Palaeogeography and paleoelevation through time: controls on weatherability and long-term CO ₂ evolution

Palaeogeography plays a fundamental control on Earth’s long-term climate by regulating the efficiency of silicate weathering, the primary negative feedback stabilizing atmospheric CO ₂ over geological timescales. Accurate reconstructions of past land distribution, topography, and shelf geometry are therefore essential for quantifying weatherability and modelling deep-time climate–carbon cycle interactions. In this study, we present a new Palaeozoic palaeogeographic and paleoelevation model that can be extended for the whole Phanerozoic. Using updated plate tectonic models, fossil-constrained land–sea boundaries, climatically sensitive lithologies, and physically informed elevation classes derived from modern Earth statistics, we produce global 10 Myr-interval maps that include seven topographic layers from deep shelves (−200 m) to high mountains (>4 km). Our approach improves estimates of exposed land area, shallow and deep continental shelves, and regions of high weatherability. We show that differences in land distribution within ±10° of the equator and within climatically defined high-weatherability zones, strongly affect CO ₂ predictions in carbon-cycle models, particularly during the Early Palaeozoic and the Devonian. The new reconstructions refine Palaeozoic sea-level estimates and reveal how evolving continental elevations modulated silicate weathering intensity and contributed to transitions between greenhouse and icehouse states, including the initiation and termination of the Late Palaeozoic Ice Age.