Archives de catégorie : only geology

Unique underwater stalactites

by Heidelberg University, November 24, 2017 in ScienceDaily

In recent years, researchers have identified a small group of stalactites that appear to have calcified underwater instead of in a dry cave. The Hells Bells in the El Zapote cave near Puerto Morelos on the Yucatán Peninsula are just such formations. Scientists have recently investigated how these bell-shaped, meter-long formations developed, assisted by bacteria and algae.

Water cooling for the Earth’s crust

by Helmholtz Centre for Ocean Research Kiel (GEOMAR), November 21, 2017 in ScienceDaily

How deep can seawater penetrate through cracks and fissures into the seafloor? By applying a new analysis method, an international team of researchers has now discovered that the water can penetrate to depths of more than 10 kilometers below the seafloor. This result suggests a stronger cooling effect on the hot mantle.

Credit : GEOMAR

See also here

Doggerland – The Europe That Was

by National Geography, 2017

The British Isles were once neither British nor isles

Things aren’t always what they seem on the surface. Looking at the area between mainland Europe and the eastern coast of Great Britain, you probably wouldn’t guess it had been anything other than a great expanse of ocean water. But roughly 12,000 years ago, as the last major ice age was reaching its end, the area was very different. Instead of the North Sea, the area was a series of gently sloping hills, marshland, heavily wooded valleys, and swampy lagoons: Doggerland.

The effect of giant lateral collapses on magma pathways and the location of volcanism

by F. Maccaferri et al., October 23, 2017 in NatureCommunication

Open Article

The results reveal that a lateral collapse can trigger a significant deflection of deep magma pathways in the crust, favouring the formation of a new eruptive centre within the collapse embayment. Our results have implications for the long-term evolution of intraplate volcanic ocean islands.

Global nickel anomaly links Siberian Traps eruptions and the latest Permian mass extinction

by Michael R. Rampino et al., October 2017, in Nature

Anomalous peaks of nickel abundance have been reported in Permian-Triassic boundary sections in China, Israel, Eastern Europe, Spitzbergen, and the Austrian Carnic Alps. New solution ICP-MS results of enhanced nickel from P-T boundary sections in Hungary, Japan, and Spiti, India suggest that the nickel anomalies at the end of the Permian were a worldwide phenomenon.

See also here and here

Did life on Earth start due to meteorites splashing into warm little ponds?

by McMaster University, October 2, 2017 in ScinceDaily

Life on Earth began somewhere between 3.7 and 4.5 billion years ago, after meteorites splashed down and leached essential elements into warm little ponds, say scientists. Their calculations suggest that wet and dry cycles bonded basic molecular building blocks in the ponds’ nutrient-rich broth into self-replicating RNA molecules that constituted the first genetic code for life on the planet.

Lost continent of Zealandia: Scientists return from expedition to sunken land

by National Science Foundation, September 26, 2017  in ScienceDaily

Expedition co-chief scientist Rupert Sutherland of Victoria University of Wellington in New Zealand said researchers had believed that Zealandia was submerged when it separated from Australia and Antarctica about 80 million years ago.

Big geographic changes across northern Zealandia, which is about the same size as India, have implications for understanding questions such as how plants and animals dispersed and evolved in the South Pacific.

Submarine Volcanoes etc.

The most productive volcanic systems on Earth are hidden under an average of 8,500 feet (2,600 m) of water. Beneath the oceans a global system of mid-ocean ridges produces an estimated 75% of the annual output of magma. An estimated 0.7 cubic miles (3 cubic kilometers) of lava is erupted. The magma and lava create the edges of new oceanic plates and supply heat and chemicals to some of the Earth’s most unusual and rare ecosystems.