Critical minerals resources are widely used in emerging industries, and their mineralization characteristics and metallogenic regularity are of high importance. Skarn deposits are one of the important sources of critical minerals resources. Yaojialing deposit is a typical large skarn zinc polymetallic deposit in Tongling district of the Middle and Lower Yangtze River metallogenic belt. The ore bodies are mainly lenticular and veined occurrence along the proximal skarn zone and structural or lithologic contacts, respectively. We recognize five hydrothermal stages in the deposit: skarn stage, oxide stage, early sulfide stage, late sulfide stage and carbonate stage. The early and late sulfide stages are the main ore-forming stages. In addition to the production of zinc, gold and copper, the deposit also contains critical element resources such as cadmium, cobalt, selenium, and tellurium. Taking the Yaojialing deposit as an example, this paper shows the occurrence and distribution of critical minerals resources in a typical skarn deposit by using scanning electron microscope, TESCAN integrated mineral analyzer (TIMA), and sulfide LA-ICP MS analysis. Although there are no cadmium minerals in Yaojialing deposit, cadmium can incorporated in the sphalerite lattice, and sphalerite in veins has elevated cadmium content (average 5478.78 ppm). Tellurium content in various sulfides is very low, and it does not enter into the sulfide lattice. It mainly forms tellurobismuthite, hessite and tetradymite, which occur in Cu-Zn ore formed in the early sulfide stage, there are 227 tetradymite grains in a single rock section. Selenium occurs as naumannite in vein ore in the distal of the deposit; selenium can also incorporated the lattice of chalcopyrite and sphalerite, and the selenium content is elevated in sphalerite formed in the early sulfide stage (average 226.80 ppm). The cobalt mineral glaucodot is only found in skarn ore; cobalt easily incorporated the lattice of pyrite and sphalerite, and pyrite and sphalerite formed in the early sulfide stage are enriched in cobalt (average 1962.18 ppm). The characteristics of trace elements in pyrite and sphalerite show that temperature is the main factor affecting the distribution of critical minerals resources, high temperature is conducive to the enrichment of cobalt, selenium and tellurium, while low temperature is conducive to the enrichment of cadmium. Cadmium, cobalt, selenium, and tellurium have high content in specific parts of the deposit, which makes them potentially amenable to recovery.
Abstract The Yaojialing deposit is the first large‐scale Zn–Au–Cu polymetallic skarn deposit located in the Shatanjiao ore field of the Tongling area in the Middle–Lower Yangtze belt. It has distinct metallogenic characteristics and is clearly different from the known skarn Cu–Au deposits in the Tongling area and the Middle–Lower Yangtze belt. Previous studies of the Yaojialing deposit have included rock geochemistry, alteration and mineralization characteristics, as well as metallogenesis and metallogenic models. However, there are still numerous problems concerning the coexistence of multiple elements, metallogenetic specialization of the magma and the metallogenic model. In this study, using the latest production exploration work on the deposit, we investigated the Yaojialing deposit including its geological characteristics, petrography, LA–ICP MS zircon U–Pb dating and whole rock geochemistry. Two kinds of magmatic rocks have been distinguished for the first time in the deposit, amongst which the granodiorite porphyry exposed on the surface of the mining area, which is the host rock of the veined lead–zinc ore body, is the wall‐rock intrusion; and the deep concealed quartz monzonite porphyry is the causative intrusion, the distribution of orebodies and wall‐rock alteration characteristics showing regular zoning around the quartz monzonite porphyry. The 206 Pb/ 238 U weighted average age of the granodiorite porphyry is 140.2 ± 1.0 Ma (MSWD = 0.85, n = 13) by LA–ICP MS zircon U–Pb dating, while the quartz monzonite porphyry is 138.9 ± 1.2 Ma (MSWD = 0.60, n = 16), which is consistent with petrographic evidence. The geochemical characteristics show that the quartz monzonite porphyry is a high‐K calc‐alkaline series peraluminous rock. The trace element characteristics show that the quartz monzonite porphyry is enriched in LILE such as K, Rb, Sr, Ba and LREE, yet depleted in HFSE such as Nb, Ta, P and Ti. The Yaojialing deposit shows the mineralization characteristics of proximal skarn and distal skarn, having the common characteristics of ‘multi‐storey’ and ‘Trinity’ metallogenic models.
Abstract The circular RNA (circRNA) family is a group of endogenous non-coding RNAs (ncRNAs) that have critical functions in multiple physiological and pathological processes, including inflammation, cancer, and cardiovascular diseases. However, their roles in regulating innate immune responses remain unclear. Here, we define Cell division cycle 42 (CDC42)−165aa, a protein encoded by circRNA circCDC42, which is overexpressed in Klebsiella pneumoniae (KP)-infected alveolar macrophages. High levels of CDC42-165aa induces the hyperactivation of Pyrin inflammasomes and aggravates alveolar macrophage pyroptosis, while the inhibition of CDC42-165aa reduces lung injury in mice after KP infection by inhibiting Pyrin inflammasome-mediated pyroptosis. Overall, these results demonstrate that CDC42-165aa stimulates Pyrin inflammasome by inhibiting CDC42 GTPase activation and provides a potential clinical target for pathogenic bacterial infection in clinical practice.
The Paleozoic-Mesozoic Youjiang sedimentary basin in SW China is developed on a Lower Paleozoic low-grade metamorphic basement, and contains dozens of Carlin-type gold deposits with a total Au reserve of over 900 metric tonnes (t). Although most of these deposits are hosted in sedimentary rocks, ∼70% of the gold (∼24.5 t) in the Badu deposit is hosted in altered OIB-type dolerite. To date, the ore-fluid source of Carlin-type gold deposits in the basin is highly debated, hampering the formulation of genetic models. Here, for the first time, we present ore-related apatite chemical and Sr isotope compositions from the altered dolerite at Badu to provide new insight into the ore-fluid source of this key gold province. Petrography studies distinguished three apatite generations (Ap1 to Ap3): Pre-ore Ap1 is needle-shaped or fine-grained (<20 μm), and occurs mainly in the unmineralized dolerite; Main-ore Ap2 is euhedral-subhedral coarse-grained (>100 μm) and spatially associated with auriferous pyrite and arsenopyrite in the mineralized dolerite; Late-ore Ap3 is also euhedral-subhedral coarse-grained (>100 μm), and hosted in quartz ± ankerite veins crosscutting the mineralized dolerite. Geochemically, Ap1 contains relatively high Cl (∼0.134 wt%), MnO (∼0.038 wt%), MgO (∼0.155 wt%), and SiO2 (∼0.285 wt%) contents, whereas Ap2 and Ap3 have relatively high SrO contents (∼0.448 and ∼0.45 wt%, respectively). This geochemical difference can be used to distinguish magmatic from hydrothermal apatite at Badu. Ap2 has similar chemistry to Ap3 except for the higher SO3 contents (up to ∼0.318 wt%), and they both have similarly higher 87Sr/86Sr ratios (0.709489–0.711787) than those of the unmineralized dolerite (0.706295–0.706323) and the sedimentary ore host in the basin, but similar to the Lower Cambrian basement rocks (0.70909–0.82733). This similarity indicates that the ore-forming fluids were dominantly sourced from the basinal basement or from deep magmatic fluids with radiogenic Sr addition from the basement rocks. The ore-forming fluids may also have leached MREEs from the sulfate-rich basement rocks, leading to the observed MREE enrichments in Ap2 and Ap3. Our study highlights that the basement material contribution is critical for the Carlin-type gold mineralization in the Youjiang basin.
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