At http://phys.org/print300352509.html … a core sample from New Jersey geology, in a region once beneath the sea (55 million years ago) has clay bands around 2cm thick that appear to have been laid down rhythmically, or cyclic. As such, they were akin to tree rings, providing an annual pulse, a yearly amount laid down as strata. I've heard similar wave patterns in sediments described as Milankovitch periods but annual changes preserved in the geological record doesn't appear to comply with uniformitarian geochronological parameters. Why annual we might ask – why not a wave pattern over days and weeks?
The authors of the PNAS paper are eager to make a connection with modern CAGW – presumably to further funding for more research. Geology is one of the sciences that can latch on to this gravy train – or gold mine in some circumstances. The claim is that there was a doubling of co2 and the surface of the ocean turned acidic over a period of weeks and months and global temperatures rose five degrees withing just 13 years – thereby adding the doomsaying song sheet (for free). Obviously, the CAGW element may have been an add-on and the main body of the article may not have had such a definite focus. The press release was presented by Rutgers University. Presumably what was really found was evidence of a catastrophic event which took place very quickly – more rapidly than 13 years. It may have even involved acidification of the ocean- especially if a large amount of surface water was displaced (reducing the amount of co2 at the ocean surface and increasing it in the atmosphere). We must bear in mind that papers like this involve a lot of field research and should not be dismissed just because they have made use of the current CAGW paradigm. On the other hand, the researchers may genuinely believe in the consensus – and global warming as a fact of life. What can you say in that situation.