastal basins are receiving increasing attention due to their large size and potential as future Li sources. However, mechanisms of clay Li enrichment are still debated. Marine black shale at the top of the upper Carboniferous-lower Permian Maping Formation in the Nandan area, northern Guangxi, SW China, is enriched in Li to levels of ∼1000 ppm. Knowledge of its genetic mechanism would contribute to understanding the geochemical behaviour and enrichment mechanisms of Li in surface environments. The different geological features of the shale, relative to the above clay types, suggest that the Nandan shale is a new type of Li-rich sedimentary rock. Its whole-rock Li contents are positively correlated with K 2 O and illite contents, indicating that illite (K 0.7 Al 2 [(Si,Al) 4 O 10 ](OH) 2) is the carrier of Li in the shale, as supported by high shale Al, Si, K, and Li contents in the in situ images. Mineralogical studies have revealed that the Li-rich illite is of detrital origin and was formed during continental weathering. The widespread occurrence of framboidal pyrite and high contents of TOC in the shale indicate that Li-rich shales formed under anoxic depositional conditions. Our findings may provide reference material for the study of the genesis of clay-type Li resources. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Y/Ho ratios and Sr–Nd isotopes of Zhijin phosphorites were reported. • REY in Zhijin paleo-seawater was derived from weathering granite. • Relationship between granite weathering and marine REY deposition was proposed. The early Cambrian Zhijin phosphorite in Guizhou province, China, has high rare earth elements and yttrium (REY) contents of up to 2500 ppm, with heavy REY (HREY) accounting for ∼30 % of the total REY. However, their REY sources are not well-determined. Herein, elemental geochemistry and Sr–Nd isotopes of phosphorites in four sections from the Zhijin phosphorite ore area were investigated, primarily to constrain the contributions of seawater and terrestrial REY sources to the REY enrichment in these phosphorites. Zhijin phosphorites have high Y/Ho (45–63) and seawater signature's 87Sr/86Sr(i) ratios (0.7085–0.7092), suggesting a partial contribution from seawater-sourced REY. On the other hand, Zhijin phosphorites have ε Nd (t) values of −8.6 – −6.8, indicative of the great influence from continental weathering. The Y/Ho ratios exhibit negative correlations with their Zr contents and Sm N /Yb N ratios; meanwhile the 87Sr/86Sr(i) ratios exhibit positive correlations with their Sr contents and REY contents, indicating that terrestrial source contributions played an important role in REY enrichment in Zhijin phosphorites. Furthermore, the provenance of Zhijin shales indicates the terrigenous granite weathering, during which the regolith-hosted REY could be transported to Zhijin shallow seawater, providing abundant REY to Zhijin phosphorites. We proposed that the REY enrichment in Zhijin phosphorites could be associated with high REY seawater induced by granite weathering. This study provides a new perspective on the relationship between granite weathering and marine REY deposition, which may be a common phenomenon in geological history but remains to be fully investigated in future. [ABSTRACT FROM AUTHOR]

The chemical evolution of the ocean is one major component of the puzzle of how climate and life have co-evolved over the Earth's history. A "soda ocean" with high alkalinity, high pH, and low calcium concentration in Precambrian has been proposed to explain the emergence and evolution of early life. However, this hypothesis has not been widely accepted due to the lack of reliable tracers for the chemical composition of Precambrian seawater. Evaporite is formed during seawater/brine evaporation and thus has been widely used to reconstruct the ancient seawater/brine chemical composition. Here, evaporation experiments were conducted using Qinghai Lake (QHL) water, a modern soda lake, to provide an analogy of the Precambrian "soda ocean" evaporation and investigate the mineralogical and Mg isotopic signatures of alkaline brine-derived evaporites. Our results show that the evaporation path of QHL water overall covers the stages of hydrous Mg carbonates (hydromagnesite), halite, and bloedite [Na 2 Mg(SO 4) 2 ·4H 2 O] precipitation. The precipitation of hydrous Mg carbonates and bloedite is distinct from the modern seawater evaporation and is accompanied by the removal of up to 85% Mg from brine. The brine gradually becomes enriched in heavy Mg isotopes during evaporation due to the preferential incorporation of light Mg isotopes into precipitates. The fractionation of Mg isotopes is dominantly controlled by the bond structure during hydrous Mg carbonates and bloedite precipitation, and the latter is also slightly influenced by the kinetics in the highly concentrated brine. The Mg isotope fractionation during bloedite dissolution is limited due to the rapid congruent dissolution. The significant Mg isotopic fractionation observed within the hydrous Mg carbonates precipitation during the earliest QHL water evaporation indicates the potential Rayleigh distillation of Mg by alkalinity in the "soda ocean", which is absent in the Phanerozoic oceans. Therefore, the large Mg isotope fractionation during alkaline brine evaporation can be applied to test the existence of Precambrian "soda oceans". [ABSTRACT FROM AUTHOR]

