Substantiating the Paleozoic sedimentary record of the tectonic transition from a passive to an active continental margin along the eastern margin of Eurasia

• DOI: 10.1130/b37873.1
• Publication Date: 2025-02-19T23:34:11Z
• Authors: Ning-Chen Sun; Jian-Bo Zhou; Zhong-Jie Xu; Simon A. Wilde; Ri-Hui Cheng; Da-Zhi Xu; Gong-Yu Li

The Jiamusi Massif in the eastern margin of Eurasia, located at the tectonic transition belt between the Paleo-Asian Ocean and the Paleo-Pacific tectonic domain, underwent a pivotal transition from a passive to active continental margin during the late Paleozoic. However, the exact timing and geodynamics of this transition remain controversial. To address this issue, this paper presents new petrological, mineralogical, detrital zircon U-Pb geochronology, and zircon trace element analyses of sedimentary rocks sourced from both the Heitai and Zhenzishan formations in the Jiamusi Massif. The results indicate that the Heitai Formation is a clastic-carbonate rock association deposited on stable crust. In contrast, the Zhenzishan Formation is a series of molasse facies accompanied by volcanic activity. New detrital zircon data from this study, together with the distribution of sedimentary facies, indicate that the provenance of the Heitai Formation was mainly derived from magmatic rocks of Erguna-Xing’an and Songliao massifs and basement rocks of the Jiamusi Massif. In contrast, the provenance of the Zhenzishan Formation was derived from the basement rocks and the discernible arc of the Jiamusi Massif. The weighted mean 206Pb/238U ages for the youngest zircons indicate that the maximum depositional ages of the Heitai and Zhenzishan formations were estimated at ca. 375 Ma and ca. 305 Ma, respectively. These data support, in the eastern Jiamusi Massif, a transition from a passive to an active continental margin occurred between the Late Devonian and late Carboniferous (375−305 Ma), which was likely related to subduction of the Mongol-Okhotsk Ocean (a part of Panthalassa), which is also an important tectonic transition event in the eastern margin of Eurasia.