Revisiting Ediacaran to early Cambrian depositional history of the western North China: Did it remain passive until mid-Paleozoic?

Abstract

Whether the North China Block (NCB) remained extension from its cratonization to mid-Paleozoic is questionable. Here, we conducted a synthesis of zircon U-Pb data of Statherian–Ordovician sandstones to make a historical review of provenance changes in the western NCB through time. In contrast to typical NCB basement sources characterized by ca. 2.7–1.8 Ga ages with spectral peaks at ca. 2.5 and 1.9 Ga during much of ca. 1.8–0.45 Ga, Ediacaran to Cambrian Stage 3 succussions contain abundant zircons with Meso- to Neoproterozoic ages. The exotic provenance, further verified by southeastward paleo-flow, implies sources from the western Bainaimiao arc terrane (BAT), where basement rocks with suitable ages exist. Hence, the BAT should evolve at the NCB margin before ca. 0.56 Ga, but after rifting of the NCB (until ca. 773 Ma). This event led to a craton-wide stratigraphic break intervening Mesoproterozoic–Ediacaran. Presence of 521–515 Ma detrital zircons in the Cambrian Stage 3 strata indicates subduction onset of the Paleo-Asian Ocean before ca. 515 Ma, coincident with the Precambrian-Cambrian boundary paraconformity. A sequence of depositional shifts triggered by tectonic activities of the BAT unveil a complicated plate re-organization history of the northern NCB, contesting the NCB remained passive from Statherian. Supplementary material: https://doi.org/10.6084/m9.figshare.c.7040743