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Genesis of the oxidized Sn ores in the Gejiu district, Yunnan Province, SW China

Year: 2020
Products: UP193-FX;
Authors: Zhang, Y;Zhou, J;Tan, S;Li, H;Hao, S;Jiang, Y;He, X;
Journal: Ore Geology Reviews

The Gejiu Sn ore district, one of the largest Sn producing area (300Mt @1 wt% Sn) in the world, is located in the western margin of the Cathaysia Block, SW China. There are five types of Sn ores in the Gejiu district, including greisen, skarn, veined tourmaline, massive sulfide and oxidized. Among these types of Sn ores, the genesis of the oxidized Sn ores is most controversial, such as magmatic hydrothermal origin and sedimentary exhalative (SEDEX) or hot water deposition (Red Sea type). This paper reports U-Pb ages, fluid inclusions, trace elements and H-O isotopes of cassiterite from the oxidized Sn ores, aiming to solve this issue. LA-MC-ICPMS cassiterite U-Pb dating yielded an age of 86.7 ± 2.8 Ma, which is accordant with the formation ages (~86 Ma) of granitic intrusions in the Gejiu district. Two types of fluid inclusions in cassiterite from the oxidized Sn ores were observed, one type is CO2-rich inclusions (Type 1) and the other type is aqueous inclusions (Type 2). The homogenization temperatures range from 220 to 366 °C and the salinities range from 10.9 to 21 wt% NaCl equiv. for the two types of fluid inclusions. Furthermore, fluid inclusions in cassiterite from the oxidized Sn ores located at 300 m far away from granitic intrusions have higher temperatures (357–366 °C) than those located at 500 m (273–330 °C). Hence, the ore-forming temperatures tend to decrease with the distance far away from the magmatic hydrothermal center. The vapor components for the two types of fluid inclusions are CO2 and H2O, respectively, and the liquid phase compositions of them are all H2O. The CO2 in the ore-forming fluids may source from marble by decarbonization. This indicates that the precipitation of cassiterite is resulted from fluid immiscible. The δ18O values of fluid inclusions in cassiterite range from +6.1 to +7.7‰, and the δD values range from −135 to −153‰, indicating a mixture of magmatic and meteoric waters. Trace elements show that cassiterite is rich in In, Rb and U, but Ba, Nb and Ti are depleted. In addition, the lower Sr (0.4–2.1 ppm) and higher Sc (35.9–53.7 ppm) contents reflect that the formation of cassiterite is related to F-rich intermediate-acid magma. Cassiterite has a relatively low total REE contents (2.7–9.2 ppm) with negative Eu (δEu = 0.14–0.76) and Ce (δCe = 0.1–0.6) anomalies, indicating that the ore-forming environment is oxidized. This is consistent with the cassiterite precipitation conditions. Hence, all the evidence supports that the oxidized Sn ores are genetically associated with the Gejiu granitic magmatism.

Origin of Paleozoic granitoids in the Yuhai Cu–Mo deposit, Eastern Tianshan, NW China and implications for regional metallogeny

Year: 2020
Products: NWR193;ESI;
Authors: Zhang, W;Zhang, F;Wang, Y;Xue, C;Wang, J;Sun, M;Wang, K;
Journal: Ore Geology Reviews

The Yuhai porphyry Cu–Mo deposit is located at the eastern section of the Dananhu–Tousuquan Arc in Eastern Tianshan, NW China. Cu–Mo mineralization generally occurs as disseminations and veins in potassic and phyllic alteration zones, and is predominantly hosted in the Yuhai quartz diorite, granodiorite and minor syenogranite intrusions. New LA–ICP–MS zircon U–Pb dating indicates that the acidic syenogranite was emplaced at 318–320 Ma, younger than the intermediate rocks (i.e., quartz diorite and granodiorite) with Silurian ages. The acidic to intermediate intrusions exhibit geochemical affinities with normal arc rocks (e.g. high Y and Yb contents, and low Sr/Y ratios), in contrast with the subducted slab-derived adakites hosting large porphyry Cu deposits (e.g. Tuwu–Yandong) in the middle section of the Dananhu–Tousuquan Arc. The Yuhai acidic syenogranite rocks have high SiO2 (≥74.90 wt%), and K2O (≥3.48 wt%), relatively low Mg# and compatible element contents (e.g. Cr = 0.65–3.37 ppm; Ni = 0.63–1.02 ppm), and strong depletions in HFSE (e.g. Nb, Ta, and Ti). These geochemical features, coupled with isotopic data such as low initial 87Sr/86Sr (≤0.7033), positive εNd(t) (4.0 to 5.9) and εHf(t) (≥11) values, young Hf model ages, and variable 206Pb/204Pb ratios (18.549 to 19.465) reported in this study, suggest that their parental magmas originated from the partial melting of a juvenile lower crust and mixed with some old crustal components beneath the Dananhu–Tousuquan Arc. In contrast, the Yuhai intermediate intrusions exhibit relatively low SiO2 and K2O contents, high Mg# values (40–56), and a wide range of εHf(t) values, suggesting a source of sub-continental lithospheric mantle metasomatized by slab-derived fluids and melts. Zircon trace element and plagioclase compositions of the Yuhai granitoids further imply that the Silurian intermediate intrusion-related magma was moderately oxidized (mostly EuN/EuN* > 0.6) and water-rich (~9 wt%), favorable for the copper mineralization, whereas the Carboniferous syenogranite-related magma was weakly oxidized (mostly EuN/EuN* = 0.3–0.6) but also hydrous (~6 wt%). Combined with the regional tectono-magmatic activities and metallogenic processes, we suggest that the Yuhai Cu–Mo deposit and associated granitoids were formed in an arc setting, and that the magma nature and its source components are the key factors constraining the distribution, scale and style of the porphyry copper mineralization in Eastern Tianshan.

Manganese ores in Tunisia: Genetic constraints from trace element geochemistry and mineralogy

Year: 2020
Products: UP213;New Wave;New Wave Research;
Authors: Garnit, H;Kraemer, D;Bouhlel, S;Davoli, M;Barca, D;
Journal: Ore Geology Reviews

Northern and central Tunisia hosts few small-scale stratiform and stratabound Mn deposits, low to medium in grade (Mn < 46%), which have a spatial distribution related to major reactivated NS- and NW-oriented faults. The Mn deposits can be broadly classified into sedimentary rock-hosted and karst-hosted. The ores occur in two different structural settings and are hosted by deposits of various age, lithology, size and grade. The geology shows that the Mn deposits are diachronic and were formed in continental and/or shallow marine environments. They commonly occur in close spatial association with Fe ores and are genetically not related to Pb-Zn-(Ba-Sr-F) deposits. Bulk Mn ores are characterized by high and variable Mn/Fe ratios and an enrichment in Pb, Zn, Ba and Sr. Shale-normalized trace element (TESN) patterns of all studied Mn ores show enrichment in the assemblage of Sr, Ba, Co, Cu, Mo, Pb, and Zn and depletion in high-field strength elements Zr, Nb and Th, which is characteristic for hydrothermal ore formation. Total rare earth element (REE) contents show considerable variations and REYSN patterns indicate a complex interplay of hydrothermal, marine and meteoric/supergene processes. LA-ICP-MS analysis of Mn oxides show considerable variations in TE contents and REYSN patterns due to differences in oxide mineralogy, fluid source(s), and their rate of precipitation and related scavenging processes. The TE and REY geochemistry of the Mn ores indicate a complex interplay of primary and secondary processes that were responsible for the formation of the Mn mineralization. In the Tamra Fe-Mn deposit (Nappes zone, polymetallic district and volcanosedimentary context), the Mn ores (stage 1 romanechite-hollandite) occur as porosity and/or microfracture fillings in the ferruginous matrix, as impregnation and massive concretions and also as late cavity fillings (stage 2 coronadite-chalcophanite). Mixing of hydrothermal and predominantly meteoric fluids induced the formation of typical supergene Mn ores. The stratiform Mn ores (pyrolusite) of Jebel Es Stah (southern Tunisian Atlas, Miocene alluvial system) occur as a syngenetic to early diagenetic oxide coating and cementation of detrital sand grains. REYSN patterns reflect the predominant influence of siliciclastic material as detritus in the Mn ore. Minor Mn ores (cryptomelane, hollandite) occurring as duricrust and fracture filling recorded in the Cenomanian-Turonian dolostone in central and southern Tunisian Atlas show flat REYSN patterns and negative CeSN anomalies and suggest remobilization of Mn under supergene conditions. In the Jebel Ank Fe-Mn deposit (southern Tunisian Atlas, hosted in a relatively restricted shallow basin), cryptomelane occurs as centimeter-sized irregular nodules in the late Eocene marls. Based on REY data, a primary hydrogenetic origin is suggested for Mn nodules. The formation of cryptomelane may have occurred at relatively late stages of weathering when local increases in pH and oxidizing conditions prevailed with the input of K+ from phyllosilicate-bearing layers. The stratabound Mn ores (stage 1 hollandite and stage 2 romanechite-coronadite) in the Jebel Aziza Mn deposit (southern Tunisian Atlas, shallow marine platform facies) correspond to karstic filling and stockwork type in the late Cenomanian-early Turonian dolostone. The Mn oxides in the deposit are epigenetic and their formation is related to changes in Eh and pH. The REYSN patterns for Mn ores and Mn oxides are between those of a mixed seawater-hydrothermal- and supergene-type Mn ore. The petrography, mineralogy, TE contents and REYSN patterns of the different Mn ores indicate interplay of hydrothermal, hydrogenetic and supergene weathering processes occurring during formation of the deposits. The data indicates different mineralization stages and different processes that lead to the low-temperature formation of Mn oxides typical of supergene deposits commonly found in North Africa.

