The South China Sea is not a mini-Atlantic: plate-edge rifting vs intra-plate rifting.

Pinxian Wang,Jian Lin,Minghui Zhao,Chi-Yue Huang,Zhimin Jian,Zhen Sun

doi:10.1093/nsr/nwz135

Abstract

The South China Sea, as ‘a non-volcanic passive margin basin’ in the Pacific, has often been considered as a small-scale analogue of the Atlantic. The recent ocean drilling in the northern South China Sea margin found, however, that the Iberian model of non-volcanic rifted margin from the Atlantic does not apply to the South China Sea. In this paper, we review a variety of rifted basins and propose to discriminate two types of rifting basins: plate-edge type such as the South China Sea and intra-plate type like the Atlantic. They not only differ from each other in structure, formation process, lifespan and geographic size, but also occur at different stages of the Wilson cycle. The intra-plate rifting occurred in the Mesozoic and gave rise to large oceans, whereas the plate-edge rifting took place mainly in the mid-Cenozoic, with three-quarters of the basins concentrated in the Western Pacific. As a member of the Western Pacific system of marginal seas, the South China Sea should be studied not in isolation on its origin and evolution, but in a systematic context to include also its neighboring counterparts.

Highlights

Continent break-up and basin formation are two of the fundamental processes in Earth tectonics
The recent ocean drilling in the northern South China Sea margin found, that the Iberian model of non-volcanic rifted margin from the Atlantic does not apply to the South China Sea
Based on literature survey and the recent International Ocean Discovery Programs (IODP) results, this paper demonstrates the differences between the two types of oceanbasin formation, i.e. intra-plate vs plate-edge rifting, which are characteristic of two distinct stages in the Wilson cycle, respectively

Summary

INTRODUCTION

Continent break-up and basin formation are two of the fundamental processes in Earth tectonics. The acoustic basement was penetrated at 8 of the 12 drilled sites in its ocean basin or at the continent–ocean transition (COT), all in water depths exceeding 3700 m. This is the second large-scale drilling campaign of the world’s passive margin after several Ocean Drilling. New IODP findings challenge the prevailing wisdom in applying the Atlantic model of basin opening to the SCS and call for a reconsideration of the process of its formation. Based on literature survey and the recent IODP results, this paper demonstrates the differences between the two types of oceanbasin formation, i.e. intra-plate vs plate-edge rifting, which are characteristic of two distinct stages in the Wilson cycle, respectively. Western Pacific marginal basins are interconnected as a system in their origin and evolution, and the processes of their formation can only be properly understood from inside this collective system

NEW FINDINGS OF OCEAN DRILLING

Shikoku

CONCLUSIONS