The North China Basin: An example of a Cenozoic rifted intraplate basin

The North China basin was a stable continental region that has undergone several distinct phases of rifting and subsidence during the Mesozoic and Cenozoic eras. The last major phase, featuring block faulting, rapid subsidence and widespread calc‐alkaline basaltic volcanism, began during early Tertiary time. This intraplate rifting appears to be the result of an approximately 30% extension and thinning of the lithosphere beneath the northeastern China. By the late Tertiary period, active rifting had slowed and postrift thermal subsidence had begun. This regional extension and subsidence resulted in the present day North China basin, a large saucer‐shaped, oil producing basin with thinner crust and lower upper mantle P and S wave velocities than the surrounding regions. During the Quaternary period, however, the subsidence rate increased in the North China basin. The frequent occurrence of destructive earthquakes and observations of relatively high heat flow suggest that the Quaternary tectonic activity differs from the late Tertiary simple thermal subsidence pattern and may indicate a new phase of rifting.