Petrogenesis, W metallogenic and tectonic implications of granitic intrusions in the southern Great Xing’an Range W belt, NE China: insights from the Narenwula Complex

Abstract

Extensive magmatism in NE China, eastern Central Asian Orogenic Belt, has produced multi-stage granitic plutons and accompanying W mineralization. The Narenwula complex in the southwestern Great Xing’an Range provides important insights into the petrogenesis, geodynamic processes and relationship with W mineralization. The complex comprises granodiorites, monzogranites and granite porphyry. Mafic microgranular enclaves are common in the granodiorites, and have similar zircon U–Pb ages as their host rocks (258.5–253.9 Ma), whereas the W-bearing granitoids yield emplacement ages of 149.8–148.1 Ma. Permian granodiorites are I-type granites that are enriched in large-ion lithophile elements and light rare earth elements, and depleted in high field strength elements and heavy rare earth elements. Both the mafic microgranular enclaves and granodiorites have nearly identical zircon Hf isotopic compositions. The results suggest that the mafic microgranular enclaves and granodiorites formed by the mixing of mafic and felsic magmas. W-bearing granitoids are highly fractionated A-type granites, enriched in Rb, Th, U and Pb, and depleted in Ba, Sr, P, Ti and Eu. They have higher W concentrations and Rb/Sr ratios, and lower Nb/Ta, Zr/Hf and K/Rb ratios than the W-barren granodiorites. These data and negative ϵHf(t) values (–6.0 to –2.1) suggest that they were derived from the partial melting of ancient lower crust and subsequently underwent extreme fractional crystallization. Based on the regional geology, we propose that the granodiorites were generated in a volcanic arc setting related to the subduction of the Palaeo-Asian Ocean, whereas the W-bearing granitoids and associated deposits formed in a post-orogenic extensional setting controlled by the Mongol–Okhotsk Ocean and Palaeo-Pacific Ocean tectonic regimes.

Formation and evolution of multistage hydrothermal fluids in the Baishitouwa quartz–wolframite vein‐type deposit in the southern Great Xing'an Range tungsten belt, NE China: Constraints from individual fluid inclusion LA‐ICP‐MS analysis

“…Four episodes of granitic magmatism are recognized, including Late Permian, Triassic, Early–Middle Jurassic, and Late Jurassic (Figure 2). The widespread Late Permian granodiorites and quartz diorites intrude into the Proterozoic–Early Palaeozoic strata with zircon U–Pb ages of 254–259 Ma (Xie, Zeng, Yang, et al, 2022). A Triassic granitic pluton is locally exposed in the southwestern part of the region, which emplaced at ~233 Ma (Xie et al., 2022a).…”

“…The rock types mainly include fine‐grained granite and minor biotite granite (IMBGMR, 1991). The granitoids from the Late Jurassic period are common in the central and western parts, which are composed of monzogranite (~148 Ma) and granite porphyry (~150 Ma) (Xie, Zeng, Yang, et al, 2022) (Figure 2).…”

Ore Genesis of the Baishitouwa Quartz–Wolframite Vein-Type Deposit in the Southern Great Xing’an Range W Belt, NE China: Constraints from Wolframite In-Situ Geochronology and Geochemistry Analyses

“…From the Late Triassic onward, the tectonic framework of the XMOB was dominated by the closure of the Mongol-Okhotsk Ocean in the northwest, and subduction of the Paleo-Pacific Ocean in the east [38,[73][74][75][76][77][78]. During and after the longlived accretionary orogenic amalgamation and collision, the XMOB experienced a series of orogenic activity, backarc basin formation, and extensive magmatism and mineralization [4,5,[8][9][10]30,38,69,[78][79][80].…”

“…Three episodes of W mineralization are identified, including Triassic (240-250 Ma), Early-Middle Jurassic (170-200 Ma), and Late Jurassic-Early Cretaceous (125-160 Ma) [5]. Previous studies mainly focused on the Jurassic and Early Cretaceous W mineralization [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. In contrast, only a limited amount of research has been conducted on the Triassic deposits, especially the quartz-wolframite vein-type deposits [31,32], which hinders our understanding of regional W mineralization.…”

“…In contrast, only a limited amount of research has been conducted on the Triassic deposits, especially the quartz-wolframite vein-type deposits [31,32], which hinders our understanding of regional W mineralization. In addition, previous studies on the ore genesis of quartz-wolframite vein-type deposits in this region were focused mainly on the geological features [33,34], geochronology of related granites [15,19,30,35], fluid inclusions [24,25,36], and isotopic analyses [13,18,21,23,26,29]. In contrast, wolframite, as the most important tungsten-bearing mineral in quartz-wolframite vein-type deposits, has not attracted the attention of researchers for many years, thus hindering our understanding of the detailed ore-forming process of quartz-wolframite vein-type deposits.…”