Post‐rift Tectonic History of the Songliao Basin, NE China: Cooling Events and Post‐rift Unconformities Driven by Orogenic Pulses From Plate Boundaries

Abstract

The classic lithosphere‐stretching model predicts that the post‐rift evolution of extensional basin should be exclusively controlled by decaying thermal subsidence. However, the stratigraphy of the Songliao Basin in northeastern China shows that the post‐rift evolution was punctuated by multiple episodes of uplift and exhumation events, commonly attributed to the response to regional tectonic events, including the far‐field compression from plate margins. Three prominent tectonostratigraphic post‐rift unconformities are recognized in the Late Cretaceous strata of the basin: T11, T03, and T02. The subsequent Cenozoic history is less constrained due to the incomplete record of younger deposits. In this paper, we utilize detrital apatite fission track (AFT) thermochronology to unravel the enigmatic timing and origin of post‐rift unconformities. Relating the AFT results to the unconformities and other geological data, we conclude that in the post‐rift stage, the basin experienced a multiepisodic tectonic evolution with four distinct cooling and exhumation events. The thermal history and age pattern document the timing of the unconformities in the Cretaceous succession: the T11 unconformity at ~88–86 Ma, the T03 unconformity at ~79–75 Ma, and the T02 unconformity at ~65–50 Ma. A previously unrecognized Oligocene unconformity is also defined by a ~32–24 Ma cooling event. Tectonically, all the cooling episodes were regional, controlled by plate boundary stresses. We propose that Pacific dynamics influenced the wider part of eastern Asia during the Late Cretaceous until Cenozoic, whereas the far‐field effects of the Neo‐Tethys subduction and collision processes became another tectonic driver in the later Cenozoic.

Low‐temperaturethermochronological insights into the Mesozoic–Cenozoic exhumation history of the Taihang–Lvliangshan region: A review

“…However, the other school of opinion suggests that East Asia has been affected by ocean plate‐induced compression owing to the arc–continent collision associated with the acceleration of Pacific seafloor spreading after ~65 Ma (Hourigan et al, 2009; Konstantinovskaia, 2001). This event resulted in the Late Cretaceous–Early Cenozoic unconformity in the Songliao Basin (Song et al, 2018).…”

Asthenospheric flow through the Izanagi-Pacific slab window and its influence on dynamic topography and intraplate volcanism in East Asia

“…Frontiers in Earth Science frontiersin.org 2019); and the Songliao Basin (SLB, Song et al, 2018). A map of these basins can be found in Figure 1.…”

“…This better represents the true area of the data used in NE China. Given that the Songliao Basin has not undergone significant deformation since the Paleocene (e.g., Song et al, 2018), the locations of the points relative to each other will have remained relatively constant throughout the late Cenozoic. This means that the reconstruction, which keeps these points fixed relative to each other, will result in a reasonable representation of their palaeolocations.…”

“…), and has been commented on as an inter-regional effect (e.g., Wang R. et al, 2020), although its source has remained unclear. Due to the coeval uplift of the Tibetan plateau further west, and the proximity to the Pacific subduction zone to the east, this hiatus is sometimes attributed to a temporary change from an extensional to a compressional stress regime due to far-field effects either from the India-Asia collision (e.g., Song et al, 2018), or from an increase in the convergence rate at the Pacific subduction zone (e.g., Tang et al, 2019). However, the structures of the basins recording this hiatus inferred from seismic stratigraphy and borehole data (e.g., Lin et al, 2008;Qi and Yang, 2010;Cukur et al, 2011;Yang et al, 2016;Song et al, 2018; show no clear signs of compression in the sedimentary layers directly underlying the unconformity associated with this hiatus.…”

“…Due to the coeval uplift of the Tibetan plateau further west, and the proximity to the Pacific subduction zone to the east, this hiatus is sometimes attributed to a temporary change from an extensional to a compressional stress regime due to far-field effects either from the India-Asia collision (e.g., Song et al, 2018), or from an increase in the convergence rate at the Pacific subduction zone (e.g., Tang et al, 2019). However, the structures of the basins recording this hiatus inferred from seismic stratigraphy and borehole data (e.g., Lin et al, 2008;Qi and Yang, 2010;Cukur et al, 2011;Yang et al, 2016;Song et al, 2018; show no clear signs of compression in the sedimentary layers directly underlying the unconformity associated with this hiatus. Indeed, throughout the basins considered, the relevant unconformity truncates extensional or quiescent structures in the underlying layers, showing that structural deformation cannot be the root cause of the stratigraphic hiatus, and proving the need for interregional scale uplift.…”