Pleistocene

9 Feb 2010

www.physorg.com January 12th ... the Black Mesa basin in Arizona has underground aquifers created by seepage through the overlying geology. The water contains gases that provide a hint of ancient climate in the region - via palaeohydrological tools that capture noble gases such as neon and helium, elements that resist normal chemical reactions. Initial results show the aquifer was recharged during the last Ice Age and this implies the Jet Stream at that time was much further south than it is today.

www.physorg.com February 5th ... new research from the National Oceanography Centre in Southampton has caused a question mark against the whole idea of cyclic change related to the orbit of the earth around the sun. The Holocene is regarded as the most recent interglacial event - and in many respects there are also clear analogies with previous interglacial warm periods. If the orbit of the earth is the main driver of climate change the current warm period should have ended some two thousand years ago - yet it is still warm. The current research, on plankton shells preserved in sediments at the bottom of the Red Sea, have confirmed the Holocene has overstepped the interglacial norm as predicted by the consensus theory. This is that orbital changes control the Ice Ages (based on the intensity of solar radiation reaching the surface of the earth - calculated on June in the northern hemisphere). The research says the anomaly disappears if the measurement of solar energy across the summer months as a whole, including July and August, is taken into account - a deduction that allows the consensus to adapt rather than change.

Science Daily November 19th ... a research article published in Nature, 29th November 2009, concludes that the water of the earth's oceans might have an extra-terrestrial origin. The question is where did it come from as those comets encountered by space craft recently have all been rocky specimens.

Science Daily November 10th 2009 ... the Netherlands Organisation for Scientific Research has examined climate change over the past 800,000 years (glacials and interglacials) via sedimentary deposits from around the world. Martin Ziegler demonstrated that it is not just solar radiation (or the amount of heat) that is most influential on the strength of the monsoon system but the periodic melting of the ice sheets was a greater factor. This paper would appear to strengthen earlier research by other people that has shown that the polar front and jet stream move up and down with the ice sheet advances and retractions and therefore impinge on the monsoon belt - causing that to move likewise. What is of interest to catastrophists is that periodic fluctuations in the position of the earth's axis are blamed for ice sheet advance and retreat - but what if Ziegler had gone one stage further and looked at what might happen if the axis of rotation did on occasion wobble or wander thereby creating a similar process, but more pronounced, than orbital changes.

www.physorg.com January 10th ... a study in Nature Geoscience suggests the Bering Strait was a driver of global climate during the Ice Ages. Fluctuating sea levels affected ocean currents transporting heat and salinity from the Pacific tropical zone to the Atlantic. As a result of this summer temperatures in North America and Greenland oscillated between warmer and colder phases causing ice sheets to expand or contract - in turn causing global sea levels to rise and fall. Although this seems circular reasoning the scientists concerned think they have found the holy grail, the tipping points that caused the Dansgaard-Oeschger and Heinrich-Bond events. The research found that sea levels in some parts of the world rose and dropped by as much as 30m from 110,000 to 40,000 years ago. This is generally interpreted as orbital change as the earth rotates around the sun leading to ice sheet formation and retraction - but apparently the orbital pattern does not quite fit the geological movement of the ice sheets back and forth, and neither do they explain the changes in sea level (as they are currently known). Hence, the researchers looked for another mechanism and decided the Bering Strait might be the key, a 50 mile wide opening from the Arctic Sea to the Pacific. Supercomputers, it is said, revealed a distinct pattern of warming and cooling - rather, the data fed into those computers revealed the pattern as the study did not involve any research involving the actual sea floor of the Bering Strait. As the climate cooled the ice sheets expanded and sea levels dropped - forming a land bridge. The flow of fresh water from the Pacific into the Atlantic via the Arctic Ocean was blocked and the Atlantic became much more salty. Ocean circulation in the Atlantic brought warm water northwards which warmed NE America and Greenland which reversed the advance of the ice sheets and eventually global sea levels rose once more to reopen the Bering Straits - and the cylce repeated itself over and over again. Actually, this is really quite a clever solution to the problem of sudden changes in climate that actually did occur in the Late Pleistocene era but it is less clear what evidence there might be that the straits were repeatedly above and below water. I assume that assumption was made at the beginning of the research.

Pardue University web site, www.purdue.edu January 20th ... Madagascar is thought to have been an island separated from Africa for some 120 million years - long before it's varied mammalian fauna had a chance of getting there. Therefore, rather than proposing the idea that Madagascar may have become an island sometime after the K/T boundary event when mammals began to thrive at the expense of reptiles, the possibilty that the ancestors of lemurs, flying foxes, and a variety of mongoose, all found nowhere else in the world, it is being suggested they rafted the 300 miles from Africa. The idea these animals evolved separately and in isolation appears to be feasible but the geology apparently is against this solution. The rafting idea has always been beset by the problem of currents and prevailing winds which flow away from Madagascar, to the S and SW, and not towards the island. The idea of a land bridge was proposed but there is no geological evidence of this. Now, computer simulations of past ocean currents by a Pardue scientist have shown that between 20 and 60 million years ago currents may well have flowed east from Africa towards Madagascar. It was also a region of tropical cyclones in the past capable of regularly washing trees and debris across the 300 mile wide divide - together with animals. The rafting idea is now back in vogue.