# Orogeny and topography influenced Jurassic–Cretaceous terrestrial ecosystem evolution in northeastern Asia

## TL;DR

This study shows how tectonic activity and changing landscapes shaped ancient ecosystems in northeastern Asia during the Jurassic and Cretaceous periods.

## Contribution

The study links tectonic transitions to the evolution of distinct Jurassic–Cretaceous biotas in northeastern Asia.

## Key findings

- Mid–Late Jurassic plate convergence led to high elevations and the Yanliao Biota's emergence.
- Early Cretaceous tectonic extension diversified the Jehol Biota through rugged topography and climate heterogeneity.
- Northeastern Asia's upland provided ecological niches for biodiversity during a cool, heterogeneous climate.

## Abstract

Tectonic processes are often invoked to explain ecosystem changes, but their precise effects remain elusive. This study focuses on Jurassic–Cretaceous Northeastern Asia, linking the flourishing of the globally exceptional Yanliao and Jehol Biotas, which are temporally successive biotas with distinct species composition, to a prominent tectonic transition from crustal shortening to extension. We estimated paleo-elevation and paleo-temperature variations using whole-rock chemical parameters from Jurassic–Early Cretaceous continental arcs. Combined with published paleoclimate and paleontological records, our findings suggest that Mid–Late Jurassic plate convergence in Northeastern Asia created high elevations and complex topography with vertically zoned micro-environments, promoting the emergence of Yanliao Biota. In the Early Cretaceous, following recovery from a warm and arid climate interval across the Jurassic–Cretaceous transition, enhanced topographic ruggedness due to tectonic extension and local topographic/climate heterogeneity, diversified the Jehol Biota. This highly sculpted Northeastern Asia upland (2.0–4.5 km) hosted a wide spectrum of ecological niches under a relatively cool but heterogeneous climate, creating a key cradle for biodiversification.