Analysis of the Infiltrative Metasomatic Relationships Controlling Skarn Mineralization at the Abbas-Abad Fe-Cu Deposit, Isfahan, North Zefreh Fault, Central Iran

Year: 2020
Products: NWR213;Electro Scientific Industries;
Authors: Alaminia, Z;Tadayon, M;Finger, F;Lentz, D;Waitzinger, M;
Journal: Ore Geology Reviews

The Abbas-Abad volcano-sedimentary-hosted Fe-Cu skarn deposit, NE Isfahan, is one of the most important skarns in the central Urumieh-Dokhtar magmatic arc. It was formed along the contact with the Dorojin granitoid massif next to the Zefreh Fault. The plutonic rocks are of I-type, volcanic arc affinity with normal-K, metaluminous, calc-alkaline to calcic quartz diorite, tonalite, and granodiorite, similar to many other Fe-type skarn-related granitoids worldwide. The parent magma involved in this skarn system is high temperature and relatively oxidized. Amphibole geobarometery in quartz diorite yielded a crystallization pressure lower than 200 MPa (2 kb, ~7 km) at 724° to 785 °C. Granitoid compositions around the ore deposit are mainly granodiorite. U-Pb zircon dating yields Early Miocene ages of 23.0 ± 1.6 Ma for a quartz dioritic rock and 21.3 ± 1.5 Ma for a tonalitic sample. The injection and cooling of the granodiorite produced a hornblende hornfels aureole with endoskarn. Paragenetic relationships and microprobe data indicate that Abbas-Abad calcic skarn evolution can be subdivided into three stages as follow: (I) Prograde skarn associated andradite-rich garnet (Adr93-98Grs0-4Spe1-2) and pyroxene, (II) Retrograde skarn starting with garnet (Adr53-69Grs28-43Spe2-4), magnetite, and sulfide minerals associated with calcic-alteration, and (III) Post-ore with pyrite, chalcedony, epidote, quartz, calcite, and zeolite veinlets. Textural and compositional studies of garnet and magnetite from the garnet-bearing exoskarn zone reveal the multiple events associated with skarn formation. Garnets are characterized by low TiO2 and relatively high CaO that are indicative of a calcareous wall-rock among Eocene volcaniclastic rocks. They are grouped into garnet-1 (low w/r) and garnet-2 (inverse zoning at high w/r) with notable Cu-contents (up to 743 ppm). Petrographically, magnetite morphology is divided into fine-grained granular, needle-like, and polycrystalline aggregates. Mineral chemistry of needle-like type reveals impure components (Al2O3, CaO, and SiO2). This type formed from dissolution-reprecipitation processes during a stage of reequilibration in the skarn system. Mixing with cooler external fluid (rich in oxygen and poor in Fe2+) is reflected in individual features during infiltration metasomatism during garnet and magnetite growth, such as oscillatory zoning and needle-like textures. Thus, we infer increasing pH (decreasing acidity) and decreasing T related to carbonate neutralization reactions affecting Fe- and Cu-chloride complexing as the main controls on mineralization. The structural studies of the area show that movement of the dextral transtensional Zefreh Fault provide local zones for emplacement of Dorojin granitoid during the Early Miocene. Consequently, the dextral transtensional Zefreh Fault and dextral transpression associated with the Marbin-Rangan Fault uplifted the skarn and host units and Dorojin body under the roughly N-S directed maximum compression direction. Furthermore, the interplay of Zefreh and Marbin-Rangan faults within the N-S regional compressional regime formed an anticlinal structure that exposed the Dorojin body within the core.

Metallogenesis and fluid evolution of the Huangtupo Cu–Zn deposit, East Tianshan, Xinjiang, NW China: Constraints from ore geology, fluid inclusion geochemistry, H–O–S isotopes, and U–Pb zircon, Re–Os chalcopyrite geochronology

Year: 2020
Products: NWR193;ESI;
Authors: Cheng, X;Yang, F;Zhang, R;Xu, Q;Li, N;
Journal: Ore Geology Reviews

The recently discovered Huangtupo Cu–Zn deposit is located in the Dananhu–Tousuquan arc, East Tianshan, NW China. Orebodies are hosted in volcano-sedimentary rocks of the Late Ordovician–Early Silurian Daliugou Formation. The metallogenic physicochemistry, ore-forming fluids, and metallogenesis of the deposit were investigated through orebody features, fluid inclusion microthermometry, laser Raman spectroscopy, and synchrotron-radiation X-ray fluorescence (SRXRF). The results indicate that the deposit includes an upper sedimentary exhalative ore belt (stage I) as well as a lower vein-stockwork ore belt in a hydrothermal fluid supply channel (stage II) associated with silicification, chloritization, epidotization, pyrophyllitization, and beresitization alteration. The Re–Os isochron age of 429.5 ± 10 Ma obtained from primary chalcopyrite. The LA-ICP-MS zircon U–Pb age of 423.3 ± 2.9 Ma for the host hangingwall tuff. Fluid inclusion (FI) microthermometry and geological characteristics were applied to constrain hydrothermal processes and ore genesis. Quartz and barite were collected from the massive sulfide and vein ores for FI study. Four types of FI were identified: liquid-rich L-type, vapor-rich V-type, daughter-mineral-bearing S-type, and C-type containing CO2–H2O. Stage I barite FIs yield homogenization temperatures of 232–364 °C (peak value 265 °C), with salinities of 4.85–10.94 wt% NaCl equiv., whereas stage II quartz FIs yield temperatures of 270–400 °C (peak value 350 °C), with salinities of 2.41–13.72 wt% NaCl equiv (peak value 6.28 wt%). Laser Raman spectroscopy analyses of FI gas compositions indicate that the FIs contain mainly H2O with minor CO2 and N2. Initial ore-forming fluids comprise a medium-high-temperature, low-salinity system of hot evolved seawater that was cooled and diluted by mixing with cold seawater. Fluid mixing and local boiling would have facilitated mineralization. SRXRF analyses indicate that the liquid phase is enriched in Cu and Zn. The δ34S values of sulfide indicate that the sulfur was derived from the magma (host volcanic rocks). Oxygen and hydrogen isotopic data also imply that the ore-forming fluids were mainly derived from deep circulation of seawater, and mixed with minor magmatic fluids. The estimated trapping pressures for vein-stockwork mineralization fluids range from 20 to 60 bar (average 40 bar) at a depth of ~0.4 km. The ore fluids ascenting along faults and fracture networks at or near the seafloor played important roles in oreforming processes of the Huangtupo VMS Cu–Zn deposit.

Geochronological, geochemical, and mineralogical characteristics of the Akechukesai-I mafic–ultramafic complex in the eastern Kunlun area of the northern Tibet Plateau, west China: Insights into ore potential

Year: 2020
Products: UP213;New Wave;NewWave;
Authors: Yan, J;Sun, F;Li, B;Li, L;Zhang, W;Yan, Z;Zhang, Y;
Journal: Ore Geology Reviews

The recently discovered Akechukesai mafic–ultramafic complex is located in the East Kunlun Orogenic Belt, northern Tibet Plateau, China. Two mafic–ultramafic complexes (Akechukesai I and Ⅱ) intrude marble of the Cambrian–Ordovician Tanjianshan Group. Cu–Ni sulfide mineralization occurs in these complexes. Pyroxenite in the Akechukesai-I complex has an age of 422 ± 10 Ma(1σ), similar to that of the Xiarihamu and Shitoukengde Cu–Ni deposits of the East Kunlun area. The positive εHf(t) values (1.7–4.9) and SiO2, TiO2, and Al2O3 contents of clinopyroxene from pyroxenite suggest that the parental magma of the Akechukesai-I complex was derived from depleted mantle composed of garnet lherzolite and spinel lherzolite in varying proportions. Pyroxenite of the Akechukesai-I complex has (87Sr/86Sr)i ratios of 0.70993–0.71405, εNd(t) values of −1.97 to −6.64, (206Pb/204Pb)i ratios of 17.113–18.994, (207Pb/204Pb)i ratios of 15.548–15.673, and (208Pb/204Pb)i ratios of 37.066–38.650, which together indicate a depleted mantle source with 18–35 wt% upper-crustal contamination. δ34S values of sulfide minerals are 5‰–11.5‰ with S/Se ratios of ore-bearing pyroxenite being in the range 3738–15,501, both being higher than mantle values (−2‰ to +2‰ and 2850–4350, respectively) and indicating the addition of crustal S. The incorporation of primitive magma into the marble host during ascent caused a reduction in sulfide solubility owing to increased oxygen fugacity of the magma, leading to S saturation. These observations and the geodynamic setting indicate that the complex is a favorable environment for mineralization.

