Did Hainan Island (Southern China) Undergo Significant Cenozoic Tectonic Displacement, and Impact Its Biota's Sourcing and Evolution?

Aim

A significant Cenozoic tectonic displacement of Hainan Island has been proposed, suggesting that the island underwent southeastward movement from an Eocene connection with Vietnam and Guangxi to its current location. This hypothesis has been adopted in some studies to explain the biotic origin of Hainan Island. In this study, we aim to critically evaluate the validity of this hypothesis based on available evidence.

Location

Hainan Island and its nearby areas.

Taxon

No specific taxon.

Methods

We reviewed the relevant literature and examined the geological, palaeomagnetic, and biological evidence for the proposed tectonic displacement.

Results

We found that the proposed drift scenario primarily stemmed from palaeomagnetic estimates and simplified geological schematic diagrams, neither of which provided robust evidence or a comprehensive explanation for such movement. Our evaluation incorporating geological, palaeomagnetic, and biological data reveals no definitive evidence for large-scale displacement.

Main Conclusions

Given the complex biogeographic patterns of Hainan Island, we argue that discussions on its origin and evolution should adopt a more cautious attitude, avoiding reliance on assumed drift mechanisms without substantial supporting evidence.