New findings suggest Earth’s early tectonics shifted from a squishy-lid regime to cooling and fracturing that eventually enabled plate tectonics, while also offering explanations for Venus’s coronae through episodic-squishy or plutonic-squishy lid states.

The research posits a unified view of Earth and Venus evolution, showing Venus-like patterns emerge under episodic or plutonic squishy-lid conditions within a single theoretical framework.

The study proposes Earth may have passed through a squishy-lid phase during cooling, priming its lithosphere for full plate tectonics later on.

The findings are published in Nature Communications in 2025 by Tianyang Lyu, Man Hoi Lee, Guochun Zhao and colleagues.

Published late November, the work maps six tectonic regimes under varying physical conditions to outline likely transition pathways as planets cool.

A comprehensive regime diagram delineates these six states and highlights probable transitions as planetary bodies lose heat over time.

Researchers at The University of Hong Kong used advanced numerical models to classify six distinct terrestrial-planet tectonic regimes, including a newly identified episodic-squishy lid.

The study ties tectonics to broader questions of astrobiology and mission planning by linking a planet’s thermal evolution with atmospheric development and habitability.

The model introduces a memory effect in tectonics, showing that past lithospheric weakening can bias and predict future transitions along cooling trajectories.

This hysteresis concept indicates that transitions between regimes follow more predictable paths as planets evolve and cool.

Understanding lithospheric weakening and regime transitions could inform exoplanet habitability assessments by indicating which worlds might sustain stable climates and life-supporting conditions.

The six-regime framework provides a quantitative lens to explain differences between Earth’s plate tectonics and Venus’s geology and to model planetary tectonic evolution.