From: Antartica thread wrote:ancientd wrote:Certainly some have seen high voltage powerlines on live trees causing petrification very quickly.
* However, we still have to explain why flesh sometimes fossilized but most of the time did not.
The team—led by Peter Van Roy, a Yale postdoctoral associate, and Derek Briggs, the Frederick William Beinecke Professor of Geology & Geophysics and director of the Yale Peabody Museum of Natural History—uncovered more than 1,500 fossils of soft-bodied marine animals in newly discovered sites in southeastern Morocco during a field expedition last year. Many are complete fossils, and include sponges, annelid worms, mollusks and horseshoe crabs—in particular, a species similar to today’s horseshoe crab, which appeared some 30 million years earlier than previously known.
Fossilization occurred rapidly enough to be influenced by tissue composition and involved a diagenetic sequence: apatite calcite ± gypsum pyrite ± chalcopyrite galena.
The tyrannosaur of the minerals, this gold nugget in quartz weighs more than 70 ounces (2 kilograms).
By Becky Oskin, OurAmazingPlanet
Earthquakes have the Midas touch, a new study claims.
Water in faults vaporizes during an earthquake, depositing gold, according to a model published in the March 17 issue of the journal Nature Geoscience. The model provides a quantitative mechanism for the link between gold and quartz seen in many of the world's gold deposits, said Dion Weatherley, a geophysicist at the University of Queensland in Australia and lead author of the study.
When an earthquake strikes, it moves along a rupture in the ground — a fracture called a fault. Big faults can have many small fractures along their length, connected by jogs that appear as rectangular voids. Water often lubricates faults, filling in fractures and jogs.
About 6 miles (10 kilometers) below the surface, under incredible temperatures and pressures, the water carries high concentrations of carbon dioxide, silica and economically attractive elements like gold.
Shake, rattle and gold
During an earthquake, the fault jog suddenly opens wider. It's like pulling the lid off a pressure cooker: The water inside the void instantly vaporizes, flashing to steam and forcing silica, which forms the mineral quartz, and gold out of the fluids and onto nearby surfaces, suggest Weatherley and co-author Richard Henley, of the Australian National University in Canberra.
While scientists have long suspected that sudden pressure drops could account for the link between giant gold deposits and ancient faults, the study takes this idea to the extreme, said Jamie Wilkinson, a geochemist at Imperial College London in the United Kingdom, who was not involved in the study.
"To me, it seems pretty plausible. It's something that people would probably want to model either experimentally or numerically in a bit more detail to see if it would actually work," Wilkinson told OurAmazingPlanet.
Previously, scientists suspected fluids would effervesce, bubbling like an opened soda bottle, during earthquakes or other pressure changes. This would line underground pockets with gold. Others suggested minerals would simply accumulate slowly over time.
Weatherley said the amount of gold left behind after an earthquake is tiny, because underground fluids carry at most only one part per million of the precious element. But an earthquake zone like New Zealand's Alpine Fault, one of the world's fastest, could build a mineable deposit in 100,000 years, he said.
Surprisingly, the quartz doesn't even have time to crystallize, the study indicates. Instead, the mineral comes out of the fluid in the form of nanoparticles, perhaps even making a gel-like substance on the fracture walls. The quartz nanoparticles then crystallize over time. [Gold Quiz: From Nuggets to Flecks]
Even earthquakes smaller than magnitude 4.0, which may rattle nerves but rarely cause damage, can trigger flash vaporization, the study finds.
"Given that small-magnitude earthquakes are exceptionally frequent in fault systems, this process may be the primary driver for the formation of economic gold deposits," Weatherley told OurAmazingPlanet.
The hills have gold
Quartz-linked gold has sourced some famous deposits, such as the placer gold that sparked the 19th-century California and Klondike gold rushes. Both deposits had eroded from quartz veins upstream. Placer gold consists of particles, flakes and nuggets mixed in with sand and gravel in stream and river beds. Prospectors traced the gravels back to their sources, where hard-rock mining continues today.
