New evidence uncovers origin of 'ghost-arc signatures' in global mid-ocean ridge basalts

Mid-ocean ridge basalts (MORBs), located far from subduction zones, are typically thought to be unaffected by subduction processes. However, some MORBs display arc-like geochemical signatures—including negative Nb anomalies and elevated H2O/Ce and Ba/Th ratios—referred to as "ghost-arc signatures."