World's Oldest Blue Bird Found via Fossil Feathers

<div dir="ltr" style="text-align: left;" trbidi="on"> <table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody> <tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-_BLK7yye7Ac/XRYuba1uEGI/AAAAAAAARLg/LB_lUYuJmS0OwIG_pBXnd1reI1ytazvxACLcBGAs/s1600/World%2527s%2BOldest%2BBlue%2BBird%2BFound%2Bvia%2BFossil%2BFeathers%2B%25281%2529.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="World's Oldest Blue Bird Found via Fossil Feathers" border="0" data-original-height="707" data-original-width="1181" height="382" src="https://1.bp.blogspot.com/-_BLK7yye7Ac/XRYuba1uEGI/AAAAAAAARLg/LB_lUYuJmS0OwIG_pBXnd1reI1ytazvxACLcBGAs/s640/World%2527s%2BOldest%2BBlue%2BBird%2BFound%2Bvia%2BFossil%2BFeathers%2B%25281%2529.jpg" title="" width="640" /></a></td></tr> <tr><td class="tr-caption" style="text-align: center;">Eocoracias brachyptera fossil sample. (Sven Traenkner/Senckenberg Research Institute and Nature Museum)</td></tr> </tbody></table> <br /> <span style="font-family: "georgia" , "times new roman" , serif;">For the first time, scientists have found a blue-feathered bird in the fossil record, thanks to a new discovery that lets us tell which fossilised pigments are, in fact, blue.</span><br /> <br /> Examining fossilised pigments, scientists from the University of Bristol have uncovered new insights into blue colour tones in prehistoric birds.<br /> <br /> For some time, paleontologists have known that melanin pigment can preserve in fossils and have been able to reconstruct fossil colour patterns.<br /> <br /> Melanin pigment gives black, reddish brown and grey colours to birds and is involved in creating bright iridescent sheens in bird feathers.<br /> <br /> This can be observed by studying the melanin packages called melanosomes, which are shaped like little cylindrical objects less than one-thousandth of a millimetre and vary in shape from sausage shapes to little meatballs.<br /> <br /> Now researchers from the University of Bristol, led by Frane Barbarovic who is currently at the University of Sheffield, have shown that blue feather melanosomes are highly distinct from melanosomes that are from feathers expressing black, reddish-brown, brown and iridescent, but overlap significantly with some grey feather melanosomes.<br /> <div style="margin: 0px auto; width: 100%;"> <script async="" src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script><br /> <ins class="adsbygoogle" data-ad-client="ca-pub-1021498709184325" data-ad-format="fluid" data-ad-layout="in-article" data-ad-slot="6157425841" style="display: block; text-align: center;"></ins><br /> <script> (adsbygoogle = window.adsbygoogle || []).push({}); </script><br /></div> By looking at plumage colourations of modern representatives of fossil specimen and reconstructing which colour was the most likely present in the fossil specimen, they were able to discriminate between melanosomes significant for grey and blue colour, leading to the reconstruction of prehistoric Eocoracias brachyptera as a predominantly blue bird.<br /> <br /> Frane Barbarovic said: "We have discovered that melanosomes in blue feathers have a distinct range in size from most of colour categories and we can, therefore, constrain which fossils may have been blue originally.<br /> <br /> "The overlap with grey colour may suggest some common mechanism in how melanosomes are involved in making grey colouration and how these structural blue colours are formed.<br /> <br /> "Based on these results in our publication we have also hypothesized potential evolutionary transition between blue and grey colour."<br /> <br /> The research team now need to understand which birds are more likely to be blue based on their ecologies and modes of life. The blue colour is common in nature, but the ecology of this colour and its function in the life of birds is still elusive.<br /> <br /> Frane Barbarovic added: "We also need to understand how grey colour is made. This is made in a very different way in birds than it is in mammals. We believe it is related to how the melanosome shape can result in a kind of self-assembling process in the feather and the surface tension of the melanosomes pull them into certain configurations inside a feather as it forms."<br /> <br /> However, besides iridescent colours, which is structural, birds also make non-iridescent structural colours.<br /> <br /> Those are, for example, blue colour tones in parrots and kingfishers. Until now, it was not known if such colours could be discovered in fossils.<br /> <br /> This blue structural colour is created by the dense arrangement of cavities inside feathers, which scatters the blue light. Underneath is a layer of melanin that absorbs unscattered light.<br /> <br /> Paleontologists have shown that the feather itself, which is made of keratin, does not fossilise while the melanin does. Therefore, if a blue feather fossilised, the dark pigment may be the only surviving feature and the feather may be interpreted as black or brown.<br /> <br /> <br /> The above story is based on <a href="https://royalsocietypublishing.org/doi/10.1098/rsif.2018.0921" rel="nofollow" target="_blank">materials </a>provided by University of Bristol.</div>