But earthquakes aren't the only cataclysmic source of gold. Volcanoes and their underground plumbing are just as prolific, if not more so, at producing the precious metal. While Weatherley and Henley suggest that a similar process could take place under volcanoes, Wilkinson, who studies volcano-linked gold, said that's not the case.
"Beneath volcanoes, most of the gold is not precipitated in faults that are active during earthquakes," Wilkinson said. "It's a very different mechanism."
Understanding how gold forms helps companies prospect for new mines. "This new knowledge on gold-deposit formation mechanisms may assist future gold exploration efforts," Weatherley said.
In their quest for gold, humans have pulled more than 188,000 tons (171,000 metric tons) of the metal from the ground, exhausting easily accessed sources, according to the World Gold Council, an industry group.
These mineralised fibres of collagen are samples extracted from the ribs of an indeterminate dinosaur and analysed using a scanning electron microscope.
Scientists have discovered what appear to be red blood cells and collagen fibres in the fossilised remains of dinosaurs that lived 75 million years ago.
Traces of the soft tissues were found by accident when researchers at Imperial College in London analysed eight rather shabby fossils that had been dug up in Canada a century ago before finding their way to the Natural History Museum in London.
The finding suggests that scores of dinosaur fossils in museums around the world could retain soft tissues, and with it the answers to major questions about dinosaur physiology and evolution. More speculatively, it has made scientists ponder whether dinosaur DNA might also survive.
Most of the fossils the scientists studied were mere fragments and in very poor condition. They included a claw from a meat-eating therapod, perhaps a gorgosaurus, some limb and ankle bones from a duck-billed dinosaur, and a toe bone from triceratops-like animal.
This ungual claw from a theropod yielded structures which appear to be red blood cells. Photograph: Laurent Mekul
Intact soft tissue has been spotted in dinosaur fossils before, most famously by Mary Schweitzer at North Carolina State University, who in 2005 found flexible, transparent collagen in the fossilised leg of a Tyrannosaurus rex specimen.
What makes the latest discovery so remarkable is that the blood cells and collagen were found in specimens that the researchers themselves describe as “crap”. If soft tissue can survive in these fossils, then museum collections of more impressive remains could harbour troves of soft dinosaur tissue. Those could help unravel mysteries of dinosaur physiology and behaviour that have been impossible to crack with bony remains alone.
“It’s really difficult to get curators to allow you to snap bits off their fossils. The ones we tested are crap, very fragmentary, and they are not the sorts of fossils you’d expect to have soft tissue,” said Susannah Maidment, a paleontologist at Imperial.
The fossils are a smattering of pieces collected last century, probably directly from the ground, at the Dinosaur Park Formation in Alberta, Canada. To analyse the remains, the scientists broke tiny pieces off the fragments to expose fresh, uncontaminated surfaces inside.
Sergio Bertazzo, a materials scientist at Imperial, had been working on the build up of calcium in human blood vessels when he met Maidment and asked if he could study some fossils with an array of electron microscope techniques.
Months after the specimens arrived, Bertazzo began to look at thin sections of the fossils. He began with the therapod claw. “One morning, I turned on the microscope, increased the magnification, and thought ‘wait - that looks like blood!’,” he said.
Bertazzo suspected the blood was historic contamination: a curator or a collector had a cut when they handled the speciment. But Maidment suggested a check. Mammals are unusual among vertebrates in having red blood cells that lack a cell nucleus. If the fossil’s blood cells had nuclei, they could not be human. When they sliced through one of the cells to check, they saw what looked like a nucleus. “That ruled out someone bleeding on the sample,” said Maidment.
