Thermogenic methane release as a cause for the long duration of the PETM

The Paleocene-Eocene Thermal Maximum (PETM) was a period of global warming associated with rapid massive ¹³C-depleted carbon input, often mentioned as a paleoanalog for future climate change and associated feedbacks. One hypothesized carbon source is intrusive volcanism in the North Atlantic region, but rigid dating lacks. We date thermogenic methane release from a hydrothermal vent and find that it postdates the onset of the PETM but correlates to a period of additional carbon injection within the PETM. This study provides evidence of carbon release during the PETM from a reservoir (i.e., organic matter in sedimentary rocks) and implies that carbon release from the vent systems should be included in all future considerations regarding PETM carbon cycling.