Petrogenesis of Late Carboniferous intrusions in the Linglong area of Eastern Tianshan, NW China, and tectonic implications: Geochronological, geochemical, and zircon Hf–O isotopic constraints

Year: 2020
Products: NewWave;
Authors: Sun, M;Wang, Y;Zhang, F;Lin, S;Xue, C;Liu, J;Zhu, D;Wang, K;Zhang, W;
Journal: Ore Geology Reviews

The Linglong porphyry Cu deposit is located in the Dananhu–Tousuquan Arc Belt, adjacent to the large Tuwu–Yandong Cu deposits in Eastern Tianshan, northwest China. In this study, zircon U–Pb, whole rock geochemistry, and zircon Hf–O isotopic analyses were carried out on the Linglong intrusions (i.e., quartz albite porphyry and diorite porphyry). New SIMS zircon U–Pb dating and previous data indicate that the quartz albite porphyry occurred in the Late Carboniferous (318.6 ± 3.0 Ma), younger than emplacement of the diorite porphyry (338–340 Ma) and tonalite porphyry (332–335 Ma) in this area, as well large-scale copper mineralization (331–335 Ma) in Eastern Tianshan. The geochemistry of the quartz albite porphyry intrusions is consistent with calc-alkaline normal arc magmatism, characterized by high SiO2 (74.82–77.89 wt%), obvious Eu anomalies (0.42–0.52), high Y (21–25.9 ppm) and Yb (2.98–3.67 ppm) concentrations, moderate Mg# values (35–40), but relatively low Sr/Y (6.86–9.52)and low 10,000 Ga/Al values. In situ Hf–O isotopic analyses on zircons show that the quartz albite porphyry rocks have variable εHf(t) (+9.0 to + 13.9) and low δ18O values (4.72 to 5.84‰), suggesting a juvenile lower crust derived composition. However, the diorite porphyry intrusions show features of low SiO2 (57.51–61.12 wt%), minor Eu anomalies (0.82–1.15), strong depletion in high field strength elements (e.g., Nb, Ta, P and Ti), but enrichment in large ion lithophile elements (e.g., Rb, Ba, K and Pb). They also exhibit normal island arc magma geochemical signatures, with high Y (20.9–40.2 ppm), and Yb (2.75–4.64 ppm) concentrations, high Mg# (40–51), and relatively low (La/Yb)N (2.07–4.10) and Sr/Y (5.75–12.13) values, suggesting the melt was derived from the subduction-modified mantle mafic to ultramafic materials. Combined with regional tectonic evolution and our new data, we suggest that the Late Carboniferous magma was generated during the period of the northward subduction of the Paleo-Tianshan ocean plate beneath the Dananhu–Tousuquan island arc.

Genesis of the giant Caixiashan Zn-Pb deposit in Eastern Tianshan, NW China: Constraints from geology, geochronology and S-Pb isotopic geochemistry

Year: 2020
Products: UP213;NewWave;
Authors: Gao, R;Xue, C;Chi, G;Dai, J;Dong, C;Zhao, X;Man, R;
Journal: Ore Geology Reviews

The Caixiashan Zn-Pb deposit is the largest carbonate-hosted Zn-Pb deposit in Eastern Tianshan, NW China. The deposit comprises the No. Ⅰ, Ⅱ, III and IV ore zones with a proven reserve of 131 Mt ore at 3.95% Pb + Zn. The orebodies generally occur as irregular lenses and pods in altered carbonate rocks of the Mesoproterozoic Kawabulake Group near faults. The mineralization is characterized by massive, disseminated and vein/veinlet sulfides including pyrite, pyrrhotite, sphalerite and galena with minor arsenopyrite and chalcopyrite, as well as sulfosalt minerals of Ag, As, Sb and Pb. The mineralization is associated with tremolite, chlorite, silica and carbonate alterations. Rb-Sr isotopic dating of sphalerite and pyrrhotite yields an isochron age of 337.2 ± 5.7 Ma, which is interpreted as the mineralization age. Zircon U-Pb dating reveals that stocks of diorite, quartz diorite, K-feldspar granite and monzonitic granite that occur in the deposit area were emplaced at 348.2 ± 3.7 Ma, 351.9 ± 3.5 Ma, 333.6 ± 3.6 Ma and 330.0 ± 3.6 Ma, respectively. These age data suggest that the mineralization is coeval with Carboniferous granitic magmatism. The δ34SV-CDT values of sulfides (excluding the syn-sedimentary pyrite) range from −2.42‰ to 19.1‰, suggesting that the reduced sulfur was mainly derived from thermal sulfate reduction (TSR) of seawater-derived sulfates in the marine sedimentary basement rocks and minor contribution by replacement of syn-sedimentary pyrite, as well as a possible input of magmatic sulfur. The Pb isotopic compositions of sulfides, with 206Pb/204Pb ranging from 17.074 to 17.361, 207Pb/204Pb from 15.422 to 15.614, and 208Pb/204Pb from 36.685 to 37.303, partly overlap with those of basement rocks of the Mesoproterozoic Kawabulake Group and the Carboniferous intrusions, suggesting that the ore metals were derived from both the basement and Carboniferous magmatism. On the basis of the spatio-temporal relations between hydrothermal alterations/mineralization and Carboniferous magmatism, we conclude that the Caixiashan Zn-Pb deposit is a high-temperature carbonate replacement deposit related to concealed granitic intrusions, which were formed in an arc environment related to the subduction of the South Tianshan Ocean plate beneath the Central Tianshan massif during the Carboniferous time. The results of this study indicate that there is a great potential of finding more large-scale Zn-Pb deposits similar to Caixiashan in Eastern Tianshan.

Mineralogical and isotope-geochemical (δ13C, δ34S and Pb-Pb) characteristics of the Krasniy gold mine (Baikal-Patom Highlands): Constraining ore-forming mechanisms and the model for Sukhoi Log-type deposits

Year: 2020
Products: UP213;New Wave;
Authors: Tarasova, Y;Budyak, A;Chugaev, A;Goryachev, N;Tauson, V;Skuzovatov, S;Reutsky, V;Abramova, V;Gareev, B;Bryukhanova, N;Parshin, A;
Journal: Ore Geology Reviews

Orogenic gold deposits localized in carbonaceous sedimentary (black-shale) complexes are major contributors to worldwide balance of gold extracted from the crust, though there is a limited consensus about the role of host sedimentary rocks, involvement of external (i.e., magma-derived) fluids and brittle deformations into ore remobilization and transport. This paper presents the original results of mineralogical, petrographic and isotope-geochemical studies of rocks and ores from the large Krasniy gold deposit (Baikal-Patom plateau, southern Siberian craton) given in comparison with the thoroughly studied giant Sukhoi Log deposit, with both deposits hosted by the Neoproterozoic carbonaceous metasedimentary rocks. The multi-stage ore process occurred discretely at 200–400 °C (greenschist-facies metamorphism) and included (1) low-P-T diagenetic formation of globular pyrite, (2) catagenetic (<200 °C, 1–2 kbar) formation of small euhedral pyrite, (3) high-temperature and high-pressure (300–380 °C, 5–6 kbar) crystallization of arsenopyrite and pyrrhotite related to metamorphic transformation, and (4) formation of the major ore assemblage (arsenopyrite, pyrrhotite, pyrite meta-aggregates, native gold, galena, sphalerite, fahl ores) during almost isothermal decompression (270–320 °C, 0.5 kbar). Gold is detected as nanoparticles unevenly distributed at the surface of the early globular pyrite (up to 0.4 ppm) and occurs as inclusions in later metamorphic pyrite. Relatively narrow ranges of sulfur (δ³⁴S within −4.7 – −6.9‰) and lead isotopic composition (²⁰⁶Pb/²⁰⁴Pb = 18.33–18.65, ²⁰⁷Pb/²⁰⁴Pb = 15.65–15.68 and ²⁰⁸Pb/²⁰⁴Pb = 38.13–38.82) in sulfides from the ores was continuously inherited from earlier generation of sulfides to the later (associate with native gold) and is similar to the values obtained for sulfides from the host Neoproterozoic metasedimentary rocks of the Aunakit formation. The compositional inheritance together with geochemical evidence of no additional contribution of К, Na, Mg and Si into the ores and no correlation between gold and organic carbon content highlight the absence of the external metasomatic overprint of metal-bearing fluids. Instead, both the above facts and high Au content (up to 1 ppm) in bitumens derived from the host metasediments indicate a key role of the host carbonaceous substrate in the supply of metals through release and local transport of internally derived diagenetic/catagenetic carbon-rich fluids. Overall, the obtained results for the Krasniy deposit led to distinguishing the three key stages of the gold deposit formation, including 1) sedimentation of gold-specialized sediments in the spreading of the back-arc basin, where gold was associated with the scattered diagenetic pyrite mineralization (610–590 Ma), 2) catagenetic redistribution of sedimentary pore fluids from preconditioned sedimentary rocks into the vaulted parts of gentle anticlines with the formation of abnormally high concentrations of gold (~570 Ma), and 3) metamorphic-metasomatic redistribution of gold as a result of decarbonization of catagenic fluid with the formation of economically significant ore bodies (450–420 Ma). The compilation of the available geochemical and isotopic data allows to suspect this model as a general for the other Bodaibo region deposits, so that it can be used further for prediction and exploration purposes.

