3D palaeogeographic reconstructions of the Phanerozoic versus sea-level and Sr-ratio variations

Abstract

A full global geodynamical model over 600 million years (Ma) has been developed at the University of Lausanne during the past 20 years. We show herein how the 2D maps were converted into 3D (i.e., full hypsometry and bathymetry), using a heuristic-based approach. Although the synthetic topography may be viewed as relatively crude, it has the advantage of being applicable anywhere on the globe and at any geological time. The model allows estimating the sea-level changes throughout the Phanerozoic, with the possibility, for the first time, to flood accordingly continental areas. One of the most striking results is the good correlation with “measured” sea-level changes, implying that long-term variations are predominantly tectonically-driven. Volumes of mountain relief are also estimated through time and compared with strontium isotopic ratio (Sr-ratio), commonly thought to reflect mountain belt erosion. The tectonic impact upon the general Sr-ratio trend is shown herein for the first time, although such influence was long been inferred.

Keywords

• palaeogeography
• reconstruction
• hypsometry
• bathymetry
• sea-level
• Sr-ratio
• tectonic-climate relationship