Western Hemisphere seismic tomography at 175 to 550 km depths showing giant ring structures. AusIMM webinar Part 10.
Visit the AusIMM Webinar at https://www.ausimm.com/videos/community-event/south-west-wageoscience-society—digital-tech-talk-new-discoveries-in-the-structural-geology-mineralization–exploration-targeting-of-north-america/ .
Seismic tomographic research under North and South America, Africa and Eastern Europe from 170 – 550 km depth shows giant ring structures. It is suggested these formed before or during the Late Heavy Bombardment from 4.1 to 3.8 billion years ago. They exist from the surface down to at least 600 km depth. These relatively undeformed rings occur in the supposed mobile mantle. So, Earth down to 600 km depth is not mobile and so the evolution of Earth by earth-wide Plate Tectonics cannot be correct and needs revision.