Molybdenite Re-Os dating and LA-ICP-MS trace element study of sulfide minerals from the Zijinshan high-sulfidation epithermal Cu-Au deposit, Fujian Province, China

Year: 2020
Products: NWR213;New Wave;New Wave Research;Electro Scientific Industries;ESI;
Authors: Zhao, X;Zhong, H;Mao, W;Bai, Z;Xue, K;
Journal: Ore Geology Reviews

The Zijinshan Cu-Au deposit, located in Fujian Province, is the largest high-sulfidation epithermal (HSE) deposit in Southeastern China and is usually regarded as a major part of the porphyry Cu system in the Zijinshan ore field. Molybdenite samples collected from the Cu mineralization zone yield a first weighted mean Re-Os age of 111.31 ± 0.70 Ma, which is explained as the time of dickite-alunite alteration. Combining the newly reported muscovite 40Ar-39Ar and zircon U-Pb ages (~113 Ma), the mineralization of Zijinshan is likely to initiate before ca. 110 Ma. This result is obviously older than the Re-Os age of the adjacent Luoboling porphyry Cu-Mo deposit (~105 Ma). Pyrite, chalcopyrite, bornite, digenite, and covellite collected from the deep potassic, middle phyllic and upper epithermal zones are used to conduct LA-ICP-MS trace element analysis. The spatial zonings of mineralization and alteration and the regular variations of trace elements in sulfides at vertical direction imply a potentially complete transition from porphyry to epithermal mineralization and the deep origin of ore-forming fluids. Mineralogical and trace element characteristics indicate that the chalcopyrite formed in both stages, whereas bornite is the product of epithermal mineralization, rather than a porphyry stage residue. The majority of digenite and covellite has hypogene genesis. Pyrite and digenite in the epithermal zone are major carriers of primary Au. Au in pyrite is Te-Bi related and exists as solid solutions or different-sized telluride and Bi-sulfosalt inclusions. Compared to As, Te and Bi played more important roles to scavenge Au and Ag and achieve the primary Au enrichment. Differently, Au in digenite is independently locked in digenite lattice. Bornite and digenite are good carriers of primary Ag, which mainly exists as solid solutions. The high sulfidation state stage is the major period for concentrations of primary Au and Ag. The upward increase of Au in primary sulfides of HSE Cu zone implies that the distribution pattern of upper Au enrichment and lower Cu enrichment is not only caused by supergene process, but is also controlled by hypogene trend. Based on the mineralization and alteration zonings, the spatial variation of trace elements and the presented Re-Os age, the ore-forming fluids of the Zijinshan Cu-Au deposit most likely originate from deep region, rather than from the adjacent Luoboling porphyry deposit. The Zijinshan and the Luoboling deposits should belong to two independent hydrothermal systems.

Petrogenesis and tectonic setting of igneous rocks from the Dongbulage porphyry Mo deposit, Great Hinggan Range, NE China: Constraints from geology, geochronology, and isotope geochemistry

Year: 2020
Products: UP213;New Wave;
Authors: Guo, X;Li, J;Zhang, D;Xue, F;Xian, H;Wang, S;Jiao, T;
Journal: Ore Geology Reviews

The Dongbulage porphyry Mo deposit is a recently discovered deposit located in the Huanggang–Ganzhuermiao polymetallic metallogenic belt of Inner Mongolia, NE China. Here, we present zircon U–Pb ages and Hf isotopic compositions, and whole-rock geochemical and Sr–Nd–Pb isotopic data, for magmatic rocks associated with Mo mineralisation to constrain the age and petrogenesis of these rocks. The rocks are dominated by mineralised granite porphyries, quartz-monzonites, and rhyolite. Zircon U–Pb dating shows that the ore-bearing granite porphyries have ages of 154.4 ± 3.5, 155.4 ± 1.1, and 158.7 ± 0.6 Ma, the quartz-monzonites have ages of 157.8 ± 1.6 and 166.5 ± 1.3 Ma, and the rhyolite has an age of 172.9 ± 3.0 Ma. The granite porphyries and rhyolites are characterised by high K2O and SiO2 contents, enrichment in light rare-earth elements, strong negative Eu anomalies, and pronounced depletion in Ba, Nb, Ta, Sr, P, and Ti. The quartz-monzonites show enrichment in large-ion lithophile elements (Rb and K), are depleted in heavy rare-earth elements, Nb, Ta, Sr, P, and Ti, and exhibit weak negative Eu anomalies. All of the rocks have low initial 87Sr/86Sr (0.7022–0.7064) and εNd(t) values (−3.62 to + 3.99), positive εHf(t) values (+1.1 to + 13.8), and young two-stage Nd and Hf model ages (TC DM(Nd) = 623–1240 Ma and TC DM(Hf) = 305–1108 Ma, respectively). Whole-rock Pb isotopic compositions show a narrow range of values, with 206Pb/204Pb = 18.314–19.116, 207Pb/204Pb = 15.573–15.595, and 208Pb/204Pb = 38.731–39.296, which, together with their Sr–Nd–Hf isotopic compositions, indicate the dominance of a mantle source component. The isotopic data suggest that the Dongbulage magmatic rocks were derived from partial melting of juvenile lower crust. The granite porphyries are highly evolved I-type magmas with geochemical characteristics similar to those of porphyry granitoids associated with Mo mineralisation in the Great Hinggan Range. On the basis of the regional geology and geochemistry, we suggest that the Dongbulage porphyry Mo deposit formed in a subduction setting associated with southward subduction of the Mongol–Okhotsk oceanic plate.

Formation of the Fanshan lithocap and implications for exploration in the Luzong Basin, Anhui Province, China

Year: 2020
Products: New Wave;
Authors: Li, X;Zhou, T;White, N;Fan, Y;Zhang, L;Xie, J;Liu, Y;Xiao, X;
Journal: Ore Geology Reviews

Lithocaps in island-arc settings are genetically related to porphyry-epithermal systems and can be used to guide exploration for porphyry deposits. The Fanshan area of the Luzong basin in the eastern China, hosts a large lithocap but no porphyry or epithermal deposits have been found. The Fanshan lithocap in the Luzong basin is centred on the Dafanshan alunite mining district with vuggy quartz–alunite–pyrite, quartz–dickite–kaolinite ± alunite, quartz–kaolinite and kaolinite–illite ± smectite from northeast to southeast. The alteration zoning reflects the gradual decrease in the temperatures and acidities of the fluids. Four types of alunite including bladed alunite, needle alunite, granular alunite, and powdery alunite suggest that the Fanshan lithocap formed in the magmatic-hydrothermal and supergene environment. From the southwest to the northeast of the Dafanshan district, Pb and 106Pb/(Na + K) in the alunite samples gradually decrease, Au content gradually increases, but the Cu content does not change significantly. The peak positions at 1480 nm and the Na content of the magmatic-hydrothermal alunite gradually increase, whereas Pb and 106Pb/(Na + K) in the alunite minerals gradually decrease. This suggests that the source of the hydrothermal fluids and a potential zone of precious metal mineralization area may be in the northeast of the Dafanshan district, and the potential area of copper mineralization may be in the Huangtun area northeast of the Luzong basin.

LA-ICP-MS trace element analysis of magnetite and pyrite from the Hetaoping Fe-Zn-Pb skarn deposit in Baoshan block, SW China: Implications for ore-forming processes

Year: 2020
Products: UP213;New Wave;
Authors: Chen, F;Deng, J;Wang, Q;Huizenga, J;Li, G;Gu, Y;
Journal: Ore Geology Reviews

The Hetaoping deposit is one of the largest Fe-Zn-Pb skarn deposit in SW China, which is characterized by Zn-Pb mineralization in the upper part and the Fe mineralization in the deeper part. The Fe mineralization is dominated by magnetite and pyrite. Magnetite can be subdivided into four types: primary banded magnetite samples in clinopyroxene-actinolite skarn (Mt-1), primary disseminated magnetite in garnet skarn (Mt-2), primary disseminated magnetite in clinopyroxene-actinolite skarn (Mt-3), and altered magnetite in clinopyroxene-actinolite skarn (Mt-4). Pyrite can be subdivided into three types: pyrite in oxide-ore stage (Py-1), pyrite in early sulfide-ore stage (Py-2), and pyrite in late sulfide-ore stage (Py-3). The flat time-resolved signals of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) imply that trace elements exist mainly in the form of isomorphism in magnetite and pyrite with the exception some incompatible trace elements (e.g., Ca, K and Na in magnetite and Pb, Bi and Ag in pyrite). Trace element concentrations in magnetite and pyrite demonstrate that the ore-forming fluid in Hetaoping is of magmatic origin. Furthermore, compared to porphyry, IOCG, Kinuna and BIF type magnetite, the magnetite from Hetaoping has relatively low Ti, V and Ni concentrations but high Al, Mn and Ca concentrations, implying a typical skarn genesis. The variation of Ti concentrations in magnetite is an indication of the formation temperature and shows that banded magnetite (Mt-1) precipitated in a relatively high-temperature environment compared with disseminated magnetite (Mt-2 and Mt-3). Compared to Mt-1 and Mt-3, Mt-2 has a higher Si, Al, and W contents and a lower Mg and Mn contents. The Mn content increases from Py-1 to Py-2, and decreases from Py-2 to Py-3, suggesting that the fluid-rock interaction increased from the oxide-ore stage to the sulfide-ore stage, and decreased from sulfide-ore stage to post-ore stage. The variation of the V concentration in magnetite grains indicates a relatively higher oxygen fugacity of Mt-2 compared to Mt-1 and Mt-3, implying that the oxygen fugacity of the ore-forming fluid in the garnet skarn zone is higher than that in clinopyroxene-actinolite skarn zone. The variable oxygen fugacity probably caused spatial zoning of mineralization in Hetaoping Fe-Zn-Pb skarn deposit. The temperature and oxygen fugacity of the ore-forming fluid, and the extent of fluid-rock interaction, controlled the temporal order and spatial zonation of magnetite and sulfide precipitation, which led to the formation of the Hetaoping Fe-Zn-Pb skarn deposit.

