Volcanoes

1 Jul 2020

William sent in a link to www.yahoo.com/news/study-finds-asteroid-impact-not-190949370.html ...but see also https://phys.org/news/2020-06-asteroid-impact-volcanoes-earth-uninhabita... ... this concerns the conflict of interest between geologists over the K/T event. Was it the asteroid that killed off the dinosaurs or was it volcanism. This new study favours the asteroid. What is not considered in the study is the likelihood that the asteroid impact gave rise to the volcanism which means, contrary to the dating of the sediments laid down, both were contemporary and arguing over which was the worst is pointless. Also, modelling was used, and nobody got their feet wet. However, having said that we may note that getting out in the field in the Yucatan or at the Deccan Traps in India, would not have yielded any useful information as long as the sediments are being dated over millions and millions of years. Computer modelling has a role to play and is increasingly used by scientists. The elephant in the room concerns what is fed into the computers.

This study claims that only an asteroid strike would have created the conditions that were unfavourable to dinosaurs across the world. They also claim to show that massive volcanism could have helped life to recover. Something of a paradox there as erupting volcanoes are capable of throwing lots of dust and gases into the atmosphere, somewhat akin to an asteroid strike. The computer modelling excercise seems to have compared the two and decided one effect was more severe than the other - and it probably was (if they occurred in isolation). Geologists would not of course think in terms of contemporeignty and would not question the idea the sediments were laid down over a long period of time, even though they have a modern parallel, the eruption of the Mount St Helens volcano. Catastrophists think outside the box, but nobody, as far as I know, is going to the extreme of reducing the time scales before and after the K/T boundary event. Don't expect any change any time soon which means more and more studies such as this one. Basically, they are saying the asteroid strike caused a prolonged nuclear winter scenario even though volcanic eruptions also create nuclear winter scenarios (but on a reduced scale).

At https://phys.org/news/2020-06-historic-reveal-salt-marshes-future.html ... environmentalists love wetland environments. In a paper published in Nature Sustainability we have all the climate change tick boxes clicking away. Apparently, wetlands are now valuable natural defences against storm surges, protecting not just the sea shore but the dykes built by the likes of the Dutch. Why did they build the dykes then, we may wonder, if it was not because storms breached salt marshes and flooded farms and towns. Wetlands are home to lots of wildlife, most of which can fly away come a big storm - but not everything. They are drowned or dig into a burrow or find a hidey hole somewhere. As an example they use the 1953 North Sea flood which involved a storm surge and a lot of rain and wind. They also refer to an 18th century sea flood as well. It seems salt marsh can stop dykes being overwhelmed and it would seem a very good idea to combine salt marsh on the sea ward side of dyke systems as a sort of brake on the momentum of storms and sea surges. Wetlands are of course watery places with lots of clay and silt as a geological feature. Is there enough space to create such salt marsh where it does not exist at the moment. Environmental ideas are not always practicable or involve a lot of expense for negligible benefit. It may be tried in a few places but unless there is a lot of money available not much notice will be made.

At https://phys.org/news/2020-06-volcanoes-deep-sea.html ... at this link we are back to volcanoes. Deep sea volcanoes on the ocean floor, and sea mounts. A diving robot was sent down 1000m NW of New Zealand to a seamount volcano that erupted in 2012. The idea was to look at how the volcano adapted to a watery environment and what it left behind. At the time it created a floating island of pumice. The robot found evidence of lots of volcanic ash on the sea bed, on and around the sea mount, estimated to be 100 cubic metres. The robot also took samples from the sea floor. Interesting results. Naturally, under the sea volcanoes don't appear in climate models - or in estimates of co2 in oceans.