Estimating the Ice Ages

11 August 2012
Geology

At http://archaeologynewsnetwork.blogspot.co.uk/2012/08/15-million-years-of… … in spite of the claim one wonders if it is really the right title. It begins on the assumption the consensus model based on Milankovitch is right – which might not please everyone. However, it has a few revealing comments, the sort of thing you won't generally come across in textbooks. That is that the ratio of oxygen isotopes (oxygen 18 to oxygen 16) as preserved in fossil foraminifera shells in ocean sediments, is compromised. It is not a proof of the Ice Ages, as such, or as promoted and fed to the masses outside the inner chambers of the scientists. As some have suspected for some time the isotopes record deep sea temperature changes – and do not necessarily measure the amount of ice locked up in ice sheets. This is important as it has been argued isotope changes at 100,000 year intervals, or variously, at 41,000 year intervals, are actually recording the growth and expansion of the ice sheets basic to the consensus theory underlying Ice Age dynamics. One might imagine orbits may influence temperature deep in the oceans but as the research shows this is a very gradual process which leaves one wondering if temperature itself has got anything to do with it and that it may involve other factors otherwise not taken into account. Basically, from what can be derived from the abstract, the new study looks for another way of reconstructing changes in ice volume – the size of the ice sheets. It seems the ratio of magnesium to calcium in foraminifera fossil shells is the answer. Magnesium is more easily absorbed within warmer water. This means that shells with higher levels of magnesium should indicate warm temperatures – at the bottom of the ocean if nowhere else. However, the changes are not as fast as in the old method, and the assumption is that this means the ice sheets grew slowly. Obviously, without reading the whole article there is a chance the wrong end of the stick is taking a bashing, so look out for more information – will post when forthcoming.

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