Silicate-carbonate liquid immiscibility: insights from the Crevier alkaline intrusion (Quebec)

Year: 2020
Products: NWR193UC;ESI;
Authors: Groulier, P;Turlin, F;André-Mayer, A;Ohnenstetter, D;Crépon, A;Boulvais, P;Poujol, M;Rollion-Bard, C;Zeh, A;Moukhsil, A;Solgadi, F;El Basbas, A;
Journal: Journal of Petrology

This contribution explores the petrogenetic relationships between silicate and carbonatitic rocks in the Crevier Alkaline Intrusion (CAI, Québec, Canada). The CAI is located in the Proterozoic Grenville Province and is composed of a suite of undersaturated peralkaline rocks from ijolite to nepheline syenite and carbonatites. Petrogenetic relationships between different undersaturated alkaline igneous rocks, carbonate-bearing and carbonate-free nepheline syenite and carbonatites observed in the CAI suggest that (i) carbonate-bearing and carbonate-free silicate rocks are comagmatic with carbonatite, and that (ii) both silicate and carbonatitic liquids are fractionated from an ijolitic parental magma that has undergone liquid immiscibility. One of the observed facies is characterized by spectacular ocelli of carbonate-bearing nepheline syenite in a matrix of carbonatite. The younger nepheline syenite facies can be divided into two groups based on the presence or absence of magmatic carbonates. Both groups are characterized by the presence of pyrochlore-group minerals that carry the Nb-Ta mineralization. We specifically use accessory minerals such as zircon, pyrochlore and apatite to constrain the temporal and physicochemical parameters of the immiscibility process. By coupling (i) mineral textures, (ii) trace elements, (iii) Ti-in-zircon thermometry, and (iv) oxygen isotope compositions, we have traced the crystallization of zircon before, during and after the immiscibility process. The results allowed us to constrain the minimum temperature of this process at ∼815-865 °C. In addition, two magmatic populations of pyrochlore are identified through their petrographic and geochemical characteristics within the younger nepheline syenite facies. Pyrochlore from the earlier ocelli facies of carbonate-bearing nepheline syenite follow a Nb-Ta differentiation trend, whereas pyrochlore from the younger carbonate-free nepheline syenite follow a more classical Nb-Ti trend. Following the complete immiscibility between the silicate and carbonatitic liquids, the fractionation between Nb and Ta stopped while a new generation of Nb-rich pyrochlore grew, displaying a more classical Nb-Ti fractionation trend and a more constant Nb/Ta ratio in the nepheline syenite.

Comparative geothermometry in high-Mg magmas from the Etendeka Province and constraints on their mantle source

Year: 2020
Products: UP213;New Wave;New Wave Research;
Authors: Cheng, Z;Hou, T;Keiding, J;Veksler, I;Kamenetsky, V;Hornschu, M;Trumbull, R;
Journal: Journal of Petrology

There is still debate whether Large Igneous Provinces (LIPs) are caused by high mantle temperatures induced by thermal plumes or by other factors that enhance melt production from the mantle. A prerequisite for assessing the thermal plume model is a reliable estimate of liquidus temperatures of the magmas produced, preferably based on more than one method of geothermometry. The study reported here compares multiple geothermometers for the Etendeka LIP, which is among the largest Phanerozoic examples and one that shows several features suggestive of a plume origin (continental flood basalt province linked via an age-progressive volcanic ridge to an active hotspot). Magnesium (Mg)-rich magmas emplaced as dikes in NW Namibia are the most primitive rocks known from this province and are thus best suited to determine the composition and melting conditions of their mantle source. Earlier studies of the Etendeka Mg-rich dikes reported high liquidus temperatures based on olivine-melt Mg-Fe equilibria. We extend that work to a larger set of samples and compare the results of olivine-melt Mg-Fe thermometry with other methods based on spinel-melt and spinel-olivine equilibria (Al-in-olivine thermometry), as well as olivine-melt trace-element exchange (Sc/Y thermometry and V oxybarometry). All methods used the same starting assumptions of nominally anhydrous melts and a crystallization pressure of 0.5 GPa. Only mineral-melt or mineral-mineral pairs consistent with compositional equilibrium were used for calculating temperatures. The trace-element compositions of olivine are also used to discuss the relative proportion of peridotite and pyroxenite in the mantle source for these magmas. Twelve dike samples were studied, with whole-rock MgO concentrations ranging from 8.4 to 19.4 wt.%. Diagnostic element ratios of transition metals in olivine (e.g., Mn/Fe, Mn/Zn, Zn/Fe) indicate a peridotite–dominated mantle source for the magmas, which is consistent with the other indicators based on whole-rock data e.g., 10000×Zn/Fe, CaO-MgO trend, FeO/MnO and FC3MS (FeO/CaO–3×MgO/SiO2). The temperature variations show a positive correlation with the Fo-content of host olivines, and values from high-Fo olivine agree well with olivine and spinel liquidus temperatures calculated from thermodynamic models of bulk-rock composition. All methods and most samples yielded a temperature range between 1300 °C and 1400 °C. An exceptional few samples returned temperatures below 1300 °C, the minimum being 1193 °C, whereas several samples yielded temperatures above 1400 °C, the upper range being 1420-1440 °C, which we consider to be a robust estimate of the maximum liquidus temperatures for the high-Mg magmas studied. The conversion to mantle potential temperatures is complicated by uncertain depth and degree of melting, but the functional relationship between Tp and primary melt MgO contents, using melt inclusions from olivine phenocrysts with of Fo &gt; 90, indicate a Tp range from 1414 to 1525 °C ( 42 °C), which is 100-150 °C higher than estimates of ambient upper mantle Tp in the South Atlantic today.

Natal origin of Pacific bluefin tuna from the California Current Large Marine Ecosystem

Year: 2020
Products: NWR193UC;
Authors: Wells, RJD;Mohan, JA;Dewar, H;Rooker, JR;Tanaka, Y;Snodgrass, OE;Kohin, S;Miller, NR;Ohshimo, S;
Journal: Biol. Lett.

Natal origin of subadult (age-1) Pacific bluefin tuna (PBT, Thunnus orientalis) from the California Current Large Marine Ecosystem (CCLME) was determined using natural tracers in ear stones (otoliths). Age-0 PBT collected from the two known spawning areas in the western Pacific Ocean (East China Sea, Sea of Japan) were used to establish baseline signatures from otolith cores over 4 years (2014-2017) based on a suite of trace elements (Li, Mg, Mn, Sr, Zn and Ba). Distinct chemical signatures existed in the otolith cores of age-0 PBT collected from the two spawning areas, with overall classification accuracy ranging 73-93% by year. Subadult PBT collected in the CCLME over the following 4 years (2015-2018) were then age-class matched to baselines using mixed-stock analysis. Natal origin of trans-Pacific migrants in the CCLME ranged 43-78% from the East China Sea and 22-57% from the Sea of Japan, highlighting the importance of both spawning areas for PBT in the CCLME. This study provides the first estimates on the natal origin of subadult PBT in this ecosystem using otolith chemistry and expands upon the application of these natural tracers for population connectivity studies for this species.

Detrital zircon U–Pb geochronology and Lu–Hf isotopic analysis of the Neoproterozoic Penglai Group and their comparisons with coeval sedimentary strata of the southeastern North China Craton: provenance, tectonic affinity and implications

Year: 2020
Products: UP213;New Wave;
Authors: Liu, J;Ding, Z;Wang, X;Chen, H;Liu, F;
Journal: Journal of the Geological Society

The results of U–Pb dating and Hf isotopic analyses of detrital zircons from the Penglai Group in the Jiaobei terrane of the North China Craton (NCC) gave age populations of 1300–1000, 1500–1300, 1700–1500, 1800–1700 and >1800 Ma. The age spectra, variations in U and Th contents, Th/U ratios and Hf isotopic compositions of the detrital zircons of the Penglai Group are identical to those of the Tonian strata of the southeastern NCC. The Penglai Group rocks also have a similar litho- and biostratigraphy and tectonic setting to these Tonian strata, suggesting that the Penglai Group has a tectonic affinity with the NCC and was deposited during the Tonian. The detrital zircon age populations of the Penglai Group are consistent with the multiple magmatic and thermal metamorphic events in the NCC, especially the 1300–1000 Ma intermediate–acid and/or acid igneous rocks of the Korean Peninsula, and we therefore propose that the Penglai Group is mainly sourced from the NCC. The detrital zircon populations of 1300–1000, 1500–1300, 1700–1500 and 1800–1700 Ma show both positive and negative εHf(t) values, which, combined with late Paleoproterozoic–Neoproterozoic basic magmatism represented by large volumes of diabase sills in the NCC, suggests that the NCC experienced strong crust–mantle interactions that might have triggered continuous, multi-stage rifting in the NCC during the late Paleoproterozoic (1.8 Ga)–Neoproterozoic.

