Archives par mot-clé : Geology

Unique diamond impurities indicate water deep in Earth’s mantle

by University of Nevada, March 9, 2018 in ScienceDaily

A UNLV scientist has discovered the first direct evidence that fluid water pockets may exist as far as 500 miles deep into the Earth’s mantle.

Groundbreaking research by UNLV geoscientist Oliver Tschauner and colleagues found diamonds pushed up from the Earth’s interior had traces of unique crystallized water called Ice-VII.

See alos here

New insight into how magma feeds volcanic eruptions

by University of Liverpool, February 2, 2018  in ScienceDaily

Researchers have provided new insights into how molten rock (magma) moves through the Earth’s crust to feed volcanic eruptions. Using laboratory experiments involving water, jelly and laser imaging, researchers were able to demonstrate how magma magma flows through the Earth’s crust to the surface through magma-filled cracks called dykes.

Plants colonized Earth 100 million years earlier than previously thought

by Bristol University, February 19, 2019 in ScienceDaily

A new study on the timescale of plant evolution has concluded that the first plants to colonize the Earth originated around 500 million years ago — 100 million years earlier than previously thought.

For the first four billion years of Earth’s history, our planet’s continents would have been devoid of all life except microbes.

Asteroid ‘time capsules’ may help explain how life started on Earth

by Georgia Institute of Technology, February 17, 2018 in ScienceDaily

In popular culture, asteroids play the role of apocalyptic threat, get blamed for wiping out the dinosaurs — and offer an extraterrestrial source for mineral mining. But for one researcher, asteroids play an entirely different role: that of time capsules showing what molecules originally existed in our solar system. Having that information gives scientists the starting point they need to reconstruct the complex pathway that got life started on Earth.

Marvel et al.’s new paper on estimating climate sensitivity from observations

by Nic Lewis, February 5, 2018 in ClimateAudit

Recently a new model-based paper on climate sensitivity was published by Kate Marvel, Gavin Schmidt (the head of NASA GISS) and others, titled ‘Internal variability and disequilibrium confound estimates of climate sensitivity from observations’. It appears to me that the novel part of its analysis is faulty, and that the part which isn’t faulty isn’t novel.

Study: Early humans witnessed global cooling, warming, and massive fires from comet debris impacts

by U. of Kansas, February 2, 2018 in WUWT, A. Watts

 On a ho-hum day some 12,800 years ago, the Earth had emerged from another ice age. Things were warming up, and the glaciers had retreated.

Out of nowhere, the sky was lit with fireballs. This was followed by shock waves.

Fires rushed across the landscape, and dust clogged the sky, cutting off the sunlight. As the climate rapidly cooled, plants died, food sources were snuffed out, and the glaciers advanced again. Ocean currents shifted, setting the climate into a colder, almost “ice age” state that lasted an additional thousand years.

Finally, the climate began to warm again, and people again emerged into a world with fewer large animals and a human culture in North America that left behind completely different kinds of spear points.

High geothermal heat flux in close proximity to the Northeast Greenland Ice Stream

by Rysgaard et al., January 22, 2018 in NatureSci.Reports

The Greenland ice sheet (GIS) is losing mass at an increasing rate due to surface melt and flow acceleration in outlet glaciers. Currently, there is a large disagreement between observed and simulated ice flow, which may arise from inaccurate parameterization of basal motion, subglacial hydrology or geothermal heat sources. Recently it was suggested that there may be a hidden heat source beneath GIS caused by a higher than expected geothermal heat flux (GHF) from the Earth’s interior.

What are, in fact, the grounds for concern about global warming?

by Javier, January 30, 2018 in AndyMay WUWT

Climate change is a reality attested by past records. Concerns about preparing and adapting for climate change are real. However, the idea that we can prevent climate change from happening is dangerous and might be anti-adaptive. Certain energy policies that might have no effect on climate change could make us less able to adapt.

Physics shows that adding carbon dioxide leads to warming under laboratory conditions. It is generally assumed that a doubling of CO2 should produce a direct forcing of 3.7 W/m2 [1], that translates to a warming of 1°C (by differentiating the Stefan-Boltzmann equation) to 1.2°C (by models taking into account latitude and season). But that is a maximum value valid only if total energy outflow is the same as radiative outflow. As there is also conduction, convection, and evaporation, the final warming without feedbacks is probably less. Then we have the problem of feedbacks that we don’t know and cannot properly measure. For some of the feedbacks, like cloud cover we don’t even know the sign of their contribution. And they are huge, a 1% change in albedo has a radiative effect of 3.4 W/m2 [2], almost equivalent to a full doubling of CO2.

