Geochemical study of Cretaceous magmatic rocks in Chuzhou region, low Yangtze River metallogenic belt: implications for petrogenesis and Cu–Au mineralization

<p>The low Yangtze River metallogenic belt (LYRMB) is one of the most important poly-metal deposit belts in China. The Chuxian, Machang and Shangyaopu intrusions in the LYRMB are intermediate rock series, mainly composed of monzonite and quartz monzonite. In this study, bulk rock major and trace elements, zircon U–Pb dating and Hf isotope were analysed. Five ages have been obtained as (1) Chuxian, 121.8 ± 1.9 and 124.0 ± 1.4 Ma, respectively, (2) Machang intrusion, 123.1 ± 2.0 Ma and (3) Shangyaopu, 126.6 ± 1.8 and 123.4 ± 1.9 Ma, indicating that the regional igneous activity was in Early Cretaceous, being consistent with the massive Yanshanian magmatic events in eastern China. These three intrusions are identified as a high-Mg adakite, most of them showing geochemical features of high Si, high Na and low Sr, which can be interpreted as partial melting of subducted oceanic crust. High Mg# characteristics indicate the magmas reacted with the mantle. The negative zircon <i>ε</i>_Hf values of these adakites suggest that the magmas have assimilation of old crustal material, e.g. Archaean continental crust, the basement of the south Tancheng–Lujiang (Tan–Lu) fault. Biotite Ti temperature result (about 700°C) shows that intrusive magma has a relatively low temperature. Petrogenesis and regional Cu–Au mineralization mechanism may be explained by Pacific plate subduction during about 125–180 million years subducted to southwest towards the LYRMB. Magmas formed by partial melting of subducted oceanic crust have systemically high Cu–Au contents, which are conducive to corresponding mineralization.</p

Recycling of palaeo-Pacific subducted oceanic crust related to a Fe–Cu–Au mineralization in the Xu-Huai region of North Anhui-Jiangsu, East China: Geochronological and geochemical constraints

<p>In this study, Early Cretaceous skarn deposits and genesis of their host diorite/monzodiorite porphyry in the Xuzhou-Huaibei (Xu-Huai) region, northern Anhui-Jiangsu have been discussed by detailed geochemical work. In-situ zircon U–Pb dating of the diorites related to Fe–Cu–Au deposits shows that they were formed between 131.4 ± 1.5 Ma and 130.8 ± 1.8 Ma. Geochemical data indicate a depletion of high field strength elements (HFSE) in the diorite porphyry with similarity to that of arc-related igneous rocks. The diorite porphyry was probably derived from typical arc magmas related to continental margin subduction characterized by light rare earth elements (LREEs) enrichment and HFSE depletion. REEs compositions of apatite in the diorite porphyry indicate that the dioritic magma was produced from the metasomatized subcontinental mantle by slab-derived fluids. The magma was proven to be a high oxygen fugacity; thus, it was particularly conducive to the precipitation of Fe, Cu, Au and other ore-forming elements. The δ³⁴S values of pyrite and chalcopyrite of Fe–Cu–Au ores range from −0.2‰ to 2.8‰, indicating that the sulphur in the ore was probably derived from deep-seated magmas. Integrated with geochronological and geochemical analyses, we suggest that the Early Cretaceous igneous suites associated with Fe–Cu–Au deposits in the Xu-Huai region are related to recycling subduction of Pacific oceanic crust.</p

Synergistic DFT-guided design and microfluidic synthesis of high-performance ion-imprinted biosorbents for selective heavy metal removal

