Climatically driven emissions of hydrocarbons from marine sediments during deglaciation

Abstract

Marine hydrocarbon seepage emits oil and gas, including methane (~30 Tg CH4/year), to the ocean and atmosphere. Sediments from the California margin contain preserved tar, primarily formed via hydrocarbon weathering at the sea surface. We present a record of variation in the abundance of tar in sediments for the past 32ky, providing evidence for increases in hydrocarbon emissions prior to and during Termination IA (16-14 ka) and again over Termination IB (11-10 ka). Our study provides the first direct evidence for increased hydrocarbon seepage associated with deglacial warming via tar abundance in marine sediments, independent of previous geochemical proxies. Climate-sensitive gas hydrates may modulate thermogenic hydrocarbon seepage during deglaciation.