Dating,periods of time, even cycles of the ebb and flow of global temperatures, have been aided and abetted by the lowly foraminifera, or rather, the shells of tiny sea creatures (marine plankton). It was always assumed foraminifera isotopes record the temperatures above where they are found on the ocean or sea floor. They are embedded, most importantly, in Ice Age theory and the idea of 100,000 year cycles of cold climate and brief warming episodes.
When you think about that cycle it seems so wonky you just know something is not quite right. It's another of those consensus theories that is accepted as science proven and not a lot of thought is given to it otherwise. Science becomes the authority – but why did they come up with this idea of 100,000 year cycles? Well, the Sun has a 90,000 plus years cycle around its barycentre – but the ocean sediments could not have been telling science that – or could they?
Foraminifera live close to the ocean surface – see http://phys.org/print345384331.html …. where are 'record' the water temperature (via isotopes). Basically, some foraminifera have oxygen isotopes indicating cool temperatures, and others, are common to warmer waters. As they die they settle to the ocean floor. Scientists extract sediment cores and analyse the isotopes preserved in the shells which, they say, are similar to tree rings but on the scale of millions of years (or that is the supposition). The study, published in Nature Communications (march 12th) is said to provide evidence of climate change in the past as a result of the differing oxygen isotopes in the shells. However, and there is always a however, as previously noted in another post, it emerges that foraminifera can drift on the ocean currents before dropping to the bottom of the sea. One might assume the Gulf Stream might play a role – and any other ocean current. A state of the art biophysical computer model was developed by the University of Miami school of marine and atmospheric science. It goes on to say this is not true of all foraminifera flotsam as in regions where currents do not dominate they may well drop down to the ocean bottom when their life cycle comes to an end. In other words, my take, foraminifera are not the firm evidence of temperature change as consensus would allow – and therefore are not evidence of 100,000 year cycles associated with Ice Ages. It is all waffle.
On the other hand, scientists may be right and cynics like me might be wrong. After all, if the Sun has a cycle around its barycentre, that cycle must be preserved somehow in terrestrial life – and why not foraminifera, the humble plankton.