L’ Empire des Métaux Rares

by Edouard Guigue, 13 janvier 2018

Que sont les métaux rares ? Des ressources peu connues mais essentielles au fonctionnement de l’espace mondialisé. Insérées au cœur de tout appareil électronique, sans elles aucune de nos technologies numériques n’existerait. Composant également la plupart de nos technologies vertes (éoliennes, panneaux solaires ou voitures électriques), leurs modes de production laissent toutefois perplexe sur leur capacité à s’établir comme alternatives durables aux énergies fossiles. La pollution ne serait pas réduite mais simplement délocalisée… essentiellement en Chine où 95% des terres rares sont produites. Un chiffre qui par ailleurs devrait nous alarmer sur la situation de dépendance à la Chine dans laquelle le reste du monde  -dont l’Europe- se trouve depuis les années 1980. Guillaume Pitron nous présente une enquête de six ans, dont les résultats sont à retrouver dans son livre La guerre des métaux rares.

Sensitivity to lunar cycles prior to the 2007 eruption of Ruapehu volcano

by T. Girona, C. Huber, C. Caudron,  January 24, 2018 in Nature

A long-standing question in Earth Science is the extent to which seismic and volcanic activity can be regulated by tidal stresses, a repeatable and predictable external excitation induced by the Moon-Sun gravitational force. Fortnightly tides, a ~14-day amplitude modulation of the daily tidal stresses that is associated to lunar cycles, have been suggested to affect volcano dynamics. However, previous studies found contradictory results and remain mostly inconclusive. Here we study how fortnightly tides have affected Ruapehu volcano (New Zealand) from 2004 to 2016 by analysing the rolling correlation between lunar cycles and seismic amplitude recorded close to the crater. (…)

Groundbreaking AGW-Undermining Study: Greenland’s Warming, Ice Loss Due To Geothermal Heat

by K. Richard, January 24, 2018 in NoTricksZone

A few years ago, 10 glaciologists publishing in the journal Nature Geoscience asserted that “large parts of the north-central Greenland ice sheet are melting from below” due to high geothermal heat flux forcing (Rogozhina et al., 2016).

In a new paper published in Scientific Reports, 4 more glaciologists (Rysgaardet al., 2018) report that “hot vents” (or hot springs) of geothermally-heated water underneath the Greenland ice sheet can explain localized rising temperatures and glacial melting.

Worse than we thought’ – climate models underestimate future polar warming

by  FLORIDA MUSEUM OF NATURAL HISTORY,  January 23, 2018, in WUWT, A. Watts

The researchers published their findings this week in the Proceedings of the National Academy of Sciences.

Scientists frequently look to the Eocene to understand how the Earth responds to higher levels of carbon dioxide. During the Eocene, the concentration of carbon dioxide in the atmosphere was more than 560 parts per million, at least twice preindustrial levels, and the epoch kicked off with a global average temperature more than 8 degrees Celsius – about 14 degrees Fahrenheit – warmer than today, gradually cooling over the next 22 million years. These characteristics make the Eocene a good period on which to test our understanding of the climate system, said Laura Cotton, study co-author and curator of micropaleontology at the Florida Museum of Natural History.

Earth’s Rotation Is Mysteriously Slowing Down: Experts Predict Uptick In 2018 Earthquakes

by Tevor Nace, November 20, 2017 in WhoaScience

Scientists have found strong evidence that 2018 will see a big uptick in the number of large earthquakes globally. Earth’s rotation, as with many things, is cyclical, slowing down by a few milliseconds per day then speeding up again.

You and I will never notice this very slight variation in the rotational speed of Earth. However, we will certainly notice the result, an increase in the number of severe earthquakes.

Geophysicists are able to measure the rotational speed of Earth extremely precisely, calculating slight variations on the order of milliseconds. Now, scientists believe a slowdown of the Earth’s rotation is the link to an observed cyclical increase in earthquakes.

Seafloor Volcano Pulses May Alter Climate

by Columbia University, February 5, 2015

Vast ranges of volcanoes hidden under the oceans are presumed by scientists to be the gentle giants of the planet, oozing lava at slow, steady rates along mid-ocean ridges. But a new study shows that they flare up on strikingly regular cycles, ranging from two weeks to 100,000 years—and, that they erupt almost exclusively during the first six months of each year. The pulses—apparently tied to short- and long-term changes in earth’s orbit, and to sea levels–may help trigger natural climate swings. Scientists have already speculated that volcanic cycles on land emitting large amounts of carbon dioxide might influence climate; but up to now there was no evidence from submarine volcanoes. The findings suggest that models of earth’s natural climate dynamics, and by extension human-influenced climate change, may have to be adjusted

Further proof El Ninos are fueled by deep-sea geological heat flow

by Janes E Kamis, January, 27 in CliateChangeDispatch

The 2014-2017 El Nino “warm blob” was likely created, maintained, and partially recharged on two separate occasions by massive pulses of super-heated and chemically charged seawater from deep-sea geological features in the western North Pacific Ocean. This strongly supports the theory all El Ninos are naturally occurring and geological in origin. Climate change / global warming had nothing to do with generating, rewarming, intensifying, or increasing the frequency of the 2014-2017 El Nino or any previous El Nino.

If proven correct, this would revolutionize climatology and key aspects of many interrelated sciences such as oceanography, marine biology, glaciology, biogeochemistry, and most importantly meteorology. Information supporting a geological origin of El Ninos is diverse, reliable, and can be placed into five general categories as follows: (…)

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