Limited sulfur degassing and muted environmental impact of Ontong Java Plateau lavas

The mainly deep-submarine Ontong Java Plateau (OJP) is the result of largest outpouring lava in geologic record. Volcanic events this magnitude can have dramatic environmental impacts due to volatile emissions. We report new S measurements naturally glassy, olivine-hosted melt inclusions and pillow basalt glasses from OJP. combined these data with previous OJP quantify degassing a suite glasses. Comparison an model suggests lavas that erupted at depths ~>1500 m did not degas S; ~<1500 degassed up ~40% initial S, but likely made small fraction lavas. This despite its large volume compared continental igneous provinces (LIPs), emitted less potentially contributing muted impact. may provide framework for temporal evolution oceanic LIPs, early eruptions great water releasing limited no later shallow larger, still amounts S. also implications LIP magmas, which release significant CO2 during intrusive activity, magmatic emissions only becoming important extrusive phases.