Detrital zircon record of rivers' sediments in the North Qilian Orogenic Belt: Implications of the tectonic evolution of the northeastern Tibetan Plateau

Abstract

The North Qilian Orogenic Belt (NQOB) is an important element of the northern edge of the Tibetan Plateau, and several rivers run along it. Zircon U–Pb dating, trace elements, and Hf isotopic data derived from the sediments carried by the rivers have been used to deduce the crustal evolution of the NQOB. U–Pb ages obtained from detrital zircons found in the sediments of the Zamu, Zhuanglan, and Beida rivers can be divided into five major age groups, that is, 2,600–1,500, 1,500–1,100, 1,100–650, 550–400, and 360–150 Ma, and the corresponding peaks occur at ~2,450, ~1,750, ~950, ~450, and ~250 Ma. Archean components, which may be derived from the ancient continental nucleus in the region, are rare in the river sediments. The zircon grains with ages of 360–150 Ma are most likely related to crustal thickening and decompression melting in a post‐collisional tectonic setting. The age distribution patterns indicate that the sediments carried by the Zamu, Zhuanglang, and Beida rivers are derived from the NQOB. Furthermore, the Hf isotopic compositions of Meso‐ and Neoarchean, Mesoproterozoic, Grenvillian, Pan‐African, Caledonian, and Hercynian zircon age groups exhibit a wide range of εHf (t) values, suggesting diverse sources. The existence of strongly negative εHf (t) values among the Grenvillian and Paleoproterozoic zircons indicates that the source magma included reworked Palaeoarchean crustal materials. New results indicate that continental rifting and the opening of the Qilian Ocean occurred at 775–520 Ma; the subduction and closure of the Qilian Ocean occurred at 520–440 Ma; arc–continent collision and continental subduction occurred at 440–420 Ma; and orogen collapse and extension occurred at 400–360 Ma. Our study indicates that the formation of the NQOB was mainly related to the evolutionary history of the Proto‐Tethys Ocean.

Magma mixing in the genesis of the Qingshanbao granitoids in the Longshoushan area: Implications for the tectonic evolution of the North Qilian orogenic belt, NW China

“…The formation of granitoids and intermediate rocks in the Longshoushan area is closely related to the collision of the Alxa and Qilian‐Qaidam blocks, caused by the continuous reduction of the North Qilian Ocean in the Early Palaeozoic (Yang et al, 2018; Fu et al, 2019; Kang et al, 2019). Regarding the time limits for each stage of the collision, Song, Niu, Zhang, and Zhang (2009), Song et al (2013) suggested that the Qilian Ocean had completely closed ca.…”

The Formation of the North Qilian Shan through Time: Clues from Detrital Zircon Fission-Track Data from Modern River Sediments

“…Detrital zircon grains from rivers in the western parts of the North Qilian Shan (location 1 on Figure 1B) yielded five major U-Pb peak ages at 273 Ma, 462 Ma, 756 Ma, 1835 Ma and 2440 Ma [92] (Figure 5a). Detrital zircons found in the river sediments from the central parts of the North Qilian Shan (location 2 on Figure 1B) can again be divided into five major U-Pb peak ages at 267 Ma, 443 Ma, 973 Ma, 1776 Ma and 2481 Ma [93] (Figure 5b). Detrital zircons from the Hei River (locations 3 on Figure 1B) still show five major U-Pb peak ages at 270 Ma, 450 Ma, 950 Ma, 1850 Ma and 2450 Ma, lacking the 756 Ma peak observed in the western North Qilian Shan River [91] (Figure 5c).…”

“…However, it seems that the Hei River does not reach the 756 Ma source observed in the western North Qilian Shan River. [92]), Central North Qilian Shan ((b), [93]), whole Hei River ((c), [90]) with those from the North Qilian Shan ((d), [6,35,36,90]).…”

“…Figure 5. Comparison of the U-Pb age peaks of detrital river zircon grains from Western North Qilian Shan ((a),[92]), Central North Qilian Shan ((b),[93]), whole Hei River ((c),[90]) with those from the North Qilian Shan ((d),[6,35,36,90]). …”

Microtexture and U–Pb geochronology of detrital zircon grains in the Chachalacas beach, Veracruz State, Gulf of Mexico

“…Traditionally, in provenance studies, detrital zircon grain ages are compared with ages of probable source terranes, which delivered sediments to the depositional basin (Margalef et al, 2016;Shi et al, 2020;Tong et al, 2019;Wang, Wu, et al, 2018). On the other hand, numerous studies have proved that U-Pb dating of detrital zircon grains is a useful tool to reconstruct the tectonic evolution of a sedimentary basin, as well as to infer sediment pathway (Chaudhuri, Banerjee, & Le Pera, 2018;Gärtner et al, 2016;Kang et al, 2019;Pulsipher & Dehler, 2019;Saha, Burley, & Banerjee, 2018;Zhao et al, 2020).…”