Organic-rich shales exhibit a wide range of vanadium (V) concentrations in deep-time successions. Although V accumulation is generally acknowledged to be related to redox state, organic matter and clay mineral content, previous studies have failed to explain the mechanism of variable V enrichment in organic-rich shales. Here, we hypothesize that clay-organic nanocomposites control authigenic V uptake in organic-rich shales. Specifically, V is scavenged by dissolved organic matter in seawater, which is then taken up by smectite during transport or deposition, followed by V incorporation into illite through illitization of smectite and pyrolysis of organic matter during diagenesis. To test this hypothesis, lower Cambrian black shales from South China were investigated by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) at a micro- and nanoscale. Results show that only 1M/1M d -type illite, generated through transformation from a smectite precursor, has significant V concentrations (0.7–4.8 wt%), whereas 2M 1 -type illite and other minerals contain little or no V. All 1M/1M d -type illite was closely associated with organic matter, occurring as clay-organic nanocomposites. Our results are significant in (i) showing clay-organic nanocomposites play a key role in V cycling in the marine system, (ii) providing a mechanism for understanding variations in the V concentrations of deep-time organic-rich shales, and (iii) improving strategies for prospecting and extraction of V ores. [ABSTRACT FROM AUTHOR]

Heavy metals pollutants are global concern due to their toxicities and persistence in the environment. Cd isotope signatures in soils and sediments change during weathering, and it remains unclear if Cd isotopes can effectively trace Cd sources in a riverine system. In this study, we investigate Cd concentration and its isotope compositions, as well as other heavy metals of sediments and related potential Cd sources in a riverine system. The results showed that the two river sediments evaluated were moderately polluted by Zn, Cr, and Cd, while the source samples (soil, sludge, waste, and raw materials) were seriously polluted by heavy metals derived from anthropogenic activities. According to comprehensive ecological risks, the two sediments have a moderate to low potential risk and more than half of all anthropogenic activities in the study area were at considerable or moderate potential risk. We determined that Cd pollution in river sediments was primarily derived from sewage treatment and outlets based on river flow direction and the isotope geochemical behaviors of the Cd isotope in nature conditions. This study further confirmed that analyzing Cd isotopes could be a powerful tool for tracing the source and destination of environmental Cd for multiple sources with similar Cd concentrations. Unlabelled Image • The dominant Cd pollution was distinguished from multiple sources with similar Cd concentrations based on Cd isotopes. • Cd pollution in river sediments was primarily derived from sewage treatment and outlets. • The Cd isotope technique is effective to trace Cd sources in riverine systems. [ABSTRACT FROM AUTHOR]

• Determined Ge isotopic compositions in sphalerite in the Fule deposit. • Performance of δ 74/70Ge and Ge contents in sphalerite decline linearly in sphalerite. • Ge contents of sphalerite may be controlled by the temperature of the ore-forming fluid. • Performance of δ 114/110Cd and δ 74/70Ge decline linearly during sphalerite precipitation. • Rayleigh process control Ge and Cd isotope variations in sphalerite. The Sichuan–Yunnan–Guizhou metallogenic province in southwest China is one of the most important low-temperature metallogenic domains in the country, and more than 400 Pb–Zn deposits and/or mineralization points are located in this area. The Fule deposit is better known that the other Pb–Zn deposits in the region because it is extremely highly enriched with dispersed elements, including Ge, Ga, and Cd. Based on information obtained from our previous studies, the contents of Ge and its isotopic compositions in sphalerite are investigated herein. Results show that the Ge content ranges from 60 ppm to 141.5 ppm, and δ 74/70Ge values vary from −6.57‰ to 0.97‰. In this respect, −6.57‰ is the most negative Ge isotope composition value reported in any sphalerite or seafloor sulfides to date. The Cd and Ge contents in sphalerite have a good negative relationship, and it is suggested that the mechanisms of Cd and Zn substitution are responsible for the low incorporation of Ge and relate to the high Cd content (up to 3%) of the sphalerite. In addition, there is a good positive correlation between the Ge contents and δ34S values, which was likely triggered by variations of fluid temperature. In the same hand specimen, light Ge isotope is more likely to be enriched in dark sphalerite rather than light sphalerite, similarly to Cd isotope distribution in dark and light-colored sphalerite. In addition, Cd and Ge isotope compositions, measured in an ore profile from SBFL22 to SBFL26, show a good positive relationship, suggesting that the fractionation mechanisms between Cd and Ge isotopes may be similar and they were controlled by kinetic fractionation during sphalerite precipitation. Based upon previous limited studies, we conclude that Ge in the Fule deposit is derived from mixing sources and sediment is likely the dominant one. [ABSTRACT FROM AUTHOR]