World's Oldest Blue Bird Found via Fossil Feathers

Eocoracias brachyptera fossil sample. (Sven Traenkner/Senckenberg Research Institute and Nature Museum) For the first time, scientists...

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Researchers Discover Giant Freshwater Aquifer off U.S. East Coast

<div dir="ltr" style="text-align: left;" trbidi="on"> <table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody> <tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-CYyZg9ce398/XRD3pfJMcYI/AAAAAAAARK8/KQAMu6-IX-MskJoWV2MJHmuNaeql8d2ZgCLcBGAs/s1600/A%2BMassive%2BReservoir%2BOf%2BFreshwater%2BWas%2BJust%2BDiscovered%2BOffshore%2BNew%2BEngland.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="Researchers Discover Giant Freshwater Aquifer off U.S. East Coast" border="0" data-original-height="820" data-original-width="1198" height="438" src="https://1.bp.blogspot.com/-CYyZg9ce398/XRD3pfJMcYI/AAAAAAAARK8/KQAMu6-IX-MskJoWV2MJHmuNaeql8d2ZgCLcBGAs/s640/A%2BMassive%2BReservoir%2BOf%2BFreshwater%2BWas%2BJust%2BDiscovered%2BOffshore%2BNew%2BEngland.jpg" title="" width="640" /></a></td></tr> <tr><td class="tr-caption" style="text-align: center;">Scientists have mapped a huge aquifer off the US Northeast (hatched area). Solid yellow or white lines with triangles show ship tracks. Dotted white line near shore shows edge of the glacial ice sheet that melted about 15,000 years ago. Further out, dark blue, the continental shelf drops off into the Atlantic abyss. Credit: Gustafson et al., Scientific Reports </td></tr> </tbody></table> <br /> <br /> <span style="font-family: "georgia" , "times new roman" , serif;">Underneath the salty waters of the North Atlantic ocean, geologists have discovered a giant aquifer of freshwater, hidden from view just off the US coast.</span><br /> <br /> In a new survey of the sub-seafloor off the U.S. Northeast coast, scientists have made a surprising discovery: a gigantic aquifer of relatively fresh water trapped in porous sediments lying below the salty ocean. It appears to be the largest such formation yet found in the world.<br /> <br /> The aquifer stretches from the shore at least from Massachusetts to New Jersey, extending more or less continuously out about 50 miles to the edge of the continental shelf. If found on the surface, it would create a lake covering some 15,000 square miles. The study suggests that such aquifers probably lie off many other coasts worldwide, and could provide desperately needed water for arid areas that are now in danger of running out.<br /> <br /> The researchers employed innovative measurements of electromagnetic waves to map the water, which remained invisible to other technologies. "We knew there was fresh water down there in isolated places, but we did not know the extent or geometry," said lead author Chloe Gustafson, a Ph.D. candidate at Columbia University's Lamont-Doherty Earth Observatory. "It could turn out to be an important resource in other parts of the world." The study appears this week in the journal Scientific Reports.<br /> <div style="margin: 0px auto; width: 100%;"> <script async="" src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script><br /> <ins class="adsbygoogle" data-ad-client="ca-pub-1021498709184325" data-ad-format="fluid" data-ad-layout="in-article" data-ad-slot="6157425841" style="display: block; text-align: center;"></ins><br /> <script> (adsbygoogle = window.adsbygoogle || []).push({}); </script><br /></div> The first hints of the aquifer came in the 1970s, when companies drilled off the coastline for oil, but sometimes instead hit fresh water. Drill holes are just pinpricks in the seafloor, and scientists debated whether the water deposits were just isolated pockets or something bigger. Starting about 20 years ago, study coauthor Kerry Key, now a Lamont-Doherty geophysicist, helped oil companies develop techniques to use electromagnetic imaging of the sub-seafloor to look for oil.<br /> <br /> More recently, Key decided to see if some form of the technology could also be used also to find fresh-water deposits. In 2015, he and Rob L. Evans of Woods Hole Oceanographic Institution spent 10 days on the Lamont-Doherty research vessel Marcus G. Langseth making measurements off southern New Jersey and the Massachusetts island of Martha's Vineyard, where scattered drill holes had hit fresh-water-rich sediments.