Deep and surface driving forces that shape the Earth: Insights from the evolution of the northern South China sea margin

Abstract

The sediments and their temporal and spatial distribution on Earth are the archives of interaction between deep and surface processes. Numerous simulations have attempted to decipher the evolution of landscape and sedimentary basins. However, it remains a challenge to couple paleogeographic evolution with deep geodynamics, especially at the continental margins such as the Northern South China Sea Margin (NSCSM). Here we employ a numerical simulating tool (Badlands) for the tectono-sedimentary evolution of the NSCSM to test and compare our restored interpolated paleo-bathymetries with previously published paleogeography. Based on the subsequent reconstruction of cumulative sediment thicknesses at the distal boundary of the continental margin, we found that the erodibility and elastic thickness of the lithosphere are the best-fitted and the most promising parameters to isostatically deal with deep dynamics in controlling regional topography. According to our findings, the Early Oligocene and Early Miocene are two stages of high erodibility and fast uplifting in the source provenances or weathering regions as well as lithospheric strengthening. In contrast, the lower values of elastic thickness indicate the Eocene rifting and Late Miocene reactivation of extension due to its lithospheric weakening, relative to the post-rift thickening.Plain language summary: Transient deep and surface processes actively participated in the geography of Earth’s landscape and sediment distribution. It takes millions of years for these processes and remains challenging to investigate the past landscape evolution. However, in the era of numerical modelling and more advanced research, it is now possible to solve many scientific questions. This study also attempted to find paleogeographic core findings based on the combined effect of deep and surface processes using a numerical simulation tool, Badland. Finally, we establish an erosion as a surface leading factor and an elastic thickness of lithosphere and mantle convection as the deep dynamic factors, to effect the Earth’s surface landscape and link with the accumulation of sediments.