This video shows scanning electron micrographs being reconstructed into 3D shapes based on the serial sections taken of the red blood cell-like structures. Video: Bertazzo et al., Nature Communication
Another surprise was to come. Bertazzo was examining another fossil fragment, a piece of rib from some unidentified dinosaur, which had been sliced in two inside the microscope. He spotted bands of fibres, which further tests found to contain amino acids known that make up collagen, the protein-based material that forms the basis for skin and other soft tissues.
More work is needed to be sure the features are genuine blood cells and collagen. The scientists now hope to scour more fossils for soft tissues, and then work out what sorts of burial and environmental conditions are needed for their preservation.
“It may well be that this type of tissue is preserved far more commonly than we thought. It might even be the norm,” said Maidment, whose study appears in Nature Communications. “This is just the first step in this research.”
A detailed study of the soft tissues could unravel some of the long-standing mysteries of dinosaur evolution. The dinosaurs evolved from cold-blooded ancestors, but their modern descendants are warm-blooded birds. When did the transition occur? Red blood cells may hold the answer.
If collagen and red blood cells can survive for 75 million years, what about dinosaur DNA, bearing the genetic code to design, or potentially even resurrect, the beasts?
“We haven’t found any genetic material in our fossils, but generally in science, it is unwise to say never,” said Maidment. Bertazzo is hedging his bets too: “This opens up the possibility of loads of specimens that may have soft tissue preserved in them, but the problem with DNA is that even if you find it, it won’t be intact. It’s possible you could find fragments, but to find more than that? Who knows?”
Anjali Goswami, a paleontologist at University College London, said that if dinosaur soft tissues were found in many more fossils, it could have a transformative effect on research. “If we can expand the data we have on soft tissues, from fossils that are poorly preserved, that has real implications for our understanding of life in deep time,” she said.
If collagen and red blood cells can survive for 75 million years
The research, by Mars Science Laboratory Participating Scientists at The Open University and the University of Leicester, used the Mars Curiosity rover to explore Yellowknife Bay in Gale Crater on Mars, examining the mineralogy of veins that were paths for groundwater in mudstones.
The study suggests that the veins formed as the sediments from the ancient lake were buried, heated to about 50 degrees Celsius and corroded.
Professor John Bridges from the University of Leicester Department of Physics and Astronomy said: "The taste of this Martian groundwater would be rather unpleasant, with about 20 times the content of sulphate and sodium than bottled mineral water for instance!
"However as Dr Schwenzer from The Open University concludes, some microbes on Earth do like sulphur and iron rich fluids, because they can use those two elements to gain energy. Therefore, for the question of habitability at Gale Crater the taste of the water is very exciting news."
The researchers suggest that evaporation of ancient lakes in the Yellowknife Bay would have led to the formation of silica and sulphate-rich deposits.
Subsequent dissolution by groundwater of these deposits -- which the team predict are present in the Gale Crater sedimentary succession -- led to the formation of pure sulphate veins within the Yellowknife Bay mudstone.
The study predicts the original precipitate was likely gypsum, which dehydrated during the lake's burial.
The team compared the Gale Crater waters with fluids modelled for Martian meteorites shergottites, nakhlites and the ancient meteorite ALH 84001, as well as rocks analysed by the Mars Exploration rovers and with terrestrial ground and surface waters.
The aqueous solution present during sediment alteration associated with mineral vein formation at Gale Crater was found to be high in sodium, potassium and silicon, but had low magnesium, iron and aluminium concentrations and had a near neutral to alkaline pH level.
The mudstones with sulphate veins in the Gale Crater were also found to be close in composition to rocks in Watchet Bay in North Devon, highlighting a terrestrial analogue which supports the model of dissolution of a mixed silica and sulphate-rich shallow horizon to form pure sulphate veins.
Ashwin Vasavada, Curiosity Project Scientist from the NASA Jet Propulsion Laboratory said: "These result provide further evidence for the long and varied history of water in Gale Crater. Multiple generations of fluids, each with a unique chemistry, must have been present to account for what we find in the rock record today."
