Geology news

Child of Krakatau

We've all hear of the devastating Krakatau eruption back in the 19th century when a jet of ash, stones, and smoke shot 12 miles into the sky - and killed 36,000 people. Now, Anat Krakatau, a small volcanic island that emerged from the ocean half a century after the 1883 volcanic eruption has rumbled into life - between Java and Sumatra. See https://wattsupwiththat.com/2018/07/19/worrying-child-of-krakatau-volcan...

Volcanic Twin

At https://phys.org/print450766148.html ... evidence of two volcanoes in Japan connected through a common subterranean magma source.

At https://wattsupwiththat.com/2018/07/16/sound-waves-reveal-huge-cache-of-... ... sound waves appear to show the existence of diamonds 100 miles below the surface of the earth.

Wine and Soils

I can remember attending a talk by a geologist some years ago now which concerned the geology of wine growing - and how soil and geology affected the flavours in the grapes. It was a fascinating talk and we all got to taste a glass of wine - which didn't actually prove anything either way. At https://phys.org/print449227859.html ... apparently Bloomberg has got hold of this idea and popularised the geology of wine - and various media wine writers are in on it as it adds a different dimension to the hype and mystique they can create around different wines (and their flavours).

Rocks and Nitrogen

Sent in by Jovan. At www.scientificamerican.com/article/mystery-of-earths-missing-nitrogen-so... ... mainstream considered nearly all the nitrogen ins soils came directly from the atmosphere, sequestered by microbes and dissolved in rain. Environmentalists, on the other hand, claim nitrogen mainly leaches from farm fields with an origin in nitrogenous fertilisers. However, it would seem there is another important source of nitrogen in soils - and therefore in run off into streams and rivers. Nitrogen that leaks out of rocks.

Modelling Geology

At https://phys.org/print447402256.html ... we are told it takes 120 million years for a slab of anicent sea floor to subduct to a sufficient distance into the Mantle where it can cause the core to cool. This, in turn, causes the liquid iron in the Earth's outer core to flow more vigorously - to produce a reversal of the Earth's magnetic field (courtesy of the modelling methodology). What this really says is that scientists do not like the idea of the earth's magnetic field reversing - or the core rotating faster than the outer shell (or crust).

Grand Canyon Geology

At https://phys.org/print447061881.html ... it is 50 years since the last formation was discovered and defined in the Grand Canyon but now geologists have been having a look at the Sixty Mile Formation - and their research is published in Nature Geoscience. It seems this particular piece of the Grand Canyon is somewhat younger than thought - ie it was generally labelled PreCambrian. The Sauk marine transgression event is dated between 600 and 500 million years ago and the formation is somewhat older.

Landscape Evolution

Scientists have struggled with a lingering question in geology. Why do the structures and elevations of some mountains continue to evolve long after the tectonic activity that formed them have ceased - see https://phys.org/print446805209.html ... and modelling has come to the rescue (or sort of). Sean Gallen from Colorado State University combined modelling with field research in a quite clever way to record the ebb and flow of activity in mountains in two national parks in the US. Activity clearly continued even after it was tectonically quiet.

Uluru

The geology of Ayers Rock is interesting - see for example www.ayersrockresort.com.au/uluru-and-kata-tjuta/ ... and https://en.wikipedia.org/wiki/Uluru ... but to get some really good pictures by a geologist go to https://earthly-musings.blogspot.com/2015/11/ayers-rock-uluru-and-olga-m... ... which has some fabulous views. This site also has a whole range of geological expeditions by the author and his friends, also with many pictures.

Peering Under the Ice and Assessing the Reef

Ice penetrating radar data in central Antartica has revealed valleys and mountains near the South Pole - see https://phys.org/print446450328.html .... and it seems the mountains prevent ice flowing from the main ice sheet towards the West Antarctic peninsular (and the sea).

Mantle Rocks

At https://phys.org/print446447917.html ... first seismic evidence for mantle exhumation at an ultra lsow spreading centre. Note the words ultra slow - which means barely negligible (or as we later find out, 2cm a year). The area referred to is the Canyon Trough off Grand Cayman island in the Caribbean. Exhumation is a reference to the regurgitation of mantle crust - a major plank of mainstream Plate Tectonics. Through gaps at plate boundaries material from the Earth's interior is thought to emerge, forming new sea floor.