Earth's Plate Tectonics: Recent Shifts and Ancient Origins

A new study suggests that Earth's plate tectonics may be a more recent feature of its geologic history. Researchers from the University of Copenhagen found evidence that convection in the mantle was stratified into upper and lower mantle regions that were isolated from each other for most of Earth's history. This is in contrast to the current understanding of plate tectonics, where subducting plates sink to the lower mantle. By analyzing the isotopic composition of titanium in rocks, the scientists were able to trace the recycling and mixing of tectonic plates in Earth's mantle. The study also suggests the existence of a primordial mantle reservoir in the deep Earth, which could provide insights into Earth's original composition and the development of life.