The above post is reprinted from materials provided by University of Leicester. Note: Materials may be edited for content and length.
allynh wrote:You don't need to have an external source of protons or neutrons to work the transmutation, just add energy to an existing molecule. Everything happens inside.
The quark structure of the proton. There are two up quarks in it and one down quark. The strong force is mediated by gluons (wavey). The strong force has three types of charges, the so-called red, green and the blue. Note that the choice of green for the down quark is arbitrary; the "color charge" is thought of as circulating among the three quarks. Credit: Arpad Horvath/Wikipedia
A large team made up of researchers from across the globe has repeated experiments conducted several years ago that showed a different radius for a proton when it was orbited by a muon as opposed to an electron—a finding dubbed the proton radius puzzle—using a deuterium nucleus this time and has found the same puzzle. In their paper published in the journal Science, the team describes the experiments they conducted, what they found and offer a few possible ideas to help dispel the notion that the puzzle indicates that there may be some problems with the Standard Model.
Scientists have been able to calculate the radius of a proton (0.88 ± 0.01 femtometers) for some time using the charge of the electron that orbits around it and doing so has helped confirm theories regarding the Standard Model. But, in trying to improve the accuracy of the measurement by using a negatively charged muon (which orbits closer to the proton), researchers at the Max Planck Institute back in 2010 found a different radius—one that was 7 deviations from what was considered the official value. This proton radius puzzle has had physicists scratching their heads ever since because it suggests there is an error in the Standard Model somewhere. Over the past six years various researchers have offered theories to solve the puzzle, most of which have involved ways to preserve the Standard Model, but to date, the puzzle still remains.
In this latest effort the researchers sought to gain more insight into the problem by adding another piece to the puzzle, a neutron, i.e. by using a deuterium nucleus. Their thinking was that the presence of the neutron would change the way that electrons and muons perceived the proton charge. They report that they found that the measurement they made of the radius of the proton was still different from that found with just an electron and proton, by approximately 7.5 sigma.
The results by the team offer no new explanations for the measurement discrepancies—it remains a puzzle, but they do offer some possible avenues for further investigation, e.g. ways to improve measurements and forcing muons to interact with the protons to see if there might be any evidence of an unknown force at work.
Explore further: Physicists confirm surprisingly small proton radius
More information: R. Pohl et al, Laser spectroscopy of muonic deuterium, Science (2016). DOI: 10.1126/science.aaf2468
The deuteron is the simplest compound nucleus, composed of one proton and one neutron. Deuteron properties such as the root-mean-square charge radius rd and the polarizability serve as important benchmarks for understanding the nuclear forces and structure. Muonic deuterium μd is the exotic atom formed by a deuteron and a negative muon μ–. We measured three 2S-2P transitions in μd and obtain rd = 2.12562(78) fm, which is 2.7 times more accurate but 7.5σ smaller than the CODATA-2010 value rd = 2.1424(21) fm. The μd value is also 3.5σ smaller than the rd value from electronic deuterium spectroscopy. The smaller rd, when combined with the electronic isotope shift, yields a "small" proton radius rp, similar to the one from muonic hydrogen, amplifying the proton radius puzzle.
Journal reference: Science
© 2016 Phys.org
The Wood Transformed into Iron Ore
During the set up f the iron pits in Orbissau in Bohemia, one discovered a former wood 15 to 20 feet under the ground, whose trees hat not fossilized on the normal way, but had been transformed into iron ore. Meanwhile these trunks have still had all branches and branches, and nobody could carry the slightest doubt that these have been formerly trees of a wood. One has also used these trunks of iron stone to melt it to iron, and has found them to be even more efficient, than the remaining iron stone that was surrounding it. Also here one is not able to get to another imagination than from an extensively long period that made such a change happen.
