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A medley of Antarctica, the ITCZ, and geology off the coast of Spain

27 May 2013

At http://phys.org/print288877504.html … Prior to the ice cap Antarctica had a tropical, or a near tropical environment – or was it just temperate? – which is how this piece begins. Not such a good start perhaps and the headline is even more dramatic – the ice cap arrived 33 million years ago. In the Oligocene. However, when we enter the nuts and bolts of the piece we might put the above down to a keen PR piece of prose for the purpose of a press release as it doesn't appear to actually involve dating the ice cap at all. What it is about is the change in plankton species in the seas surrounding Antartica. Formerly, when the climate was more agreeable (whatever it was, tropical or temperate) there were many species of plankton. Once the ice cap arrived plankton were forced to adapt and this led to a small number of surviving species – and these have continued into the modern world. The article is in Science magazine which may account for the over the top headline but concerns an ocean drilling programmed expedition that has been looking at palaeoclimate via the plankton preserved in sediments from the depths. The ice sediments come from different depths. It did not involve a continuous sediment plug. However, the research does illustrate that once it formed the ice cap has remained at the Antarctic. It may have shrunk on occasion but the plankton in each sediment sample shows quite clearly that the ice has consistently been at the South Pole for a very long time.

PS … this is not the case for the West Antarctic ice sheet (on the peninsular which sticks upwards, pointing towards the tip of S America).

At http://phys.org/print288894282.html … we have the ITCZ (Intertropic Convergence Zone) or the tropical rainfall belt that makes the equatorial forest a wet and green environment, as wide as that belt of forest and situated below the drier zones of first the savannah grassland belt, and secondly the very dry desert belt, and topped by the temperate forest belt (with agreeable rainfall levels) and above this the Polar Front or Jet Stream with cooler weather to the north. Hence, this year we have the Jet Stream above Europe and Asia somewhat south of it's normal situation which has squeezed the drier zones and likewise impacted on the equatorial region. This has happened throughout history. In the Ice Ages, or the Younger Dryas, the Polar Front was at a latitude coinciding with Spain and Portugal. In the warm Mid Holocene period the Polar Front was high up in northern Europe. In other words, it is common practise for the ITCZ to change position – nothing out of the ordinary. Apparently, global warming models are telling the scientists who take these things seriously that the ITCZ will move north – contrary to what is actually happening in the real world.

Meanwhile, at http://phys.org/print288864932.html … a team of scientists have embarked on a shipboard expedition to study how the crust of the Earth was pulled apart in an area off the coast of Spain. University of Southampton geophysicists are involved in the project. The target is the Deep Galicia Basin which lies to the west of northern Spain. Going back 250 million years ago Spain was connected to Newfoundland but at some point afterwards the two regions were driven apart in association with volcanism and tectonic activity, the magma forming new ocean crust. The research will drop 78 seismic detectors overboard and use sound waves to image structures on the sea floor. The idea is to collect information on faults and continental blocks. One particular fault line will be of primary interst. Ongoing information about the project as it happens day by day is available at http://galicia3d.blogspot.co.uk

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