Updated digital paleogeography for East Tethys from Middle Permian to Middle Triassic

Abstract

Deep-time geographic maps are the setting base of geological research and integrated windows for looking the past earth. Reconstructing paleogeography involves the evolution of the earth’s surface tectonic process, the pattern of land and sea, climate, and biology in geological history. To now, an advancing trend is developing digital paleogeographic model to replace the traditional maps. There already have been various global paleogeographic models based on digital softs, there is still a lack of intelligent or efficient tools for updating these paleogeographic models or creating new maps via integrating tectonic, lithofacies, paleontology, and paleoclimate data. In this study, a case study of the comprehensive paleogeographic reconstruction is carried out for the Middle Permian-Middle Triassic East Tethys, where is highly concerned and rich in geological data accumulation. The digital maps are reconstructed by the combination of automatic mapping with machine learning and manual correction. We use the newly upgraded paleomagnetic, geological and paleontological data to restore the paleoposition of the East Asian blocks at 260, 250 and 240 Ma, which shows the Paleo-Tethys Ocean (PTO) had a wider east-west range than the previous version due to a new paleolongitude of South China at 260 Ma through adopting the method of the Torsvik et al. (2008). Our model shows the multiple microblocks in the PTO were divided into north and south branches, which were semi-closed with several narrow seaways rather than total-closed at 260 Ma. Based on the newly lithofacies paleogeographic atlas of China and marine fossils data, we updated the surface landscape on our new block-pattern by developing a method of automatic mapping paleotopography with manual supervised machine learning.