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The Dunde iron–zinc deposit (185 Mt at 35% Fe), located in the Tianshan orogenic belt, Xinjiang, northwest China, is hosted in late Carboniferous volcanic–volcaniclastic rocks characterized by prograde skarn formation and retrograde alteration, but the ore lacks any clear spatial link with intrusive rocks. Four stages of skarn formation and ore development can be recognized: (1) a prograde skarn stage that formed grossularitic garnet (Gr39–80; Ad15–58) and diposidic pyroxene (Di63–97); (2) a retrograde skarn stage dominated by the formation of magnetite with minor epidote, ferropargasite, apatite, hematite, and trace amounts of titanite and spinel; (3) a sulfide stage dominated by the formation of arsenide (loellingite and arsenopyrite) and sulfide minerals (sphalerite, pyrrhotite, pyrite, chalcopyrite, and minor galena), calcite, and traces of quartz; and (4) a chlorite–calcite stage mainly characterized by the formation of chlorite, calcite, and traces of sericite. Exsolution of droplet-like and patchy chalcopyrite is developed within sphalerite of the sulfide stage, indicating an exsolution temperature of 350–400 °C. As such, the crystallization temperature of early stage magnetite may have been > 400 °C. Abundant fluid inclusions occur in calcite, which include daughter-mineral-bearing H2O, H2O, and pure H2O inclusions. The H2O inclusions have a wide range of homogenization temperatures from 147 °C to 367 °C with salinities of 2.4–23.4 wt.% NaCl equivalent. The daughter-mineral-bearing H2O inclusions have homogenization temperatures from 172 °C to 347 °C with salinities of 31.9–33.0 wt.% NaCl equivalent. Using the chlorite geothermometer, the temperature of chlorite formation is constrained to be between 152 °C and 222 °C (average = 194 °C). Sulfur isotope compositions of pyrrhotite, sphalerite, pyrite, and loellingite have a narrow range of δ34S values from 3.8‰ to 8.1‰ (average δ34S = 6.8‰), suggesting that the sulfur was magmatic-derived. Zircon LA–ICP-MS U–Pb dating of wall rock dacite yields a weighted mean 206Pb/238U age of 316.0 ± 1.7 Ma. Combined with previous dating results of magnetite-mineralized diorite stocks, diorite dikes, and garnet skarn, it can be inferred that the Dunde iron–zinc deposit formed in the late Carboniferous after 316 Ma and is genetically related to deep dioritic intrusions. During the late Carboniferous, the tectonic setting of this region changed from subduction–collision to extension, accompanied by mantle-derived magma underplating in deep. After the formation of the iron–zinc ore deposit, the Dunde district was intruded by an early Permian K-feldspar granite that yields a zircon LA–ICP-MS U–Pb age of 295.75 ± 0.71 Ma.

Several large syngenetic volcanogenic iron ore deposits including the Chagangnuoer Fe–Cu, the Zhibo Fe and the Beizhan Fe deposits occur in the Awulale Fe–Cu Metallogenetic Belt (AMB) which is located in the southeastern corner of the Yili block in the Western Tianshan Mountains (NW-China). In the present study, we report geochronological and geochemical data for granitoid rocks associated with the Zhibo iron ore deposit in order to constrain the age of the stratiform Fe mineralization and tectonic setting of this deposit. Laser ablation-ICPMS (LA-ICPMS) U–Pb zircon ages of 318.9 ± 1.5 Ma and 304.1 ± 1.8 Ma were obtained for a diorite and a granite pluton, respectively, both of which intruded the volcanic–volcaniclastic rocks of the Early Carboniferous Dahalajunshan Formation. Additional LA-ICPMS U–Pb zircon ages of 320.3 ± 2.5 Ma and 294.5 ± 1.6 Ma were obtained for two crosscutting granite dikes, respectively. The ca. 319 Ma diorite has a high-potassium calc-alkaline, weakly peraluminous composition and is characterized by large ion lithophile element (LILE) and light rare earth element (LREE) enrichment and flat heavy rare earth element (HREE) patterns. It further shows distinct negative anomalies of Nb, Ta and Ti. In contrast, the ca. 304 Ma granite classifies as A2 type granite and is characterized by an enrichment of LILE and LREE, flat HREEs and distinct negative anomalies of Ba, Nb, Ta and Ti. The ca. 320 Ma granite dike has a low-potassium and weakly peraluminous composition and is characterized by LILE and LREE enrichment and a distinct depletion of Nb, Ta, Ti and HREE. The ca. 295 Ma granite displays a high-potassium calc-alkaline and weakly peraluminous composition and is characterized by a slight enrichment of LILE and LREE, flat HREEs and a distinct depletion of Nb, Ta and Ti. The data presented here in conjunction with previously published data suggest a submarine, syngenetic volcanogenic mineralization age of ca. 320 Ma for the Zhibo iron ore deposit. The Zhibo and other submarine volcanogenic iron ore deposits of the AMB are inferred to have formed in a continental arc-setting related to subduction tectonics. Furthermore, post-collisional granitic magmatism from 304 to 295 Ma was superimposed on the entire AMB.

NiOx thin films were grown on quartz-glass substrates by two-step process: oxidation of metal Ni thin film which was obtained by vacuum evaporation method. The structural, optical and electrical properties of NiOx thin film were investigated by X-ray diffraction, absorption spectra and Hall measurement, respectively. The oxidation temperature could influence the structural, electrical and optical properties of NiOx thin film. At lower oxidation temperature (623 K), the oxidation process was not finished completely. With the increase of oxidation temperature, Ni thin films were totally oxidized into p-type NiO thin films and the optical absorption edge became steeper. Furthermore, the conductivity and carrier concentration of p-type NiO thin film decreased with the increase of oxidation temperature.