Positioning the Yangtze Block within Nuna: Constraints from Paleoproterozoic granitoids in North Vietnam

•Ca. 2.30–2.27 Ga, 1.85–1.83 Ga, and 1.75 Ga granitoids in the Phan Si Pan Complex, north Vietnam.•The two older episodes of granitoids formed by partial melting of Archean basements.•The ca. 1.75 Ga trondhjemite formed by partial melting of juvenile crust.•The Yangtze Block was located between southern Siberia and northern Laurentia within Nuna. There is no consensus on the Precambrian paleogeographic reconstructions of Yangtze Block through the various supercontinent cycles and its linkage to other continental blocks. New data on the Paleoproterozoic tectonic history of the block enables linkage with other major Nuna-forming continents to be constrained. Zircon U-Pb-Hf isotopic and whole-rock elemental data highlight three episodes of Paleoproterozoic granitoids, dated at 2.30–2.27 Ga, 1.85–1.83 Ga, and 1.75 Ga from the Phan Si Pan Complex of the Phan Si Pan Zone, a southeast extension of the Yangtze Block in north Vietnam. The older two episodes of granitoid emplacement have negative εHf(t) values with similar TDM2 ages of 3.3–2.9 Ga, which suggest reworking of Archean basement rocks possibly at syn- to post-collisional settings. The 1.75 Ga A-type trondhjemite with positive εHf(t) values (0 to + 9) formed by partial melting of Paleoproterozoic juvenile crustal materials along with some mantle addition, most likely related to an intra-plate rift setting. Integrating the new results with compilations throughout the Yangtze Block, we suggest that the northern and southwestern Yangtze have different Archean and earliest Paleoproterozoic histories. Furthermore, correlations of Archean-Paleoproterozoic tectono-thermal and detrital zircon signatures between southwestern Yangtze and north Laurentia, and between northern Yangtze and southern Siberia, suggest they were close neighbors at these times. The collision between the northern and southwestern Yangtze in the late Paleoproterozoic is inferred to have led to the assembly of Laurentia and Siberia along a cryptic suture in central Yangtze and widespread crustal magmatism. Thus, we tentatively reconstruct the Yangtze Block as a key tie point between northern Laurentia and southern Siberia within the Nuna Supercontinent.