Machine Learning and Big Data Mining Reveal Earth's Deep Time Crustal Thickness and Tectonic Evolution: A New Chemical Mohometry Approach

Quantitative analysis of crustal thickness evolution across deep time poses critical insights into the planet's geological history. It may help uncover new areas with potential critical mineral deposits and reveal the impacts of crustal thickness and elevation changes on the development of the atmosphere, hydrosphere, and biosphere. However, most existing estimation methods are restricted to arc-related magmas, limiting their broader application. By mining extensive geochemical data from present-day subduction zones, collision orogenic belts, and non-subduction-related intraplate igneous rock samples worldwide, along with their corresponding Moho depths during magmatism, we have developed a machine learning-based mohometry linking geochemical data to Moho depth, which is universally applicable in reconstructing ancient orogenic systems' paleo-crustal evolution and tracking complex tectonic histories in both spatial and temporal dimensions. Our novel mohometry model demonstrates robust performance, achieving an R² of 0.937 and an Root Mean Squared Error of 4.3 km. Feature importance filtering highlights key geochemical proxies, allowing for accurate paleo-crustal thickness estimation even when many elements are missing. Model validation in southern Tibet and the South China Block, regions characterized by well-constrained crustal histories and complex tectonic processes, demonstrates its broad applicability. Reconstructed paleo-crustal thickness records reveal a strong correlation between crustal thickening events and the formation of porphyry ore deposits, offering new insights for mineral exploration in ancient orogens subjected to significant surface erosion. By enabling the reconstruction of crustal thickness across geological timescales, this model enhances our understanding of Earth's internal dynamics and their interactions with surface processes, thereby advancing our comprehension of Earth's geological history.