<br /> <br /> They dropped receivers to the seafloor to measure electromagnetic fields below, and the degree to which natural disruptions such as solar winds and lightning strikes resonated through them. An apparatus towed behind the ship also emitted artificial electromagnetic pulses and recorded the same type of reactions from the subseafloor.<br /> <br /> Both methods work in a simple way: salt water is a better conductor of electromagnetic waves than fresh water, so the freshwater stood out as a band of low conductance. Analyses indicated that the deposits are not scattered; they are more or less continuous, starting at the shoreline and extending far out within the shallow continental shelf—in some cases, as far as 75 miles. For the most part, they begin at around 600 feet below the ocean floor, and bottom out at about 1,200 feet.<br /> <br /> The consistency of the data from both study areas allowed to the researchers to infer with a high degree of confidence that fresh water sediments continuously span not just New Jersey and much of Massachusetts, but the intervening coasts of Rhode Island, Connecticut and New York. They estimate that the region holds at least 670 cubic miles of fresh water. If future research shows the aquifer extends further north and south, it would rival the great Ogallala Aquifer, which supplies vital groundwater to eight Great Plains states, from South Dakota to Texas.<br /> <div style="margin: 0px auto; width: 100%;"> <script async="" src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script><br /> <ins class="adsbygoogle" data-ad-client="ca-pub-1021498709184325" data-ad-format="fluid" data-ad-layout="in-article" data-ad-slot="6157425841" style="display: block; text-align: center;"></ins><br /> <script> (adsbygoogle = window.adsbygoogle || []).push({}); </script><br /></div> The water probably got under the seabed in one of two different ways, say the researchers. Some 15,000 to 20,000 years ago, toward the end of the last glacial age, much of the world's water was locked up in mile-deep ice; in North America, it extended through what is now northern New Jersey, Long Island and the New England coast. Sea levels were much lower, exposing much of what is now the underwater U.S. continental shelf. When the ice melted, sediments formed huge river deltas on top of the shelf, and fresh water got trapped there in scattered pockets. Later, sea levels rose. Up to now, the trapping of such "fossil" water has been the common explanation for any fresh water found under the ocean.<br /> <br /> But the researchers say the new findings indicate that the aquifer is also being fed by modern subterranean runoff from the land. As water from rainfall and water bodies percolates through onshore sediments, it is likely pumped seaward by the rising and falling pressure of tides, said Key. He likened this to a person pressing up and down on a sponge to suck in water from the sponge's sides.<br /> <br /> Also, the aquifer is generally freshest near the shore, and saltier the farther out you go, suggesting that it mixes gradually with ocean water over time. Terrestrial fresh water usually contains less than 1 part per thousand salt, and this is about the value found undersea near land. By the time the aquifer reaches its outer edges, it rises to 15 parts per thousand. (Typical seawater is 35 parts per thousand.)<br /> <br /> If water from the outer parts of the aquifer were to be withdrawn, it would have to be desalinated for most uses, but the cost would be much less than processing seawater, said Key. "We probably don't need to do that in this region, but if we can show there are large aquifers in other regions, that might potentially represent a resource" in places like southern California, Australia, the Mideast or Saharan Africa, he said. His group hopes to expand its surveys.<br /> <br /> <br /> <u><i><span style="font-family: "trebuchet ms" , sans-serif;">The above story is based on <a href="https://blogs.ei.columbia.edu/2019/06/20/undersea-freshwater-aquifer-northeast/" rel="nofollow" target="_blank">Materials</a> provided by <a href="https://www.earth.columbia.edu/" rel="nofollow" target="_blank">Earth Institute at Columbia University</a>. Original written by Kevin Krajick. </span></i></u><span style="background-color: white; color: #333333; display: inline; float: none; font-family: "helvetica neue" , "helvetica" , "arial" , sans-serif; font-size: 14px; font-style: normal; font-weight: 400; letter-spacing: normal; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;"><br /> </span></div>

