Sequential patterns in Cenozoic marginal basins of the Northwest Pacific

Abstract

AbstractBy using magnetic anomaly identifications, onshore and offshore exploratory wells, ODP drillings, isotopic dating and orthochronology results, this paper summarizes the tectonic event sequence (including extension, back‐arc spreading, subsidence, convergence/compressive deformation and thrusting) of the marginal basins of the NW Pacific and extracted sequence patterns of the marginal basins according to the tectonic event sequence from an array of oil company regional seismic lines and other geological data. Three important evolutionary stages of the Northwestern Pacific (NW Pacific) marginal sea basins are distinguished: from the Palaeocene to Eocene, from Oligocene to Middle Miocene and from the later Middle Miocene to the present day. Each stage corresponds to a rifting sequence (Palaeocene to Eocene), a drifting sequence (Oligocene to Middle Miocene) and a subsidence/convergence sequence (later Middle Miocene to the present day). The rifting sequence and drifting sequence developed sequentially in the South China Sea Basin, from Palaeocene to Eocene and from Oligocene to Middle Miocene, while in the Japan and Okhotsk Sea basins, an early stage rifting sequence was not developed in the Palaeocene to Eocene interval. However, the drifting and rifting sequence developed synchronously from the Oligocene to Middle Miocene. From the Later Miocene time, all the marginal basins of the Northwest Pacific basically stopped drifting and began to enter the subsidence (post‐drifting) stage. An arc‐continent collision from the south caused the formation of a convergence sequence in the southern margin of each marginal basin. The NW Pacific Plate collision with the Kuril–Kamchatka Arc led to the deformation of the subsidence sequence in the southern margin of the Kuril Sea Basin. The NW Pacific Plate convergence with the Japan Arc led to the formation of a convergence sequence in the southern margin of the Japan Sea Basin. The Borneo–Palawan Arc convergence with the Dangerous Grounds–Reed Bank Block in the South China Sea Basin from 15 Ma led to the formation of the convergence sequence in the southern margin of the South China Sea Basin. The degree of thrusting deformation of the convergent sequence increased gradually from north to south in the marginal basins of the Northwest Pacific. Copyright © 2016 John Wiley & Sons, Ltd.