Tectonostratigraphic evolution of the Northeast South China Sea Rifted Margin: From Mesozoic orogeny to Present

We present a new integrated tectonostratigraphic framework for the proximal-to-distal rifted margin of the Northeast South China Sea, based on a review of seismic and borehole observations, as well as crustal thickness variations determined from a gravity inversion scheme. The structural domains of the NE SCS shaped by Cenozoic rifting include the proximal (Northern Rift System and Penghu-Peikang High), necking (Tainan Basin, Central High, and its southern vicinities), and distal domains (Southern Rift System and Southern High). Rifting (Late Paleocene to Early Oligocene) occurred synchronously throughout the margin and was accommodated by large-offset and low-angle normal faults. This resulted in localized rift basins filled by marine/deltaic sedimentary rocks in the proximal domain and a sediment-starved, likely deep-marine setting in the distal domain. During the post-rift period (Early Oligocene to latest Miocene), shelf-dominated deposition prevailed north of the Central High, whereas a deep-marine environment is interpreted to its south. This overall trend persisted during the foreland basin sedimentation linked to the Taiwan orogen (latest Miocene to recent). The comparison of the NE SCS rifted margin with the adjacent Pearl River Mouth rifted margin shows differences in both their crustal structure and sediment infilling history. Their contrasting crustal structures are interpreted as a response to rifting processes that differ due to initially contrasting crustal rheology and the proximity/magnitude of sediment source areas. More generally, this study highlights how the dynamic evolution of marginal sea basins drives rapid changes in rifting styles and sedimentary infill during and after rifting.