Paleoproterozoic transition in tectonic regime recorded by the Eastern Block of the North China Craton: evidence from detrital zircons of the Langzishan Formation, Jiao-Liao-Ji Belt

ABSTRACTThe Eastern Block of the North China Craton records Paleoproterozoic oceanic plate subduction, the opening and subsequent closure of a back-arc basin, and a following collisional orogenic event to generate the Jiao-Liao-Ji Belt (JLJB). However, the processes involved in the initiation of subduction remain unclear. This study presents U–Pb age and trace elemental data for detrital zircons from the Langzishan Formation, the lowermost sedimentary unit within the JLJB, to constrain the provenance, depositional age, and depositional environment of this formation as well as the processes involved in the Paleoproterozoic transition in tectonic regime recorded by the Eastern Block. The U–Pb ages of these detrital zircons yield one major age peak at ca. 2529, and three minor age peaks at ca. 2700, ca. 2347, and ca. 2198 Ma. Provenance analysis indicates that the Langzishan Formation was derived from basement rocks in the Longgang Block with minor contributions from early magmatic rocks within the JLJB. Det...