Mineralization Epochs of Granitic Rare-Metal Pegmatite Deposits in the Songpan–Ganzê Orogenic Belt and Their Implications for Orogeny

Abstract

Granitic pegmatite deposits, which are usually products of orogenic processes during plate convergence, can be used to demonstrate regional tectonic evolution processes. In the eastern Tibetan Plateau in China, the Jiajika, Dahongliutan, Xuebaoding, Zhawulong, and Ke’eryin rare metal pegmatite deposits are located in the southern, western, northern, midwestern, and central areas of the Songpan–Ganzê orogenic belt, respectively. In this study, we dated two muscovite Ar–Ar ages of 189.4 ± 1.1 Ma and 187.0 ± 1.1 Ma from spodumene pegmatites of the Dahongliutan deposit. We also dated one zircon U-Pb age of 211.6 ± 5.2 Ma from muscovite granite, two muscovite Ar–Ar ages of 179.6 ± 1.0 Ma and 174.3 ± 0.9 Ma, and one columbite–tantalite U-Pb age of 204.5 ± 1.8 Ma from spodumene pegmatites of the Zhawulong deposit. In addition, we dated one muscovite Ar–Ar age of 159.0 ± 1.4 Ma from spodumene pegmatite of the Ke’eryin deposit. Combining these ages and previous studies in chronology, we concluded that the granitic magma in the Jiajika, Xuebaoding, Dahongliutan, Zhawulong, and Ke’eryin deposits intruded into Triassic metaturbidites at approximately 223, 221, 220–217, 212, and 207–205 Ma, respectively, and that the crystallization of the corresponding pegmatite ceased at approximately 199–196, 195–190, 189–187, 180–174, and 159 Ma, respectively. In this study, we demonstrated that the peak in magmatic activity and the final crystallization age of the pegmatite lagged behind one another from the outer areas of the orogeny belt to the inner areas. The pegmatite–parented granitic magmas were sourced from Triassic metaturbidites that were melted by shear heating along the large-scale decollement resulting from Indosinian collisions along the North China block, Qiangtang–Changdu block, and Yangtze block. As a result, the above temporal and spatial regularities indicated that the tectonic–thermal stress resulting from the collisions of three blocks was transferred from the outer areas of the orogenic belt to the inner areas. A large amount of heat and a slow cooling rate at the convergent center of thermal stress in two directions will lead to crystallization and differentiation of magma in the Songpan–Ganzê orogenic belt, forming additional rare metal deposits.

Spatial‐Temporal Distribution, Geological Characteristics and Ore‐Formation Controlling Factors of Major Types of Rare Metal Mineral Deposits in China

“…38 in Fig. 1), and 0.51 Mt in the Keéryin ore field (Wang et al, 2005(Wang et al, , 2016Fu et al, 2017;Li et al, 2019;Fei et al, 2020). Another significant discovery in the KSGOB is the Bailongshan-Dahongliutan pegmatite-type rare metal deposits in the West Kunlun orogenic belt, Xinjiang (Yan et al, 2018;Wang et al, 2020), where 14 rare metal deposits along the 600-kmlong belt have been discovered, including the Huoshikashi, Kalawala, Xiaoerbulong, Dabudaer, Sansu, Tatulugou, Kangxiwa, Zhongfulugou, No.…”

Petrogenesis and tectonic-magmatic context of emplacement of lepidolite and petalite pegmatites from the Fregeneda-Almendra field (Variscan Central Iberian Zone): clues from Nb-Ta-Sn oxide U-Pb geochronology and mineral geochemistry

“…To our knowledge, no closure temperature data are available for the CGM U-Pb system. However, pegmatite geochronology studies based on different isotopic systems generally report mica 40 Ar/ 39 Ar (and apatite U-Pb) ages significantly younger than CGM and cassiterite U-Pb ages, whereas CGM and cassiterite U-Pb ages are commonly similar to zircon U-Pb ages (e.g., Van Lichtervelde et al, 2017;Li et al, 2019;Hao-Yu et al, 2023). Therefore, the cassiterite and CGM U-Pb systems are much more likely to have recorded the age of emplacement of Li-pegmatites from the FA field compared to mica Ar-Ar ages.…”

Late Jurassic Wenjiaping high Sr/Y granite: A product of partial melting of the Precambrian basement rocks trigged by lithospheric extension in the Songpan–Garzê fold belt, SW China

“…The Songpan–Garzê fold belt (SGFB), sandwiched between the Qiangtang, Kunlun–Qaidam, North China, and South China blocks (Figure 1a; Roger et al, 2003), is an important tectono‐magmatic belt and Li–Be–Sn–Cu–Au polymetallic metallogenic belt (e.g., Li, Li, Chou, Wang, & Xiong, 2019; Roger, Jolivet, & Malavieille, 2010; Xu et al, 2020; Xu, Hou, & Wang, 1992; Zhan et al, 2020; Zhao, Wang, Groves, & Deng, 2019; Zhou et al, 2017) in the eastern margin of the Tibetan Plateau. Due to its unique inverted triangle shape, orogenic polarity, sedimentation, and tectonic evolution, the SGFB is known as the “Chinese Geological Bermuda” (Xu et al, 1992).…”