• Determined Zn isotopic compositions in sphalerite. • We firstly reported a logarithmic regression between δ66Zn values and Cd/Zn ratios of sphalerite from Zn-Pb deposits. • Fluid mixing controls the overall Zn isotope variations in sphalerite. • Zn isotopes, coupled with Cd/Zn ratios, could be used as a tool to track metal sources. The Sichuan–Yunnan–Guizhou (SYG) area is a world-class Zn-Pb metallogenic zone and contains over four hundred of carbonate-hosted hydrothermal Zn-Pb deposits, six of which are super large-scale deposits with significant sources of Cd, Ge, and Ag, including the Huize, Wusihe, Xiaoshifang, Maozu, Tianbaoshan and Daliangzi deposits. Although previous studies focused fully on these deposits, the ore genesis of which are still in controversial. Interestedly, four of those super large scale deposits are hosted in the Ediacaran Dengying Formation, including the Maozu, Wusihe, Tianbaoshan and Daliangzi deposits. Based upon previous studies, we investigate the extent, causes and consequences of Zn and Pb isotope signatures at hand specimen scale and ore genesis of the Daliangzi and Tianbaoshan deposits, associated with published data for the Wusihe deposit. Lead isotope ratios, coupled with published data, demonstrate that Pb in the studied deposits was predominantly derived from two components: basements and sedimentary rocks. Meanwhile, a strong positive linear correlation between δ66Zn and δ34S CDT values was observed in hand specimen D-2084, suggesting the variations may be resulted by fluid mixing. Furthuremore, the Zn isotope and Cd/Zn dataset from the Tianbaoshan, Daliangzi and Wusihe deposits defines a logarithmic curve (R2 = 0.82), which, to our knowledege, is firstly reported and lies between two indentified components: a low Cd/Zn end-member with high δ66Zn values and a high Cd/Zn end-member with low δ66Zn values. Based upon previous studies, we suggest that Zn and Pb in the Wusihe and Tianbaoshan deposits were predominantly derived from basements and Ediacaran sediments; in contrast, Zn and Pb in the Daliangzi deposit were predominantly derived from Ediacaran sediments and upper sedimentary rocks, but we cannot rule out metal contributions of the basements. Furthermore, we suggest that fluid mixing is more propreate to better explain Zn isotope signatures in the studied deposits. In summary, Zn and Pb isotope ratios reflect similar ore genesis and metal sources of the Daliangzi, Tianbaoshan and Wusihe Zn-Pb deposits in the SYG area. The application to the studied deposits with the discovery of Zn, S and Pb isotope compositions for sulfides indicates the potential of Zn isotope, combined with Cd/Zn raito, as new geochemical tracers, which may be useful for distinguishing the metal sources in large hydrothermal systems as suggested previously. [ABSTRACT FROM AUTHOR]