OLYMPUS experiment sheds light on structure of protons
A mystery concerning the structure of protons is a step closer to being solved, thanks to a seven-year experiment led by researchers at MIT. Credit: Christine Daniloff/MIT
A mystery concerning the structure of protons is a step closer to being solved, thanks to a seven-year experiment led by researchers at MIT.
For many years researchers have probed the structure of protons—subatomic particles with a positive charge—by bombarding them with electrons and examining the intensity of the scattered electrons at different angles.
In this way they have attempted to determine how the proton's electric charge and magnetization are distributed. These experiments had previously led researchers to assume that the electric and magnetic charge distributions are the same, and that one photon—an elementary particle of light—is exchanged when the protons interact with the bombarding electrons.
However, in the early 2000s, researchers began to carry out experiments using polarized electron beams, which measure electron-proton elastic scattering using the spin of the protons and electrons. These experiments revealed that the ratio of electric to magnetic charge distributions decreased dramatically with higher-energy interactions between the electrons and protons.
This led to the theory that not one but two photons were sometimes being exchanged during the interaction, causing the uneven charge distribution. What's more, the theory predicted that both of these particles would be so-called "hard," or high-energy photons.
In a bid to identify this "two-photon exchange," an international team led by researchers in the Laboratory for Nuclear Science at MIT carried out a seven-year experiment, known as OLYMPUS, at the German Electron Synchrotron (DESY) in Hamburg.
In a paper published this week in the journal Physical Review Letters, the researchers reveal the results of this experiment, which indicate that two photons are indeed exchanged during electron-proton interactions.
However, unlike the theoretical predictions, analysis of the OLYMPUS measurements suggests that, most of the time, only one of the photons has high energy, while the other must carry very little energy indeed, according to Richard Milner, a professor of physics and member of the Laboratory for Nuclear Science's Hadronic Physics Group, who led the experiment.
"We saw little if no evidence for a hard two-photon exchange," Milner says.
Having proposed the idea for the experiment in the late 2000s, the group was awarded funding in 2010.
The researchers had to disassemble the former BLAST spectrometer—a complex 125-cubic-meter-sized detector based at MIT—and transport it to Germany, where it was reassembled with some improvements. They then carried out the experiment over three months in 2012, before the particle accelerator at the laboratory was itself decommissioned and shut down at the end of that year.
The experiment, which was carried out at the same time as two others in the U.S. and Russia, involved bombarding the protons with both negatively charged electrons and positively charged positrons, and comparing the difference between the two interactions, according to Douglas Hasell, a principal research scientist in the Laboratory for Nuclear Science and the Hadronic Physics Group at MIT, and another of the paper's authors.
The process will produce a subtly different measurement depending on whether the protons are scattered by electrons or positrons, Hasell says. "If you see a difference (in the measurements), it would indicate that there is a two-photon effect that is significant."
The collisions were run for three months, and the resulting data took a further three years to analyze, Hasell says.
The difference between the theoretical and experimental results means further experiments may need to be carried out in the future, at even higher energies where the two-photon exchange effect is expected to be larger, Hasell says.
It may prove difficult to achieve the same level of precision reached in the OLYMPUS experiment, however.
"We ran the experiment for three months and produced very precise measurements," he says. "You would have to run for years to get the same level of precision, unless the performance (of the experiment) could be improved."
In the immediate future, the researchers plan to see how the theoretical physics community responds to the data, before deciding on their next step, Hasell says.
"It may be that they can make a small adjustment to a detail within their theoretical models to bring it all into agreement, and explain the data at both higher and lower energies," he says.
"Then it will be up to the experimentalists to check if that holds to be the case."
Explore further: Scientists mix matter and anti-matter to resolve decade-old proton puzzle
More information: Hard Two-Photon Contribution to Elastic Lepton-Proton Scattering Determined by the OLYMPUS Experiment Phys. Rev. Lett. 118, 092501 – Published 3 March 2017 journals.aps.org/prl/abstract/10.1103/PhysRevLett.118.092501
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