Sixth Extinction

19 Jul 2017

At ... University of Zurich researchers have homed in on an extinction event around 2 million years ago when a third of large marine animals, or megafauna as they describe them, such as sharks, whales, sea birds and sea turtles appear to have gone missing. Why did they disappear? It could have had an impact on the ocean ecosystem they conclude, drawing a parallel with the role of humans in the modern world. However, the event 2 million years ago was clearly catastrophic, as they go on to show (using models as well as data).

They began by looking at the period between 5.3 million years ago and the beginning of the Holocene (when megafauna on land also disappeared). They therefore draw a parallel with the two events - separated by a long period of time. However, the measurement of ocean life and that of life forms on land seems to differ, in some respects, but one can hardly bring the end of Pliocene down to the same time as the end of the Pleistocene (although Allen and Delair did suggest something like this 30 years ago). All  we need to know is that they say the extinction event 2 million years ago was accompanied by violent sea level fluctuations in shallow coastal regions. Ocean currents, apparently, also underwent change - which may account for some of the disappearance. Turtles, for example, use the ocean currents, and whales have favoured sea ways in their ocean travels, dependent on the food they consume. Some marine animals may have altered their behaviour - but this does not explain why the ocean currents changed or sea levels went up and down. One can imagine mega tsunami events were involved as these would have a greater impact on coastal regions. Ocean currents could have changed as a result of a switch in global climate - or even more dramatic, a change at the axis of rotation (by whatever).

The interesting things is that the same story pops up at a Creation web site (forwarded by Robert). See ... with the headline, 'newly discovered sixth extinction rewrites geology' which is by Brian Thomas, a writer at the Creation Research organisation. He says that Creation research geologists are in general agreement Ice Age super storms deposited the uppermost Pleistocene layers 'after the Flood' - and it all goes downhill from that point. Apparently, they disagree on what went on prior to the Flood (which sounds like the end of the Late Glacial Maximum when indeed a lot of meltwater must have flooded large areas of Euroasia. Did they reach as far as Noah somewhere in the Middle or Near East?. Thomas claims the Palaeogene, Eocene, Oligocene, Miocene, Pliocene and Pleistocene rock strata was long ago arranged according to unique fossils in them. I suspect most geologists would disagree with this simplification as a whole range of other factors are involved. It's rather strange reading how a Creationist is able to seriously quote Genesis 8:13 as a mine for geological information. At the same time Thomas reveals some geological facts that might need chewing on. The five major global extinction events roughly coincide with five megasequences. Each megasequence, he says, have sedimentary rocks thousands of feet thick and can span whole continents. They normally have hard grained rocks such as sandstone at the bottom, and finer sediments such as chalk or silt stone at the top. This appears to once again be a simplification of the rock strata and in reality chalk has sandstone on top (from the Palaeogene era) and clay on top of that. Creationist geologist Andrew Snelling atributed each sequence to a major advance and temporary retreat of flood water surges. In other words, he was aware that ocean waters rose and fell and changed position, and also were liable to overrun continental regions. However, he seeks to fit the evidence into a single Flood event - and therefore condenses considerable earth history into a short space of time. I suppose he is using the eruption of Mount St Helens as an example of what might have happened in the geological record. Layers of sediments were laid down in days and weeks. None of it was sandstone or chalk - but silt or layers of volcanic mud and ash were laid down very quickly. In a global extinction event one might imagine lots of sediment was laid down - as a result of mega-tsunamis or changes in the earth's geoid resulting in rearrangement of the sea levels of the oceans. It suits uniformitarians to use these sediment layers as a measurement of time. To admit sediments can be laid down quickly would undermine the geochronological record. Without that measurement of time mainstream geologists would be unable to determine the length of time between one catastrophic event and the next - or extinction event to give it the proper title. Geologists would therefore not control the debate and all kinds of whacky ideas would come out of the woodwork. I'm not sure why Creationists are obsessed with a young earth - but not all of them are. Why do people take Biblical numbers seriously? They appear to have a symbolical value that literalists are unable to grasp. Having said that Creationists are not on their own or out on a limb. Many people who are virulently opposed to any kind of religion, or the idea of a controlling force in the universe, can display equal measures of faith and obsession. Climate change is just one example of this fixation. All the evidence is contrary - but many educated people are apparently convinced. One can imagine some of the characters involved in the charade being inquisitors in a previous life, putting dissenters of the consensus view on the rack to stretch their iniquities out of them. We ain't much different from the medieval types - not at all.