Researchers Discover Giant Freshwater Aquifer off U.S. East Coast

Scientists have mapped a huge aquifer off the US Northeast (hatched area). Solid yellow or white lines with triangles show ship tracks. D...

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What is Hopper Crystal?

<div dir="ltr" style="text-align: left;" trbidi="on"> <table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody> <tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-CAqYFOZyU58/XQzyp3iEVSI/AAAAAAAARKI/tIOs5Ufqv_kcEJAHPu8FXUZD8U64rJJNgCLcBGAs/s1600/What%2Bis%2BHopper%2BCrystal.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="What is Hopper Crystal?" border="0" data-original-height="881" data-original-width="1200" height="468" src="https://1.bp.blogspot.com/-CAqYFOZyU58/XQzyp3iEVSI/AAAAAAAARKI/tIOs5Ufqv_kcEJAHPu8FXUZD8U64rJJNgCLcBGAs/s640/What%2Bis%2BHopper%2BCrystal.jpg" title="" width="640" /></a></td></tr> <tr><td class="tr-caption" style="text-align: center;">Hopper Halite crystal from Searles Lake, Trona, California. Photo: crystalminer</td></tr> </tbody></table> <h4 style="text-align: left;"> <span style="font-family: "georgia" , "times new roman" , serif;">A hopper crystal is a form of crystal, defined by its "hoppered" shape. </span></h4> This form appears, when a crystal grows faster at the edges of each face, than at the centre. This is due to a higher electrical attraction along the edges of the crystal, so they draw the mineral molecules stronger than the interior sections.<br /> <br /> The edges of hoppered crystals are fully developed, but the interior spaces are not filled in. This results in what appears to be a hollowed out step lattice formation, as if someone had removed interior sections of the individual crystals. In fact, the "removed" sections never filled in, because the crystal was growing so rapidly that there was not enough time (or material) to fill in the gaps.<br /> <br /> The interior edges of a hoppered crystal still show the crystal form characteristic to the specific mineral, and so appear to be a series of smaller and smaller stepped down miniature versions of the original crystal.<br /> <div style="margin: 0px auto; width: 100%;"> <script async="" src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script><br /> <ins class="adsbygoogle" data-ad-client="ca-pub-1021498709184325" data-ad-format="fluid" data-ad-layout="in-article" data-ad-slot="6157425841" style="display: block; text-align: center;"></ins><br /> <script> (adsbygoogle = window.adsbygoogle || []).push({}); </script><br /></div> Hoppering occurs when electrical attraction is higher along the edges of the crystal; this causes faster growth at the edges than near the face centers. This attraction draws the mineral molecules more strongly than the interior sections of the crystal, thus the edges develop more quickly. However, the basic physics of this type of growth is the same as that of dendrites but, because the anisotropy in the solid–liquid inter-facial energy is so large, the dendrite so produced exhibits a faceted morphology.