Towards interactive global paleogeographic maps, new reconstructions at 60, 40 and 20 Ma

Paleogeographic maps are essential tools for understanding Earth system dynamics. They provide boundary conditions for climate and geodynamic modelling, for analysing surface processes and biotic interactions. However, the temporal and spatial distribution of key features such as seaways and mountain belts that govern climate changes and biotic interchange differ between various paleogeographies that require regular updates with new data and models. We developed a reproducible and systematic approach to paleogeographic recon-struction and provide a set of worldwide Cenozoic paleogeographic maps at 60, 40 and 20 Ma. We followed a six-stage methodology that integrates an extensive review of geological data into a coherent plate tectonic model using the open source software GPlates. (1) We generated a global plate kinematic model, and reconstructed intensely-deformed plate boundaries using a review of structural, paleomagnetic and other geologic data in six key regions: the Andes, the North American Cordillera, the Scotia Arc, Africa, the Mediterranean region and the Tibetan-Himalayan collision zone. (2) We modified previously published paleobathymetry in several regions where continental and oceanic crust overlap due to differences in the plate models. (3) We then defined pale-oshorelines using updated fossil and geologic databases to locate the terrestrial to marine transition. (4) We applied isostatic compensation in polar regions and global eustatic sea level adjustments. (5) Paleoelevations were estimated using a broad range of data including thermochronology and stable isotopes, combined with paleobotanical (mostly pollen and leaf physiognomy), structural and geomorphological data. We address ongoing controversies on the mechanisms and chronology of India-Asia collision by providing alternate re-constructions for each time slice. We finally discuss the implications of our reconstructions on the Cenozoic evolution of continental weatherability and review methodological limitations and potential improvements. Future addition of new data, tools and reconstructions can be accommodated through a dedicated interactive website tool (https://map.paleoenvironment.eu/) that enables users to interactively upload and download data and compare with other models, and generate their own plots. Our aim is to regularly update the models pre-sented here with new data as they become available.

Automated summary

In this study, a reproducible and systematic approach to paleogeographic reconstruction was developed, resulting in worldwide Cenozoic paleogeographic maps at 60, 40, and 20 Ma. Utilizing extensive geological data, a global plate kinematic model was generated, and key features such as paleo-shorelines and paleo-elevations were defined and estimated. The study also addresses controversies in the India-Asia collision mechanisms and provides alternate reconstructions for each time slice.