Compression‐Induced Anomalous Subsidence in the Extensional Sedimentary Basin: A Numerical Study From the Pearl River Mouth Basin, Northern South China Sea Margin

Abstract

AbstractCompressional uplift has long been considered as the basic response to basin inversion. However, significant discrepancies are recently observed in the Pearl River Mouth Basin (PRMB), where anomalous subsidence occurs during the Miocene compression phase. Whether the subsidence is another scenario that is associated with the tectonic inversion under certain circumstances remains unknown. Here we conduct systematic numerical modeling to explore the patterns of rift basin evolution from extension to compression. Our results show that two distinct inversion types develop depending on the stretching degree and tectonic quiescence. A less stretched continental crust would facilitate the uplift of basin center accompanied by erosion during shortening; otherwise, the basin center exhibits anomalous subsidence with abundant sediment accumulation. We further demonstrate that these two contrasting types, consistent with the Miocene evolutionary pathways of the eastern and western PRMB, respectively, are strongly conditioned by the along‐strike variation of stretching degree during extension.