Over the course of time, this may have led to peaks in deep mantle melting and possibly to major volcanic events at the Earth's surface. (sciencedaily.com)
This crustal weakness allowed unusually high heat flow from deeper mantle sources to «super-heat» the highly organic Niobrara source rocks, which in turn generated the significant oil and gas deposits now contained in the Niobrara and Codell formations. (pdce.com)
But releases of oxygen from upwelling of deep mantle FeO2 patches could provide an abiotic explanation for the phenomenon, they say. (sciencedaily.com)