Title: A song of ice and fire and CO2: Linking seafloor volcanism to rising carbon dioxide after the last ice age
Abstract: Seafloor volcanism at ocean spreading centers may have played an important role in late Pleistocene glacial terminations by increasing the global inventory of the greenhouse gas carbon dioxide (CO2). Gulf of California geology and hydrography offer a unique opportunity to quantify this carbon contribution because CO2 from local seafloor volcanism will reduce/reverse the vertical gradient of seawater radiocarbon (14C). We reconstructed this surface-to-deep gradient by measuring the 14C content of seafloor- and surface-dwelling foraminifera and find several surface-deep 14C reversals during the most recent deglaciation—a 14C distribution that has no analog in the modern ocean. We interpret these observations as representing increased CO2 efflux from the seafloor during deglaciation, linking plate tectonics with the carbon cycle and global climate via enhanced seafloor volcanism.