Vapor Transport and Deposition of Cu-Sn-Co-Ag Alloys in Vesicles in Mafic Volcanic Rocks

Year: 2020
Products: NWR193;
Authors: Hunter, E;Hunter, J;Zajacz, Z;Keith, J;Hann, N;Christiansen, E;Dorais, M;
Journal: Economic Geology

Metallic sublimates coated by sulfides and chlorides line the vesicle walls of mafic volcanic lava and bombs from Kīlauea, Vesuvius, Etna, and Stromboli. The metallic sublimates were morphologically and compositionally similar among the volcanoes. The highest concentrations of S and Cl occurred on the surface of the sublimates, while internally they had less than 1 wt % S and Cl in most cases, leading us to classify them as alloys. The major components of the alloys were Cu, Sn, Co, and Ag based on electron microprobe analyses and environmental scanning electron microscope element maps. Alloy element maps showed a covariance of Cu-Sn, while Co and Ag concentrations varied independently. Laser ablation-inductively coupled plasma-mass spectrometry analysis of matrix glass and melt inclusions in bombs from Stromboli showed appreciable amounts of Cu, Co, and Sn. We propose a model for the origin of the metallic grains, which involves syneruptive and posteruptive magma degassing and subsequent cooling of the basalt vesicles. During syneruptive vapor phase exsolution, volatile metals (Cu, Co, and Sn) partition into the vapor along with their ligands, S and Cl. The apparent oxygen fugacity (fO2) in these vapor bubbles is low because of the relative enrichment of the exsolved gas phase in H2 relative to H2O in silicate melts, due to the much higher diffusivity of the former in silicate melts. The high fH2 and low fO2 induces the precipitation of metal alloys from the vapor phase. Subsequently, the reducing environment in the vesicle dissipates as the cooling vapor oxidizes and as H2 diffuses away. Then, metal-rich sulfides (and chlorides) condense onto the outer surfaces of the metal alloy grains either due to a decrease in temperature or an increase in fO2. These alloys provide important insights into the partitioning of metals into a magmatic volatile phase at low pressure and high temperature.

Application of Computed Tomography in the analysis of the manufacture of eye beads technique

Year: 2020
Products: New Wave;
Authors: Xueyan, Z;Yong, L;Qian, C;Guangzhao, Z;
Journal: Microchemical Journal

In the study of archaeological glass beads, the manufacturing process of eye beads is of great significance and value. This is a focused research investigation about eye beads. Based on previous research published 2019 [3], one of the eye beads unearthed in Shampula Cemetery was proved to be embedded manufacture. In this paper, several kinds of eye beads were studied and compared. With the results, a new manufacturing process for certain eye beads is discovered and compared by X-ray Computed Tomography (CT) technique. The shapes of air bubbles, the distribution of the air bubbles, and especially the direction of the eye part in the beads, were analyzed by CT. Two kinds of pattern of eyes were discovered based on the CT results and the appearance of specific eye beads. Thus, the manufacturing process of eye beads can be divided into two types. The difference between the two types is the placement direction of the eye parts. In addition, the manufacturing process of eyes produced either raised or embedded appearances of the eye beads. The squeezing direction was found to be perpendicular to the long axis of the elliptical bubbles in the bead body through the air bubble shape of the three samples producing raised eye beads and embedded eye beads which appear like human eyes. Analysis of the technological factors produced insights into the beads-making process within a historical context so as to provide better data for the origin of this particular batch of eye beads.

Habitat Use Patterns and Identification of Essential Habitat for an Endangered Coastal Shark With Vertebrae Microchemistry: The Case Study of Carcharhinus porosus

Year: 2020
Products: NWR213;New Wave;New Wave Research;ESI;
Authors: Feitosa, L;Dressler, V;Lessa, R;
Journal: Front. Mar. Sci.

Sharks are among the most endangered and data poor vertebrates in the world. The lack of information regarding their habitat use is especially concerning since these are crucial for the establishment of priority areas for species conservation. Investigating the trace elements present in shark vertebrae has become an interesting tool to analyze species habitat use over individuals’ lifetimes. Therefore, we applied vertebrae microchemistry to investigate habitat use of Carcharhinus porosus in Brazil’s Northern Coast (BNC). We also discuss methodological issues that must be addressed in the future to make microchemistry studies with elasmobranchs at low latitudes more robust. Vertebrae from seventeen individuals sampled in the 1980s (n = 8), and in 2017 and 2018 (n = 9) were evaluated through laser ablation inductively coupled plasma mass spectrometry. We analyzed five elements known to reflect environmental characteristics (Ba, Ca, Mg, Mn, and Sr) by sex, seasons, decades of capture, and life stages. Since Ca is the most abundant element in the vertebrae, we calculated element:Ca ratios and employed these proportions for all statistical analysis. We also used fisheries-independent catch data from the 1980s to test if the BNC is a nursery area for C. porosus. We found significant differences in element concentrations between sexes in both multi and single-element analysis, while decades differed only in the multi-element and Sr:Ca. Furthermore, seasons differed in both multi-element and Mg:Ca and Ba:Ca ratios. We did not find differences between life stages. Neonate multi-element signatures yielded three major groups, thus suggesting that the species has at least three birthing grounds in the area. Despite the occurrence of individuals of all sizes, adults show a more distinct occurrence pattern. Our results point toward the hypothesis that the BNC is an essential habitat for this species since its whole life cycle occurs in this area. Therefore, the BNC is a critical area for its conservation. We reinforce that future studies with strictly tropical species should investigate the effects of metabolism, the species’ growth rate, and the validation of other elements capable of demonstrating fine-scale changes in habitat to reduce the inherent noise in microchemistry studies.

ROMP polymer supported manganese porphyrins: Influence of C C bonds along polymer chains on catalytic behavior in oxidation of low concentration Fe2+

Year: 2020
Products: NWR213;
Authors: Li, F;Wang, X;Zhao, H;Zhang, Y;
Journal: Reactive and Functional Polymers

One unsaturated polymer support was prepared through ring opening metathesis polymerization (ROMP) of norbornene-2,3-dip-toluene sulfonate initiated by Grubbs 2nd initiator and manganese porphyrins were immobilized on polymer through transesterification reaction. To investigate the effect of CC bonds along polymer chains on the catalytic behavior, the obtained polymer supported catalyst (P-PPIXMnCl) was applied in oxidation of low concentration Fe2+ to mimic catalytic behavior of Ceruloplasmin. In the presence of P-PPIXMnCl, the conversion of Fe2+ reaches to 91.92% and 96.46% at 10 °C and 37.5 °C (body temperature), respectively. Compared to manganese porphyrins, P-PPIXMnCl can dramatically increase oxidation rate of Fe2+ and the catalytic kinetic shows that the oxidation reaction changes from second-order to third-order. Upon hydrogenation of ROMP polymer, the oxidation reaction still conforms to the second-order kinetics. Density functional theory (DFT) calculation shows that the CC bonds along polymer chains play an important role in the coordination with Fe2+ in the catalytic microenvironment. The real time morphology of supported catalysts in aqueous environment characterized by Cryo-TEM indicates that hydrogenation can shrink the morphology of polymer-water skeleton. The catalyst could be recycled six times without any significant loss in activity. The liner heterogeneous catalyst is expected to be used as drugs for treating excessive iron accumulation in the human body.

Petrogenesis and tectonic regime of two types of Neoarchaean amphibolites in the northern margin of the North China Craton

Year: 2020
Products: NWR193;ESI;
Authors: Wang, X;Deering, C;Liu, Z;Dong, X;Li, S;Xu, Z;
Journal: International Geology Review

The Neoarchaean crustal evolutionary processes of the North China Craton (NCC) provide a window to understanding the crust–mantle interaction in the Early Earth. The Jiefangyingzi amphibolites are located in the Bainaimiao arc belt, along the northern margin of the NCC. LA–ICP–MS U–Pb isotopic data reveal that the Type 1 amphibolites were formed at ~2562 Ma, and the Type 2 amphibolites were formed at ~2504 Ma, but were subsequently subjected to metamorphism at ~1889 Ma. Lu–Hf isotopic data of the Type 1 amphibolite show positive εHf(t) values (+1.2–+6.0) and TDM from 2612 Ma to 2791 Ma, suggesting a significant episode of 2.6–2.8 Ga crustal growth within the study area. Geochemically, the Type 1 amphibolites show high SiO2 contents (53.37%–55.19%), moderate LREE–enriched patterns (La/Sm)N = 2.42–3.15 and HREE–depleted patterns (Gd/Yb)N = 1.86–2.64, with negative Nb anomalies, which are similar to IAB–like rocks, suggesting that they were derived from partial melting of arc–related depleted mantle with intense subduction–related fluids metasomatism. The Type 2 amphibolites have lower SiO2 contents from 44.28% to 50.77%, and show LREE–depleted REE patterns ((La/Sm)N = 0.67–1.02), nearly unfractionated HREE patterns ((Gd/Yb)N = 0.89–1.77), with negative Nb, Th and positive Sr, Zr anomalies, which are close to N–MORB–like rocks, indicating that they were generated from partial melting of depleted mantle with slight fluid metasomatism. The geochronological, Lu–Hf isotopic and geochemical features show that the IAB–like rocks were formed in an intra–oceanic arc environment, coincide with the significant ~2.5–2.6 Ga episode of crustal growth in the NCC; The slightly younger MORB–like rocks reflect the spreading of the oceanic crust might last until ~2.5 Ga in the central zone.

