Story perspectives

Impact Heat Kept Early Earth Crust Molten, Delayed Plate Tectonics

7/3/2026

Summary

Story summary

Researchers Tim Johnson and Craig O’Neill published a Science study that impact heating kept Earth's crust thin and molten.
Models show asteroid impact heat exceeded radiogenic heat (>=4.03 billion years ago), keeping the crust molten below few kilometres and preventing plates until rates fell ~3.9 billion years ago.
The crust then cooled, thickened to ~30 km, and produced rocks like the ~4.0 billion-year-old Acasta Gneiss, which the authors cite as explaining the Hadean record.

1 of 1

Story summary

Researchers Tim Johnson and Craig O’Neill published a Science study that impact heating kept Earth's crust thin and molten.
Models show asteroid impact heat exceeded radiogenic heat (>=4.03 billion years ago), keeping the crust molten below few kilometres and preventing plates until rates fell ~3.9 billion years ago.
The crust then cooled, thickened to ~30 km, and produced rocks like the ~4.0 billion-year-old Acasta Gneiss, which the authors cite as explaining the Hadean record.