International water security has become unprecedentedly complicated, therefore, effective and selective removal of hazardous materials, especially toxic heavy metal ions, are significant for effluent purification. In this regard, ion-imprinted polymers with special recognition cavities have received much attention. However, configuration screening and performance optimization of functional materials by trial-and-error design method is undoubtedly time- and money-consuming. In this study, high-performance ion-imprinted chitosan microspheres (ICSMs) were successfully designed via density functional theory (DFT) calculation and synthesized via facile microfluidic technology. As-synthesized ICSMs exhibited highly uniform morphology (Dav = 420.6 µm, CV = 3.6%) and ultra-high adsorption capacity (qmax = 107.12 mg g−1). The adsorption isotherm was best fitted to the Langmuir model while the kinetic data followed the pseudo-second order model, indicating a dominant role of chemisorptions. Also, ICSMs displayed satisfactory stability and reusability (95.34 mg g−1, after 5 cycles). Moreover, the selective adsorption mechanism was quantitative revealed by electronegativity, electrophilicity index, adsorption energy (Ea) and bond length. This study is expected to lay a foundation for high-performance biosorbents design and synthesis for future water remediation

Genesis of Early Cretaceous porphyrite-type iron deposits and related sub-volcanic rocks in the Ningwu Volcanic Basin, Middle-Lower Yangtze Metallogenic Belt, Southeast China

<p>The Ningwu Volcanic Basin (NVB), located in the Lower Yangtze Metallogenic Belt, is characterized by the widespread occurrence of porphyritic iron-ore deposits. These deposits are clustered in three areas within the basin: the northern, central, and southern districts. Our study shows that the differences are existed in geochemistry of the rocks and the mineralization of the deposits among these three districts. Though results of Sr–Nd isotopes indicate that the parental magma of the sub-volcanic rocks in NVB were derived from EMI and EMII, however, the sub-volcanic rocks from the northern and southern districts have higher ε_Nd(<i>t</i>) values (<i>t</i> = 130 Ma) and lower initial ⁸⁷Sr/⁸⁶Sr ratios (<i>t</i> = 130 Ma) than those from middle district. The rocks from northern and southern districts are similar to EMI in geochemistry; in contrast, rocks from the middle district are close to EMII. Meanwhile, the deposits from different districts show some differences in mineralization. The magnetites from the northern ore deposits are rich in Cu, Mo, Zn, and Mg and poor in Ca, Al, and Ti, which probably indicates that the magnetites from the northern ore deposits closer to hydrothermal genesis than to magmatic genesis, but the magnetites from the centre are closer to both magmatic and hydrothermal geneses. Based on the fact that a part of the sub-volcanic rocks is closer to EMI and another part to EMII in geochemistry, we suggested that the incorporation of the lower and upper crustal materials into the source regions of the sub-volcanic rocks has taken place by different manner and processes. Integrated with analysis of the tectonic evolution of NVB, we come to the conclusion that the sub-volcanic rocks have recorded the geochemical imprints of the subduction of Yangtze block towards North China block during Indosinian Period and the delamination of the lower crust of Yangtze block during Yanshanian Period.</p

Constructing Hollow Multishelled Microreactors with a Nanoconfined Microenvironment for Ofloxacin Degradation through Peroxymonosulfate Activation: Evolution of High-Valence Cobalt-Oxo Species

This study constructed hollow multishelled microreactors with a nanoconfined microenvironment for degrading ofloxacin (OFX) through peroxymonosulfate (PMS) activation in Fenton-like advanced oxidation processes (AOPs), resulting in adequate contaminant mineralization. Among the microreactors, a triple-shelled Co-based hollow microsphere (TS-Co/HM) exhibited optimal performance; its OFX degradation rate was 0.598 min–1, which was higher than that of Co3O4 nanoparticles by 8.97-fold. The structural tuning of Co/HM promoted the formation of oxygen vacancies (VO), which then facilitated the evolution of high-valence cobalt-oxo (Co(IV)O) and shifted the entire t2g orbital of the Co atom upward, promoting catalytic reactions. Co(IV)O was identified using a phenylmethyl sulfoxide (PMSO) probe and in situ Raman spectroscopy, and theoretical calculations were conducted to identify the lower energy barrier for Co(IV)O formation on the defect-rich catalyst. Furthermore, the TS-Co/HM catalyst exhibited remarkable stability in inorganic (Cl–, H2PO4–, and NO3–), organic (humic acid), real water samples (tap water, river water, and hospital water), and in a continuous flow system in a microreactor. The nanoconfined microenvironment could enrich reactants in the catalyst cavities, prolong the residence time of molecules, and increase the utilization efficiency of Co(IV)O. This work describes an activation process involving Co(IV)O for organic contaminants elimination. Our results may encourage the use of multishelled structures and inform the design of nanoconfined catalysts in AOPs