<br /> <br /> Hoppering is common in many minerals, including lab-grown bismuth, galena, quartz (called skeletal or fenster crystals), gold, calcite, halite (salt), and water (ice).<br /> <br /> <table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody> <tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-oce0g7ncTsM/XQzzn64Zq8I/AAAAAAAARKQ/GtM-4GUFIHkALJT2BeWRGV_Tbc5qmwNEACLcBGAs/s1600/Galena%2B%25281%2529.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="Hopper Galena" border="0" data-original-height="557" data-original-width="736" height="302" src="https://1.bp.blogspot.com/-oce0g7ncTsM/XQzzn64Zq8I/AAAAAAAARKQ/GtM-4GUFIHkALJT2BeWRGV_Tbc5qmwNEACLcBGAs/s400/Galena%2B%25281%2529.jpg" title="" width="400" /></a></td></tr> <tr><td class="tr-caption" style="text-align: center;">Hopper Galena. Photo: Quebul Fine Minerals</td></tr> </tbody></table> <table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody> <tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-3q5lYKlcOlg/XQz0clxCDiI/AAAAAAAARKc/sKcfSvAasp49bhv4axZVymdW7egCEmSowCLcBGAs/s1600/Hopper%2Bhalite%2Bfrom%2BSieroszowice%2Bmine%2Bin%2BPoland.%2BPhoto%2BSpirifer%2BMinerals.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="Hopper halite" border="0" data-original-height="960" data-original-width="621" height="400" src="https://1.bp.blogspot.com/-3q5lYKlcOlg/XQz0clxCDiI/AAAAAAAARKc/sKcfSvAasp49bhv4axZVymdW7egCEmSowCLcBGAs/s400/Hopper%2Bhalite%2Bfrom%2BSieroszowice%2Bmine%2Bin%2BPoland.%2BPhoto%2BSpirifer%2BMinerals.jpg" title="" width="258" /></a></td></tr> <tr><td class="tr-caption" style="text-align: center;"> Hopper halite from Sieroszowice mine in Poland. <br /> Photo: Spirifer Minerals</td></tr> </tbody></table> <table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody> <tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-6ctSxbXOrfI/XQz1Mrq33jI/AAAAAAAARKk/6VAWNTbwNT4YyvgU8z1VH5RVkdBMPeBdQCLcBGAs/s1600/Bismuth.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="Bismuth" border="0" data-original-height="827" data-original-width="960" height="343" src="https://1.bp.blogspot.com/-6ctSxbXOrfI/XQz1Mrq33jI/AAAAAAAARKk/6VAWNTbwNT4YyvgU8z1VH5RVkdBMPeBdQCLcBGAs/s400/Bismuth.jpg" title="" width="400" /></a></td></tr> <tr><td class="tr-caption" style="text-align: center;"><span aria-live="polite" class="fbPhotosPhotoCaption" data-ft="{"tn":"K"}" id="fbPhotoSnowliftCaption" tabindex="0"><span class="hasCaption">Bismuth. </span></span><span aria-live="polite" class="fbPhotosPhotoCaption" data-ft="{"tn":"K"}" id="fbPhotoSnowliftCaption" tabindex="0"><span class="hasCaption">Photo: Gem_stallion </span></span></td></tr> </tbody></table> <b><span style="font-family: "georgia" , "times new roman" , serif;">See also: </span></b><br /> <span style="font-family: "georgia" , "times new roman" , serif;"><a href="https://www.geologyin.com/2014/12/what-are-crystals.html" target="_blank">What Are Crystals?</a></span><br /> <div class="pw-hidden-cp"> <span style="font-family: "georgia" , "times new roman" , serif;"><a href="https://www.geologyin.com/2014/11/crystal-structure-and-crystal-system.html" target="_blank">Crystal Structure and Crystal Systems</a></span></div> </div>

What is Hopper Crystal?

