The boundary event is the same as in yesterday's post, the transition from the Palaeocene to the Eocene, but the date is slightly different – 56 million years ago rather than 55 million years ago (but what's a million years in uniformitarian geochronology – a sliver of time equivalent to the thickness of a cat's whisker).
We are told it was a period of rapid and dramatic warming. We aren't told it might involve movement of continental plates, the poles, or outgassing associated with an expanding earth. Mostly, we aren't told that a catastrophic event of some sort might mark the transition – and that might have something to do with the change in climate. All that is said is that the Eocene was warmer than the Palaeocene – but not where in the world it was warmer. Insufficient data exists to say the whole of the Earth had warmed up, the direct result of Eurocentric and N American research. It might have warmed up on a global basis – but it may not have warmed up. All we know is that co2 was involved – and, as an add-on, ocean acidification.
The paper is published in the journal Palaeoceonography – see http://phys.org/print300528850.html where you will see the researchers used a different technique to study the extremely small foraminifera planktonic shells in ocean sediments. As such, they produced some different results to other researchers – it is thought. It was a rather clever technique update involving ion spectrometry and electron probe microanalysis to measure the composition of even smaller preserved fragments of individual shells. They obtained a more correct isotope ratio of foraminifera – warm or cool water plankton isotopes. However, where does this leave all the old research using the previous analytical methodology. We are informed that the old method used a technique that consumed the whole shell. As such, recrystalisation from the PETM breakdown would skew the results. This admission is worrying – is all that foraminifera isotope analysis that glues together the Ice Age theory and 100,000 year Milankovitch cycles to be dropped? Not on your neddy – no way. It's in all the textbooks and is part of university curricula. They wouldn't drop it without a very red face and these people are not the kind to admit mistakes – even when a researcher has it written bold in his paper.