Geology news

Not Written in Stone

Link provided by Robertus Maximus. It is the February 2018 newsletter of the AAPG (the Explorer). The piece is written by Keith James a consultant geologist and fellow of the Institute of Geophysics and Earth Sciences at Aberystywyth University in Wales. He has worked with Shell all over the world - and later with Conoco. The piece begins by saying that published Plate Tectonics (PT) teaching is complacent. It should adapt to emerging data, including multiple working hypotheses, and enable students to think.

Pileus

At http://spaceweather.com (March 2nd 2018) we have a fine image of saucer clouds over Brasilia ....

Red Beds

At https://sites.google.com/site/redbedsgeology/ ... red beds are composed of aeolian sands - sand waves deposited by flooding (or by tides). These also include sandstone rocks and can be seen on the Colorado Plateau - and various other places, dating from diverse geological periods. The oldest of them go back 1.5 billion years ago (the Proterozoic) and the youngest just 6 million years ago (the Miocene). They are  sand that has been reddened by finely dispersed iron oxides within clay minerals. They can actually be clay stones, silt stones, and conglomerates, and not just sandstone.

Mediterranean Mega Flood

This story is at https://phys.org/print438943372.html ... a study by an international team have found evidence of a mega flood during the Zanclean Period in which water from the Atlantic poured back into the Mediterranean basin and brought an end to the Messinian Salinity Crisis (5 million years ago). The study was led by Aaron Micallef of the University of Malta and is published in Scientific Reports journal (Feb 2018). The arguments revolve around bore hole data off Sicily, sediments buried in the sub surface characterised as chaotic.

Formation of Clays

At https://phys.org/print437125828.html ... in this instance, clay formation on the planet Mars. Temperature on Mars is well below freezing but it must once have been warmer if liquid water carved out features on the surface. Not only that but the water had to be warm enough for surface clays to form. The researchers opt for a series of short term warming episodes leading to temporary wet climates. All speculation of course.

Giant Earthquakes

At https://phys.org/print436523070.html ... giant earthquakes are not as random as thought. Analysis of sediment cores from lakes in Chile show that EQs reoccur at regular intervals. It is only when smaller EQs are added that the incidents show up randomly in time. A Chilean EQ in 1960 had a magnitude of 9.5 and produced a massive tsunami wave that pummeled the coastal regions and caused a wave that travelled right across the Pacific to kill 200 people in Japan. Strong EQs produce underwater landslides which are preserved in sedimentary layers.

Scottish Submerged Forest

This story is again interesting as far as changing sea levels and ocean configuration is concerned. At https://www.scotsman.com/lifestyle/archaeologists-survey-scotland-s-fore... ... archaeologists are surveying Scotland's submerged forests (rather, wooded regions under the waves). This seems to revolve around the Bay of Ireland in the Orkneys and Benbecula in the Outer Hebrides.

Vitiaz Arc

A study in the Proceedings of the Royal Society B (January 2018) have been looking at lizards in Australasia, Melanesia and Polynesia. We are told that when you scroll back the distribution of geckos, and their variants, they have a common ancestor that may go back to the Vitiaz Arc, a near continuous chain of islands that stretched across the Western Pacific 30 to 40 million years ago (during the Oligocene). Nowadays, the arc is represented by landforms such as the Philippines and a string of islands as far as Fiji.

oxydised iron

Diamonds with garnets can form at depths within Earth's Manetle. Earth scientists, it is said, made a discovery that 550km beneath the surface - oxydised iron. This is similar tro rust. It was found within garnets within diamonds - we are told. How does iron become rusty within the Mantle? One might point a finger at water in the Mantle - but not these guys. We know that iron exists as a metal in the core and Mantle - or so the mainstream songsheet assures us (and why not - a reasonable deduction).

The Big Brexit

I like the headline on this story - Britain's first departure from Europe (in this case a geological brexit) - go to www.nature.com/articles/doi:10.1038/ncomms15101 ... which concerns a paper attempting to pin down when the chalk ridge between Calais and Dover was first breached. It is assumed a large glacial lake had formed during or at the end of the Anglian Ice Age in what is now the North Sea basin. This tudy proposes the breach came in two stages.