Hopper Halite crystal from Searles Lake, Trona, California. Photo: crystalminer A hopper crystal is a form of crystal, defined by its ...

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Plate Tectonics May Have Driven 'Cambrian Explosion'

<div dir="ltr" style="text-align: left;" trbidi="on"> <div class="separator" style="clear: both; text-align: center;"> <a href="https://1.bp.blogspot.com/-8FYTlxtxdiw/XQulHGyYWDI/AAAAAAAARJw/hhBydaL6-z8b98DngGQ8uvnv9UNFgDPigCLcBGAs/s1600/Burgess%2BShale%2Band%2BCambrian%2BExplosion%2B%25281%2529.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img alt="Plate Tectonics May Have Driven 'Cambrian Explosion'" border="0" data-original-height="670" data-original-width="1190" height="360" src="https://1.bp.blogspot.com/-8FYTlxtxdiw/XQulHGyYWDI/AAAAAAAARJw/hhBydaL6-z8b98DngGQ8uvnv9UNFgDPigCLcBGAs/s640/Burgess%2BShale%2Band%2BCambrian%2BExplosion%2B%25281%2529.jpg" title="" width="640" /></a></div> <br /> <h4 style="text-align: left;"> <span style="font-family: "georgia" , "times new roman" , serif;">The Cambrian Explosion –“Supernova of Biology Detonated by Plate Tectonics”</span></h4> The quest to discover what drove one of the most important evolutionary events in the history of life on Earth has taken a new, fascinating twist.<br /> <br /> A team of scientists have given a fresh insight into what may have driven the "Cambrian Explosion" -- a period of rapid expansion of different forms of animal life that occurred over 500 million years ago.<br /> <br /> While a number of theories have been put forward to explain this landmark period, the most credible is that it was fuelled by a significant rise in oxygen levels which allowed a wide variety of animals to thrive.<br /> <br /> The new study suggests that such a rise in oxygen levels was the result of extraordinary changes in global plate tectonics.<br /> <br /> During the formation of the supercontinent 'Gondwana', there was a major increase in continental arc volcanism -- chains of volcanoes often thousands of miles long formed where continental and oceanic tectonic plates collided. This in turn led to increased 'degassing' of CO₂ from ancient, subducted sedimentary rocks.<br /> <div style="margin: 0px auto; width: 100%;"> <script async="" src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script><br /> <ins class="adsbygoogle" data-ad-client="ca-pub-1021498709184325" data-ad-format="fluid" data-ad-layout="in-article" data-ad-slot="6157425841" style="display: block; text-align: center;"></ins><br /> <script> (adsbygoogle = window.adsbygoogle || []).push({}); </script><br /></div> This, the team calculated, led to an increase in atmospheric CO₂ and warming of the planet, which in turn amplified the weathering of continental rocks, which supplied the nutrient phosphorus to the ocean to drive photosynthesis and oxygen production.<br /> <br /> The study was led by Josh Williams, who began the research as an MSc student at the University of Exeter and is now studying for a PhD at the University of Edinburgh.<br /> <br /> During his MSc project he used a sophisticated biogeochemical model to make the first quantification of changes in atmospheric oxygen levels just prior to this explosion of life.<br /> <br /> Co-author and project supervisor Professor Tim Lenton, from the University of Exeter's Global Systems Institute said: "One of the great dilemmas originally recognised by Darwin is why complex life, in the form of fossil animals, appeared so abruptly in what is now known as the Cambrian explosion.<br /> <br /> "Many studies have suggested this was linked to a rise in oxygen levels -- but without a clear cause for such a rise, or any attempt to quantify it."<br /> <br /> Not only did the model predict a marked rise in oxygen levels due to changes in plate tectonic activity, but that rise in oxygen -- to about a quarter of the level in today's atmosphere -- crossed the critical levels estimated to be needed by the animals seen in the Cambrian explosion.<br /> <br /> Williams added: "What is particularly compelling about this research is that not only does the model predict a rise in oxygen to levels estimated to be necessary to support the large, mobile, predatory animal life of the Cambrian, but the model predictions also show strong agreement with existing geochemical evidence."<br /> <br /> "It is remarkable to think that our oldest animal ancestors -- and therefore all of us -- may owe our existence, in part, to an unusual episode of plate tectonics over half a billion years ago" said Professor Lenton.<br /> <br /> <br /> <br /> <u><i><span style="font-family: "trebuchet ms" , sans-serif;">The above story is based on <a href="https://www.exeter.ac.uk/news/research/title_721383_en.html" rel="nofollow" target="_blank">Materials</a> provided by <a href="http://www.exeter.ac.uk/" rel="nofollow" target="_blank">University of Exeter</a>.</span></i></u></div>

