The 27.5-million-year cycle of geological activity – Phys.org News Science News The 27.5-million-year cycle of geological activity Phys.org Source: Science News June 18, 2021/by PR PR http://gulfstrategic.com/gc/wp-content/uploads/logo_final.jpg 0 0 PR PR http://gulfstrategic.com/gc/wp-content/uploads/logo_final.jpg PR PR2021-06-18 12:28:222021-06-18 17:06:01The 27.5-million-year cycle of geological activity - Phys.org