Archives de catégorie : only geology

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.

Diamonds show Earth still capable of ‘superhot’ surprises

by Europlanet Media Centre, September 21, 2017 in ScienceDaily

Diamonds may be ‘forever’ but some may have formed more recently than geologists thought. A study of 26 diamonds, formed under extreme melting conditions in the Earth’s mantle, found two populations, one of which has geologically ‘young’ ages. The results show that certain volcanic events on Earth may still be able to create super-heated conditions previously thought to have only existed early in the planet’s history before it cooled. The findings may have implications for diamond prospecting.

See also here

Half-a-billion-year-old fossils shed light animal evolution on Earth

by University of Manchester, September 11, 2017 in ScienceDaily

The international team, including palaeontologist from The University of Manchester, found a new set of trace fossils left by some of the first ever organisms capable of active movement. Trace fossils are the tracks and burrows left by living organisms, not physical remains such as bones or body parts.

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Possible hominin footprints from the late Miocene (c. 5.7 Ma) of Crete?

by Gerard D. Gierlinski et al., August 31, 2017 in Proc.Geologist’sAssoc.

We describe late Miocene tetrapod footprints (tracks) from the Trachilos locality in western Crete (Greece), which show hominin-like characteristics. They occur in an emergent horizon within an otherwise marginal marine succession of Messinian age (latest Miocene), dated to approximately 5.7 Ma (million years), just prior to the Messinian Salinity Crisis.

A new estimate of biodiversity on Earth

by University of Chicago Press Journals, August 30, 2017 in ScienceDaily

To date, about 1.5 million species have been formally described in the scientific literature, most of them insects. Proportionally, bacteria comprise less than 1% of all described species.

In a new paper published in The Quarterly Review of Biology (September 2017), researchers from the University of Arizona have estimated that there are roughly 2 billion living species on Earth, over a thousand times more than the current number of described species.

The onset of widespread marine red beds and the evolution of ferruginous oceans

by Haijun Song et al., August 2017, in Nature

Banded iron formations were a prevalent feature of marine sedimentation ~3.8–1.8 billion years ago and they provide key evidence for ferruginous oceans. The disappearance of banded iron formations at ~1.8 billion years ago was traditionally taken as evidence for the demise of ferruginous oceans, but recent geochemical studies show that ferruginous conditions persisted throughout the later Precambrian, and were even a feature of Phanerozoic ocean anoxic events.

Earth history: How continents were recycled

by Ruhr-Universitaet-Bochum, August 22, 2017 in ScienceDaily

Researchers have used computer simulations to analyse how plate tectonics have evolved on Earth over the last three billion years. They show that tectonic processes have changed in the course of the time, and demonstrate how those changes contributed to the formation and destruction of continents. The model reconstructs how present-day continents, oceans and the atmosphere may have evolved.

See also here and here

Dino-killing asteroid could have thrust Earth into two years of darkness

by National Center for Atmospheric Research/University Corporation for Atmospheric Research, August 21, 2017 in ScienceDaily

Tremendous amounts of soot, lofted into the air from global wildfires following a massive asteroid strike 66 million years ago, would have plunged Earth into darkness for nearly two years, new research finds. This would have shut down photosynthesis, drastically cooled the planet, and contributed to the mass extinction that marked the end of the age of dinosaurs.

NASA’s Secret Plan to Save Earth From Super-Volcanoes… Seriously?

by David Middleton, August 18, 2017 in WUWT

If “the supervolcano threat is substantially greater than the asteroid or comet threat,” does this mean we can stop fretting about Gorebal Warming and the Sixth Mass Extinction?  Is NASA really moving on to actual threats to the planet?  Well, not threats to the planet… The planet has handled supervolcanoes, asteroids and comets quite well over its 4.5 billion year lifespan.