Early Cambrian black shales of the Niutitang Formation are found across the Yangtze Platform in a 1600-km belt extending across south China. A thin organic matter-rich layer in the lowermost part of this formation contains exceptional concentrations in Mo, Ni, Se, Re, Os, As, Hg, Sb, Ag, Au, Pt, Pd, and Ag. Due to their extreme metal enrichment, these black shales provide a rare opportunity to study the interface between semi-metals, metals and biogenic material. We report the first detailed μm-scale investigation of metal distributions and associations in samples from two sites, Zunyi and Sancha, located hundreds of km apart, using a combination of analytical techniques including X-ray fluorescence (XRF) mapping, scanning electron microscopy (SEM), Synchrotron-based XRF mapping, electron probe micro-analyser (EPMA), particle induced x-ray emission (PIXE) probe and x-ray absorption near-edge structures (XANES) imaging. Strong μm-scale variations in metal and semi-metal distributions were highlighted by Synchrotron-based XRF mapping of samples from both sites. At both locations, U is present within phosphorite nodules. Arsenic, Mo and Se are particularly abundant in the organic-rich matrix, showing strong associations with organic matter. Nickel, however, shows different distributions between the two sites. It is mainly present in association with the organic matter at the Sancha site while it is found in abundance in millerite at the Zunyi site, suggesting slightly different local conditions at Zunyi favouring Ni-S associations over Ni-organic matter. At both sites, biogenic structures were re-mineralised with laminations dominated by different metals, indicating a likely control of organic matter over metal distributions. In addition, the XANES imaging highlighted different redox states of As over μm-scale areas. While As−1 appears to be mainly present in pyrite, As+3 was mainly detected in association within the carbon and MoS 2 mixed layer phase (MoSC). Overall, the present results emphasize the complexity of metal associations in this mineralised layer, the significant role of organic matter in the accumulation and precipitation of metals and semi-metals in these metalliferous shales and highlight how biogenic activity can induce μm-scale variations in redox conditions in sediments. • Multi-proxy characterisation of metal distributions at µm-scale from two sites in South China • Presence of remineralised biogenic structures with laminations dominated by different metals and semi-metals • XANES imaging reveals different redox states of As over µm-scale areas • Results reveal the influence of biogenic activity on µm-scale variations in redox conditions in the Niutitang shales [ABSTRACT FROM AUTHOR]

Forensic identification of human remains is crucial for legal, humanitarian, and civil reasons. Wide heterogeneity in sphenoid sinus morphology can be used for personal identification. This study aimed to propose a new protocol for personal identification based on three-dimensional (3D) reconstruction of sphenoid sinus CT images using Iterative Closest Point (ICP) algorithm. Seven hundred thirty-two patients which consisted of 348 females and 384 males were retrospectively included. The study sample includes 732 previous images as a source point set and 743 later ones as a scene target set. The sphenoid sinus computed tomography (CT) images were processed on a workstation (Dolphin imaging) to obtain 3D images and stored as a file format of Stereo lithography (.STL). Then, a Python library vtkplotter was used to transform the STL format to PLY format, which was adapted to Point Cloud Library (PCL). The ICP algorithm was used for point clouds matching. The metric Rank-N recognition rate was used for evaluation. The scene target set of 743 individuals was compared with the source point set of 732 individual models and achieved Rank-1 accuracy of 96.24%, Rank-2 accuracy of 99.73%, and Rank-3 accuracy of 100%. Our results indicated that the 3D point cloud registration of sphenoid sinuses was useful for assessing personal identification in forensic contexts., (© 2022. The Author(s) under exclusive licence to Society for Imaging Informatics in Medicine.)

Human identification plays a significant role in the investigations of disasters and criminal cases. Human identification could be achieved quickly and efficiently via 3D sphenoid sinus models by customized convolutional neural networks. In this retrospective study, a deep learning neural network was proposed to achieve human identification of 1475 noncontrast thin-slice CT scans. A total of 732 patients were retrieved and studied (82% for model training and 18% for testing). By establishing an individual recognition framework, the anonymous sphenoid sinus model was matched and cross-tested, and the performance of the framework also was evaluated on the test set using the recognition rate, ROC curve and identification speed. Finally, manual matching was performed based on the framework results in the test set. Out of a total of 732 subjects (mean age 46.45 years ± 14.92 (SD); 349 women), 600 subjects were trained, and 132 subjects were tested. The present automatic human identification has achieved Rank 1 and Rank 5 accuracy values of 93.94% and 99.24%, respectively, in the test set. In addition, all the identifications were completed within 55 s, which manifested the inference speed of the test set. We used the comparison results of the MVSS-Net to exclude sphenoid sinus models with low similarity and carried out traditional visual comparisons of the CT anatomical aspects of the sphenoid sinus of 132 individuals with an accuracy of 100%. The customized deep learning framework achieves reliable and fast human identification based on a 3D sphenoid sinus and can assist forensic radiologists in human identification accuracy., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)