Global lithospheric thickness reconstruction using machine learning

The lithosphere, as the outermost solid layer of our planet, preserves a
progressively more fragmentary record of geological events and processes
from Earth's history the further back in time one looks. Thus, the
evolution of lithospheric thickness and its cascading impacts on Earth’s
tectonic system are presently unknown. Herein, we track the lithospheric
thickness history using machine learning based on lithogeochemical big
data of basalt. Our results demonstrate that four dramatic lithospheric
thinning events occurred during the Paleoarchean, early Paleoproterozoic,
Neoproterozoic, and Phanerozoic with intermediate thickening scenarios.
These events respectively correspond to supercontinent breakup and
assembly periods. Causality investigation further indicates that crustal
metamorphic and deformation styles are the feedback of lithospheric
thickness. Cross-correlation between lithospheric thickness and
metamorphic thermal gradients record the transition from intra-oceanic
subduction systems to continental margin plus intra-oceanic in the
Paleoarchean and Mesoarchean, and a progressive emergence of large thick
continents that allow supercontinent growth, which promoted assembly of
the first supercontinent during the Neoarchean.