An interesting development at http://phys.org/print347820987.html … the Isthmus of Panama formed between 17 and 15 million years ago rather than 3 million years ago, according to research published in the journal Science that used a novel way of dating zircon in rocks (April 12th, see www.sciencemag.org/lookup/doi/10.1126/science.aaa2815). The new dates are roughly contemporary with the time it is thought an ice cap fetched up on the Antarctic continent. However, fossilised wood was discovered on Antarctica that has been dated between 3 and 2 million years ago – thus conforming with the new dating technique, and the old. So what is the real date?
Unfortunately, the new research has rubbed up against several major anchors that underpin the conventional uniformitarian model of the past. These are hitched to the 3 million years date. These are i) a movement of animals from South to North America (and vice versa, ii) and climatic changes blamed on the severance of the open water between the Pacific and the Atlantic. This is important as it involves the inception of the Gulf Stream, and the ocean circulation system from the Southern Ocean to the Arctic Ocean (by way of the Atlantic and without losing any water diverted through a gap in central America). In addition, the emergence of ice sheets in the northern hemisphere is supposedly closely linked to the origin of the isthmus – and the Pleistocene Ice Ages are closely dated from 3 million years ago. If the new dates are correct some adjustment to major pillars of mainstream thinking will be necessary. They won't be able to invent a new geological period such as occurred when the Ice Age theory was adopted (the Pleistocene) nor will they be able to extend it to 15 million years ago – we already have plenty of dated geology that fills that gap. Mind you, never underestimate the ability of uniformitarians to provide themselves with wriggle room.
At http://phys.org/print347797643.html … the piece stars off – 'the onset of northern hemispheric glaciation cycles 3 million years ago has drastically shaped Arctic climate'. Hence, we have a deeply rooted anchor that will now have to be re-evaluated. The research here was published in Earth and Planetary Science Letters (April, 2015). It is based on ferromanganese cursts which are said to provide a record of past climate change. Laminated growth is said to be comparable to tree rings – or that is the argument. Ferromanganese crusts appear to support the mainstream glaciation model.