Formation and geodynamic implication of the Early Yanshanian granites associated with W–Sn mineralization in the Nanling range, South China: an overview

<p>The Nanling range (Nanling) is characterized by intense and widespread Mesozoic magmatism related large-scale W–Sn mineralization. A summary of geochemistry, geochronology, and petrogenesis for the W–Sn-bearing granites has been carried out in this study. A series of rock- and ore-forming ages in Nanling indicate that the W–Sn mineralization is closely related to the Early Yanshanian granitic magmatism both in temporal and spatial dimensions (165–150 Ma). Geochemical features show that both of the W- and Sn-bearing granites, which mainly belong to highly fractionated I-type granites with a few A-type granites, are characterized by high contents of SiO₂, Al₂O₃, Na₂O, and K₂O; enrichment in Rb, Th, U, Zr, Hf, and REE; depletion in Sr, Ba, P, and Ti; and high ratios of A/CNK. Furthermore, the different Sr–Nd–Hf isotopic compositions indicate that they are mainly originated from the partial melting of the Precambrian basement rocks of the Cathaysia Block at low oxygen fugacity, and the estimated temperatures for the tungsten-bearing and tin-bearing granites are ca. 700°C and ca. 800°C, respectively. The model of the mantle–crust interaction exhibits that different percentages of mantle-derived magma were likely involved in the generation of the tin-bearing granites and tungsten-bearing granites. In combination with previous studies, we propose that these granites in Nanling were emplaced in an extensional setting, as a response to the break-off and roll-back of the subducted Palaeo-Pacific Plate during 175–150 Ma.</p

Study of late-Mesozoic magmatic rocks and their related copper-gold-polymetallic deposits in the Guichi ore-cluster district, Lower Yangtze River Metallogenic Belt, East China

<p>The Guichi ore-cluster district in the Lower Yangtze River Metallogenic Belt hosts extensive Cu–Au–Mo polymetallic deposits including the Tongshan Cu–Mo, Paodaoling Au, Matou Cu–Mo, Anzishan Cu–Mo, Guilinzheng Mo and Zhaceqiao Au deposits, mostly associated with the late Mesozoic magmatic rocks, which has been drawn to attention of study and exploration. However, the metallogenic relationship between magmatic rocks and the Cu–Au-polymetallic deposits is not well constrained. In this study, we report new zircon U–Pb ages, Hf isotopic, and geochemical data for the ore-bearing intrusions of Guichi region. LA-ICP-MS U–Pb ages for the Anzishan quartz diorite porphyrite is 143.9 ± 1.0 Ma. Integrated with previous geochronological data, these late Mesozoic magmatic rocks can be subdivided into two stages of magmatic activities. The first stage (150–132 Ma) is characterized by high-K calc-alkaline intrusions closely associated with Cu–Au polymetallic ore deposits. Whereas, the second stage (130–125 Ma) produced granites and syenites and is mainly characterized by shoshonite series that are related to Mo–Cu mineralization. The first stage of magmatic rocks is considered to be formed by partial melting of subducted Palaeo-Pacific Plate, assimilated with Yangtze lower crust and remelting Meso-Neoproterozoic crust/sediments. The second stage of magmatism is originated from partial melting of Mesoproterozoic-Neoproterozoic crust, mixed with juvenile crustal materials. The depression cross to the uplift zone of the Jiangnan Ancient Continent forms a gradual transition relation, and the hydrothermal mineralization composite with two stages have certain characteristics along the regional fault (Gaotan Fault). Guichi region results from two episodes of magmatism probably related to tectonic transition from subduction of Palaeo-Pacific Plate to back-arc extensional setting between 150 and 125 Ma, which lead to the Mesozoic large-scale polymetallic mineralization events in southeast China.</p