Jingbin Wang

Composition of Titanomagnetite and Microstructure of Banded Type Ore in Weiya Fe-V-Ti oxide Deposits and its Implication on Metallogenesis

Weiya Fe-Ti-V oxide deposit is the biggest one in North Xinjiang, and lots of work on petrology, mineralogy, chronology and isotope geochemistry have been done by previous workers. However, the formation mechanism of massive ore type and banded type ore is not clear. Banded type Fe-Ti-V oxide ore not only is an important ore type in Weiya deposit (Wang et al., 2005, 2008), but also could give some clues in understanding the petrogenesis and metallogenesis of Fe-Ti-V oxide deposits. Therefore, systematic observation was carried on to explore the petrogenesis and metallogenesis process. At the same time, chemical composition of titanomagnetite in four types of rocks including two types of host rocks and two types of ore were analyzed to discuss the origin of FeTi-V oxide.

Age and geochemistry of the Carboniferous-Permian magmatism and Fe-Ti-V oxide metallogeny in the Eastern Tianshan Orogen, NW China: evidence from the Yaxi mafic-ultramafic complex

ABSTRACT The Eastern Tianshan Orogen (Xinjiang, NW China) in the Central Asian Orogenic Belt (CAOB) is featured by its many Carboniferous-Triassic mafic-ultramafic intrusions and associated magmatic Fe-Ti-V oxide mineralization. In this study, we present the first systematic data comparison on the age and whole-rock geochemistry of the ore-forming mafic-ultramafic complexes at Yaxi, Niumaoquan, Xiangshanxi, and Weiya. Our new age dating on the Yaxi complex indicates that the mineralized gabbro (zircon SHRIMP U-Pb dated 297.3 ± 4.9 Ma) formed in the latest Carboniferous-Early Permian, similar to the diorite (LA-ICP-MS zircon U-Pb dated 308.3 ± 8.6 Ma) and granodiorite (LA-ICP-MS zircon U-Pb dated 304.9 ± 1.7 Ma). The Yaxi complex is the oldest late Palaeozoic mafic-ultramafic intrusion reported so far in the Eastern Tianshan. The mineralized gabbro at Yaxi contains higher average Fe2O3T (20.83 wt.%), TiO2 (5.91 wt.%), and V (523 ppm) contents than its ore-barren counterpart (7.45 wt.%, 0.99 wt.%, and 133 ppm, respectively). These Eastern Tianshan mafic rocks are mildly large ion lithophile element (LILE) enriched and high field-strength element (HFSE) depleted, and with LREE/HREE enrichment (Yaxi: (La/Yb)N = 2.7 ~ 5.37) and subtle positive Eu anomalies (Yaxi: Eu/Eu* = 0.94 to 3.31). This suggests that the Eastern Tianshan mafic-ultramafic magmas were likely derived from an arc/subduction-modified magma source. The E-W trending crustal-scale faults (e.g. the Aqikkuduk fault) may have acted as magma conduits and controlled the magma emplacement. The spatial-temporal distribution of the Eastern Tianshan Fe-Ti-V ore-forming mafic-ultramafic complexes and their petrologic and geochemical features suggest that the latest Carboniferous-Early Permian magmatic phase was likely emplaced in a collision-related compression setting following the Junggar Ocean closure, whereas the late Early Permian phase may have been related to a post-collisional orogenic setting. Graphical Abstract

Petrogenesis and Metallogenesis of the Niumaoquan Gabbroic Intrusion Associated with Fe-Ti Oxide Ores in the Eastern Tianshan, NW China

The Niumaoquan layered gabbroic intrusion is in the southern margin of the Central Asian Orogenic Belt in North Xinjiang, China, and hosts a Fe-Ti oxide deposit in its evolved gabbroic phases. In this paper, we report zircon U-Pb age, Sr-Nd-Hf isotopes, plagioclase chemistry, and whole-rock geochemistry of the Niumaoquan layered gabbroic intrusion. Zircon grains separated from an anorthosite sample analyzed by laser ablation inductively coupled plasma mass spectrometry yielded a concordia age of 314.7±0.74 Ma, indicating that the Niumaoquan ore-bearing gabbroic intrusion was emplaced during the Late Carboniferous. The olivine gabbro texture and plagioclase chemistry suggest that plagioclase was an early crystallized silicate phase that crystallized prior to olivine. Fractional crystallization and accumulation of plagioclase significantly controlled the evolution of the Niumaoquan gabbroic intrusion and contributed to the formation of anorthosite layers, causing metallogenic elements to become enriched in the residual melt. The Niumaoquan gabbroic intrusion is characterized by the enrichment of large ion lithophile elements and depletion of high field strength elements, positive zircon εHf(t) values (+2.1 to +12.2), positive εNd(t) values (+3.3 to +5.2), and low initial Sr/Sr ratios (0.7039 to 0.7047), suggesting that the parental magma was produced by interactions between metasomatized lithospheric mantle and depleted asthenospheric melts at an early post-collision stage. The Fe-Ti oxide mineralization of the Niumaoquan intrusion benefited from interactions between depleted asthenospheric melts and lithospheric mantle, and fractional crystallization of abundant plagioclase and

Features and significance of the Yudai porphyry copper deposit in the Kalatag district, eastern Tianshan, NW China

The eastern Tianshan region covers around 60000 km in area and is located in the eastern part of Xinjiang. The district contains various types mineral commodities including Cu, Ni, Au, Fe, Pb and Zn (Wang et al., 2006). The Dannanhu belt in eastern part of the area is interpreted as a volcanic arc and forms an important mineralized zone bordered by the Turpan-Hami Basin to the north and Kanggur back-arc basin to the south. Several porphyry deposits have been discovered in eastern Tianshan region, including Tuwu-Yandong, Linlong, Chihu, Yuhai and Sanchakou deposits (Wang and Zhang, 2016). Numerous studies have been completed on late Palaeozoic magmatic rocks in the district, but less attention has been paid to early Palaeozoic igneous rocks. Several early Paleozoic Cu-polymetallic deposits have discovered in the Kalatag district of eastern Tianshan region within the last ten years, including the South Meiling VMS deposit, Hongshi hydrothermal vein deposit and Yudai porphyry Cu deposit (Deng et al., 2016a, b). Yudai was discovered in 2011, but the paragenesis of the deposit has been poorly understood due to the lack of detail studies. This paper is mainly describe the above issues. *