Early Permian A‐type Granites in the Zhangdaqi Area, Inner Mongolia, China and Their Tectonic Implications

Abstract

There is a controversy regarding the amalgamation of Xing'an and Songnen Blocks along the Hegenshan-Heihe Suture (HHS) in the eastern Central Asian Orogenic Belt (CAOB). To solve this problem, we performed detailed study on the granites from the Zhangdaqi area, adjacent to the north of the HHS in the northern part of the Great Xing'an Range, NE China. Geochemically, the granites in the study area are metaluminous-weak peraluminous and high-K calc-alkaline series. Trace elements of the granites show that LREEs are relatively enriched, while HREEs are relatively deficient and obvious REE fractionation. The granites are characterized by obvious negative Eu anomalies, meanwhile, they are relatively enriched in Rb, K, Th and depleted in Ba, Nb, Sr, P, Ti. All the geochemical features suggest that the granites in the Zhangdaqi area are aluminum A-type granites. The zircon LA-ICP-MS U-Pb ages of these granites are 294-298 Ma, indicating that they formed in the Early Permian. These granites also have positive ε Hf (t) values (8.4-14.2) and a relatively young two-stage model age between 449 Ma and 977 Ma, implying that the magma was derived from the re-melting of the Early Paleozoic-Neoproterozoic juvenile crust. Combined with geochemical characteristics (Nb/Ta ratios of 9.0-22.2, and Zr/Hf ratios of 52.3-152.0), we believe that the magmatic source area is a mixture of partial melting of the lower crust and depleted mantle. A-type granites and bimodal volcanic rocks along the Hegenshan-Heihe Suture formed during the Late Carboniferous-Early Permian, indicating that the HHS between Xing'an and Songnen Blocks closed in the late Early-Carboniferous. Subsequently, the Zhangdaqi area was in a post-orogenic extensional environment from Late Carboniferous to Early Permian and resulted in the formation of the A-type granites.

Hydrogeochemical characteristics, driving factors, and health risk assessment of karst groundwater in Southwest Hubei Province, China

“…Gibbs diagrams can be used to disclose the composition and variation trend of chemical ions in groundwater and determine whether their sources are controlled by water–rock interactions, evaporation, or precipitation (Chu et al, 2023; Gao et al, 2023; Yang et al, 2023; Zhang, Diao, et al, 2021). According to the obtained results, the groundwater samples collected from the study area are located in the central part of the Gibbs diagrams (Figure 4), indicating that water–rock interaction was the major factor controlling the hydrochemical characteristics of the karst groundwater.…”

Late Paleozoic Tectonic Evolution of the Paleo‐Asian Ocean in the Northern Alxa Block (NW China)

“…Compiled zircon Hf and whole‐rock Nd isotopic compositions from Carboniferous to early Triassic plutons and volcanic rocks in the northern margin of the Alxa Block and adjacent regions. (a) Zircon Hf isotopic data are from Shi, Wang, et al (2014) and Shi, Zhang, et al (2014) for the Zongnaishan‐Shalazhashan Zone (ZSZ); Shi et al (2019), Wang et al (2019), and Zhang et al (2018, 2019) for the Central Asian Orogenic Belt (CAOB); Dan et al (2015), Dan, Li, Wang, Tang, and Liu (2014), Hu et al (2015), Liu et al (2017a, b), Liu, Zhao, et al (2016), Peng et al (2013), Pi et al (2010), Zheng, Li, et al (2019), and Zheng, Zhang, and Xiao (2019) for the Nuoergong‐Langshan Zone (NLZ); and Bai et al (2013), Ma et al (2013), Zhang et al (2007), and Zhang, Zhao, Kröner, et al (2009) for the north margin of North China Craton (NMNCC). (b) Whole‐rock Nd isotopic compositions in the ZSZ are from Gan et al (2018), Shi et al (2018), and Zhang, Wu, Feng, et al (2013); the CAOB are from Miao et al (2008), Zhang et al (2008), and Zhang et al (2018); the NLZ are from Dan et al (2015), Dan, Li, Wang, Tang, and Liu (2014), Liu et al (2017a), and Zheng, Li, et al (2019); and the NMNCC are from Ji et al (2018), Ma et al (2013), Zhang, Zhao, Liu, and Hu (2016), Zhang, Zhao, Kröner, et al (2009), and Zhang, Zhao, Song, et al (2009).…”

Tectonic Transition from Passive to Active Continental Margin of Nenjiang Ocean: Insight from the Middle Devonian-Early Carboniferous Granitic Rocks in Northern Great Xing’an Range, NE China

“…Zircon LA-ICP-MS U-Pb dating and Lu-Hf isotope analysis were completed in the Isotopic Laboratory, Tianjin Institute of Geology and Mineral Resources, Tianjin, China. The main instrument parameters, experimental procedures, and data analysis methods are shown in [51].…”