Geochronology, geochemistry, and Sr–Nd–Hf isotopes of the Late Permian–Early Triassic granitoids in Eastern Kunlun Orogen, Northwest China: petrogenesis and implications for geodynamic setting

Year: 2020
Products: UP213;NewWave;
Authors: Xue, H;Sun, F;Li, L;Xin, W;
Journal: International Geology Review

The Eastern Kunlun Orogenic Belt (EKOB) in Northwest China, is an ideal area for understanding the tectonic evolution of the Palaeo-Tethys Ocean. The EKOB is marked by widespread Palaeozoic to Early Mesozoic magmatism. However, the Late Permian–Early Mesozoic tectonic evolution of the Palaeo-Tethys Ocean tectonic regime is poorly understood. Here, we report new zircon LA-ICP-MS U–Pb dating and geochemical analyses of Late Permian–Early Triassic intrusive rocks in the Xiangyanggouxi and Dageledong areas in the EKOB, Northwest China, to discuss their petrogenesis and geodynamic setting and reconstruct the tectonic evolution of Palaeo-Tethys oceanic tectonic regime. Zircon U-Pb dating results indicate that these granitoids crystallized during ca. 256–248 Ma, i.e. the Late Permian to Early Triassic. These granitoids are mainly comprised of granodiorites and monzonitic granites that possess high concentrations of SiO2 (66.81–75.98 wt.%), K2O+Na2O (6.21–7.92 wt.%), and low contents of MgO, CaO, Cr, Ni, and Mg# (<0.44). They are classified as medium- to high-K calc-alkaline and metaluminous I-type granitoids. These granitoids are rich in light rare earth elements (LREEs) and large ion lithophile elements (LILEs) and are depleted in heavy rare earth elements (HREEs) and high field strength elements (HFSEs) with arc affinity. In addition, combined with the εHf(t) values of −2.4 to +2.4 with two-stage model ages ranging from 1409 Ma to 1027 Ma, and the εNd(t) values from −3.73 to −2.95, it is suggested that the primary magma of these granitoids was derived from the partial melting of the Late Meso–Proterozoic mafic lower crust. These findings, combined with spatio-temporal distributions of regional magmatism, reveal that the Late Permian and Early Triassic granitoids formed in a continental magmatic arc setting related to the northward subduction of the Palaeo-Tethys Ocean plate beneath the EKOB-Qaidam terrane.

Middle–late permian I-type granitoids from the Diaobingshan region in the northern margin of the North China Craton: insight into southward subduction of the Paleo–Asian Ocean

Year: 2020
Products: New Wave;
Authors: Jing, Y;Ji, Z;Ge, W;Dong, Y;Yang, H;Bi, J;
Journal: International Geology Review

An integrated study of the petrology, zircon U–Pb geochronology, whole–rock geochemistry, and in situ zircon Hf isotopic compositions of middle–late Permian granitoids from the Diaobingshan region in the northern margin of the North China Craton (NCC) has been implemented, with the aim of investigating their geochronological framework, petrogenesis, and tectonic significance. The studied granitoids are widely distributed on the southern side of the Changchun–Yanji suture zone and comprise mainly monzogranite and syenogranite, with minor quartz monzonite. New zircon U–Pb data measured by laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) yield emplacement ages of 262–256 Ma, reflecting middle–late Permian magmatism. Geochemically, the rocks contain 60.53–73.33 wt.% SiO2, 12.60–18.35 wt.% Al2O3, 3.50–8.10 wt.% K2O, 0.18–0.91 wt.% TiO2, and 0.22–1.01 wt.% MgO, and exhibit weakly peraluminous (A/CNK = 0.86–1.01) and high-K calc–alkaline and shoshonitic characteristics, indicating I-type granite affinities. They are also characterized by low Sr and high Yb contents, reflecting low-pressure magma source conditions with residual plagioclase (i.e. amphibolite facies). These granitoids also exhibit geochemical characteristics typical of arc–type magmatic rocks, with enrichment in large ion lithophile elements (LILEs; e.g. Rb, Ba, and K) and light rare earth elements (LREEs), and depletion in high field strength elements (HFSEs; e.g. Nb, Ta, Ti, and P) and heavy rare earth elements (HREEs), indicating that they were formed in a subduction-related setting. Moreover, magmatic zircons from the studied rocks have relatively homogeneous Hf isotopic compositions (εHf(t) = – 1.4 to +15.1) and corresponding two–stage model (TDM2) ages of 1839–348 Ma, indicating that they were generated by partial melting of Paleoproterozoic–Phanerozoic accreted lower crust, with minor contributions of ancient crustal materials. Their geochemical characteristics and specific lithological assemblage, together with the temporal–spatial distribution of Permian granitic magmatism, indicate that the formation of middle–late Permian granitoids in the northern margin of the NCC was related to southward Paleo–Asian oceanic subduction. Data from this and previous studies lead us to favour a double-sided, early–late Permian subduction model, with the Paleo–Asian Ocean closing after the late Permian.

Multiplex LA-ICP-MS bio-imaging of brain tissue of a parkinsonian mouse model stained with metal-coded affinity-tagged antibodies and coated with indium-spiked commercial inks as internal standards

Year: 2020
Products: NWR213;New Wave;
Authors: Neumann, B;Hösl, S;Schwab, K;Theuring, F;Jakubowski, N;
Journal: J. Neurosci. Methods

Immunohistochemistry techniques represent a powerful tool to detect and quantify disease related proteins. Improvements were accomplished by tagged antibodies using laser ablation and inductively coupled plasma mass spectrometry (LA-ICP-MS). However, these approaches are effected by day-to-variations due to instrumental drift. Brain tissue from line 62, a Parkinson's disease model, and control mice were incubated with four antibodies relevant to the disease and standardized to three house-keeping proteins. In addition, a new standardization approach was developed and the results compared. This new approach consisted of coating specimens with gelatin and printing an indium-doped ink with a commercial ink jet printer. Furthermore, the method was evaluated for different ablation spot sizes with respect to resolution and signal-to-noise ratio. Normalization using house-keeping proteins led to high background signals even at high resolution. Normalization using indium-doped ink improved the signal-to-noise ratio even when small laser spot sizes were used and further improved by overlaying tissue specimen with gelatin. Line 62 mice had more α-Synuclein and gliosis but decreased numbers of neurons, as found by conventional immunohistochemistry. These data are in line with the results obtained by LA-ICP-MS with indium standardization. However, differences between L62 and controls for tyrosine hydroxylase were only detected by LA-ICP-MS. Internal standardisation using indium-doped inks is an effective method to overcome day-to-day variations and instrumental drifts. The new approach results in an increased signal-to-noise ratio and only under these conditions small but significant changes were detected, as seen for tyrosine hydroxylase.

Elemental bioimaging shows mercury and other toxic metals in normal breast tissue and in breast cancers

Year: 2020
Products: NWR193;
Authors: Pamphlett, R;Satgunaseelan, L;Kum Jew, S;Doble, PA;Bishop, DP;
Journal: PLoS ONE

Exposure to toxic metals such as mercury has been proposed to be a risk factor for the development of breast cancer since some metals can promote genetic mutations and epigenetic changes. We sought to find what toxic metals are present in normal breast tissue and in the tumours of women who had mastectomies for invasive ductal breast carcinoma. Formalin-fixed paraffin-embedded blocks from mastectomies for breast carcinoma were examined from 50 women aged 34-69 years. Paraffin blocks selected for elemental analysis were from breast tissue not involved by carcinoma and from the carcinoma itself. Seven micrometer-thick sections were stained with autometallography to demonstrate the presence of mercury, and subjected to laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) to confirm the presence of mercury and to detect other toxic metals. Autometallography-detected mercury was seen in intraductal secretions and some luminal epithelial cells of normal breast lobules in 26 (55%) of the 47 samples where lobules were present, and in 10 (23%) of carcinomas from the 44 samples where carcinoma was present. In eight samples ductal carcinoma in situ was present and one of these contained mercury. LA-ICP-MS confirmed the presence of mercury in samples that stained with autometallography, and detected lead, iron, nickel, aluminium, chromium and cadmium in some samples. Mercury was present in normal breast lobules in more than half of mastectomy samples that contained an invasive carcinoma, and in a smaller proportion of carcinomas and ductal carcinomas in situ. Other toxic metals that may interact synergistically with mercury could be detected in some samples. These findings do not provide direct evidence that toxic metals such as mercury play a role in the pathogenesis of breast cancer, but suggest that future molecular biological investigations on the role of toxic metals in breast cancer are warranted.

Petrogenesis and tectonic setting of Early Paleozoic granites and high-Mg diorites in the Northern Qilian Orogen, China

Year: 2020
Products: UP213;New Wave;
Authors: Pan, F;Dong, Y;Li, X;Huang, B;Zhang, Y;Wang, G;Yu, J;Gao, Y;Zhao, X;
Journal: Journal of Asian Earth Sciences

The Northern Qilian Orogenic Belt (N-QOB) was formed by oceanic subduction and collision between the Alashan and Central Qilian Belt in the Early Paleozoic. New zircon U–Pb ages, Hf isotopic and whole-rock elemental data of the intrusive rocks in the central N-QOB have been conducted to constrain the tectonic evolution of N-QOB. Zircon dating results revealed that the Ladonggou, Suyougou granitic plutons and Xichagou dioritic pluton were emplaced at 505 ± 3 Ma, 471 ± 3 M and 425 ± 3 Ma, respectively. The Ladonggou monzogranite displays depletion of Nb, Ta, Ti, P and negative εHf(t) values (−6.5 to −0.3), and old Hf crustal model ages (1.5–1.9 Ga), suggesting generation from melting of ancient crust above subducted North Qilian oceanic slab. The Suyougou granite possesses geochemistry of I-type granite. The relative enrichment of LILEs, depletion of HFSEs and negative Eu anomalies, as well as prominent Hf isotope heterogeneities and old Hf crustal model ages (2.1–2.5 Ga) suggest a magma source of ancient crust mixed with minor mantle-derived melts in a subduction-related setting. Diorites from the Xichagou plutonare characterized by high Mg# values, enrichments in Cr, Ni, Y, Yb and high Sr/Y ratios, and convincing subduction-related features, suggesting generation from partial melting of subducted sediments mixed with mantle components. Taking all these geochemistry and geochronology together with the regional geology, we interpreted the Ladonggou monzogranite, Suyougou granite and Xichagou diorite were related to the long-term northward subduction of North Qilian oceanic lithosphere during ca. 505 and 425 Ma.

Provenance and tectonic setting of Upper Triassic turbidites in the eastern Tethyan Himalaya: Implications for early-stage evolution of the Neo–Tethys

Year: 2020
Products: New Wave;
Authors: Liu, Y;Dai, J;Wang, C;Li, H;Wang, Q;Zhang, L;
Journal: Earth-Science Reviews

Upper Triassic turbidites in the eastern Tethyan Himalaya preserve archives for early–stage evolution of the Neo–Tethys. However, their provenance and tectonic setting remain controversial. Here we report petrographic, detrital zircon UPb and trace element data of newly discovered sandstones interbedded with layered basalts and whole–rock geochemical data of basalts from the Yumen mélange within Upper Triassic turbidites, and the same types of published data from associated terranes in the eastern Gondwana are compiled for comparison. The interbedded sandstones are dominated by quartz, lithics fragments and plagioclase grains, resembling those of the Langjiexue Group. All samples display similar ranges of detrital zircon UPb ages, with significant age populations at 280–210 Ma, 650–450 Ma and 1200–800 Ma, comparable to those of the Langjiexue Group and coeval turbidites from Western Myanmar and partly from Central Tethyan Himalaya, implying they should share identical provenance. Trace elements of 300–200–Ma–aged zircons indicate they were derived from a continental magmatic arc. Geochemical data from interbedded basalts display typical within–plate–basalt affinity. Synthesized with regional geological setting, the above observations suggest Upper Triassic turbidites from Eastern and part of Central Tethyan Himalaya, and Western Myanmar were deposited in a marine rift basin of Indian passive continental margin with their primary provenance from Lhasa. However, other contemporaneous turbidites from part of Central Tethyan Himalaya and Australia had distinct primary sources from Indian continent and West Papua, respectively, indicating they may have separate deposystems.

Late Cretaceous granitic intrusions and associated deposits in the Yidun Arc of the eastern Tibetan Plateau

Year: 2020
Products: UP213;New Wave;
Authors: Yang, F;Li, W;Jiang, X;Li, C;Wang, Z;Sun, H;Zhou, J;
Journal: Journal of Asian Earth Sciences

The Yidun Arc is an important tectonic unit and polymetallic metallogenic belt in the Sanjiang tectono-magmatic belt, in which many Cretaceous (138–75 Ma) granites and associated polymetallic deposits are distributed along a NW-trending belt. The Queershan, Cuomolong, Rongyicuo, and Genie granitic intrusions and the associated Sn–Pb–Zn–Ag polymetallic deposits are distributed in the Changtai and Xiangcheng Arcs, whereas the Xiuwacu, Relin, Hongshan, and Tongchanggou granitic intrusions and the associated Cu–Mo–W deposits are mainly distributed in the Geza Arc. This study presents new zircon U–Pb–Hf–O isotopic data for the Queershan, Cuomolong, Rongyicuo, Genie, Xiuwacu, and Tongchanggou granitic intrusions, combined with the structural analysis of the Xiuwacu granitic complex, to discuss the differences in the petrogenesis and metallogenesis of these granitic intrusions, as well as the geodynamic processes that controlled the formation of the Late Cretaceous intrusions and related deposits. Hf-O isotopic characteristics indicate that the highly fractionated granites (HFG) in the Changtai and Xiangcheng Arcs were mainly derived from the partial melting of metasedimentary crustal materials with a minor input from mantle components, while the I-type granites (IG) in the Geza Arc were predominantly derived from the partial melting of ancient lower crustal material. The spatial distributions of the different types of deposits in the Yidun Arc were probably controlled by the magma sources. Reduced magmas produced by the partial melting of the sedimentary crust in the Changtai and Xiangcheng Arcs are favorable for W, Sn, Pb, and Zn mineralization, whereas oxidized magmas produced by the partial melting of the lower crust in the Geza Arc are conducive to the enrichment of Cu, Au, and Mo. The geochronological data indicate that the emplacement ages of the Late Cretaceous granites in the Yidun Arc gradually decrease from north to south (ranging from 106 to 73 Ma), reflecting the southward lateral tectonic migration. The structural analysis of the Xiuwacu W–Mo deposit, in combination with previous studies, demonstrated that the Late Cretaceous granites in the Yidun Arc were likely formed in a regional extensional setting, which was probably related to the slab break-off of the Bangong–Nujiang oceanic slab or the subduction of the Yarlung Zangbo oceanic slab.

PET/MRI enables simultaneous in vivo quantification of β-cell mass and function

Year: 2020
Products: NWR213;New Wave;New Wave Research;
Authors: Michelotti, FC;Bowden, G;Küppers, A;Joosten, L;Maczewsky, J;Nischwitz, V;Drews, G;Maurer, A;Gotthardt, M;Schmid, AM;Pichler, BJ;
Journal: Theranostics

Non-invasive imaging of β-cells represents a desirable preclinical and clinical tool to monitor the change of β-cell mass and the loss of function during pre-diabetic stages. Although it is widely accepted that manganese (Mn) ions are actively gated by voltage-dependent calcium channels (VDCC) in response to glucose metabolism, little is known on its specificity in vivo for quantification of islet β-cell function using Mn and magnetic resonance imaging (MRI). On the other hand, glucagon-like-peptide-1 receptor (GLP-1R) represents a validated target for the estimation of β-cell mass using radiolabeled exendin-4 (Ex4) and positron emission tomography (PET). However, a multiparametric imaging workflow revealing β-cell mass and function quantitatively is still missing. Methods: We developed a simultaneous PET/MRI protocol to comprehensively quantify in vivo changes in β-cell mass and function by targeting, respectively, GLP-1R and VDCC coupled with insulin secretion. Differences in the spatial distribution of Mn and radiolabeled Ex4 were monitored overtime in native and transgenic pancreata, characterized by spontaneous pancreatic neuroendocrine tumor development. Follow-up with mass spectrometry imaging (MSI) and autoradiography allowed the ex vivo validation of the specificity of Mn and PET tracer uptake and the detection of endogenous biometals, such as calcium and zinc, throughout the endocrine and exocrine pancreas. Results: Our in vivo data based on a volumetric PET/MRI readout for native pancreata and insulinomas connects uptake of Mn measured at early imaging time points to high non-specific binding by the exocrine tissue, while specific retention was only found 24 h post injection. These results are supported by cross-validation of the spatial distribution of exogenous 55Mn and endogenous 44Ca and 64Zn as well with the specific internalization of the radiolabeled peptide targeting GLP-1R. Conclusion: Simultaneous PET/MR imaging of the pancreas enabled the comprehensive in vivo quantification of β-cell function and mass using Mn and radiolabeled Ex4. Most important, our data revealed that only late time-point measurements reflect the Mn uptake in the islet β-cells, while early time points detect non-specific accumulation of Mn in the exocrine pancreas.

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