Plate Tectonics May Have Driven 'Cambrian Explosion'

The Cambrian Explosion –“Supernova of Biology Detonated by Plate Tectonics” The quest to discover what drove one of the most important...

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Fossil of a 15 Ton Sea Creature Found in Antarctica

<div dir="ltr" style="text-align: left;" trbidi="on"> <table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody> <tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-g5IQHt6SEdA/XQe_Oob6nWI/AAAAAAAARJY/n1w1y3Qk2kErx2uvvvMEGMSauc-uyXHAACLcBGAs/s1600/Fossil%2Bof%2Ba%2B15%2BTon%2BSea%2BCreature%2BFound%2Bin%2BAntarctica%2B%25281%2529.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="Fossil of a 15 Ton Sea Creature Found in Antarctica" border="0" data-original-height="800" data-original-width="1200" height="426" src="https://1.bp.blogspot.com/-g5IQHt6SEdA/XQe_Oob6nWI/AAAAAAAARJY/n1w1y3Qk2kErx2uvvvMEGMSauc-uyXHAACLcBGAs/s640/Fossil%2Bof%2Ba%2B15%2BTon%2BSea%2BCreature%2BFound%2Bin%2BAntarctica%2B%25281%2529.jpg" title="" width="640" /></a></td></tr> <tr><td class="tr-caption" style="text-align: center;">A hungry Aristonectes plesiosaur eyes a squid in this illustration.</td></tr> </tbody></table> <br /> <span style="font-family: "georgia" , "times new roman" , serif;">The prehistoric plesiosaur — a four-flippered marine reptile that lived during the dinosaur age — measured a colossal 36 feet (11 meters) long from snout to tail, about as long as a modern telephone pole. This newfound "sea monster" is now the largest known elasmosaurid (a type of plesiosaur with a long neck) on record.</span><br /> <br /> It took decades of struggling with the weather on a small, desolate island off the Antarctic Peninsula. But now, scientists have finally unearthed the heaviest known elasmosaur, an ancient aquatic reptile that swam the seas of the Cretaceous period alongside the dinosaurs. The animal would have weighed as much as 15 tons, and it is now one of the most complete ancient reptile fossils ever discovered in Antarctica.<br /> <br /> The team thinks the newly described heavyweight belongs to the genus Aristonectes, a group whose species have been seen as outliers to other elasmosaurs, since they differed so much from fossilized specimens discovered in the US. This genus, found in the Southern Hemisphere, is characterized by shorter necks and larger skulls.<br /> <br /> "For years it was a mystery ... we didn't know if they were elasmosaurs or not," says José O'Gorman, a paleontologist with the National Scientific and Technical Research Council of Argentina who is based at the Museum of La Plata near Buenos Aires. "They were some kind of weird plesiosaurs that nobody knew."<br /> <div style="margin: 0px auto; width: 100%;"> <script async="" src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script><br /> <ins class="adsbygoogle" data-ad-client="ca-pub-1021498709184325" data-ad-format="fluid" data-ad-layout="in-article" data-ad-slot="6157425841" style="display: block; text-align: center;"></ins><br /> <script> (adsbygoogle = window.adsbygoogle || []).push({}); </script><br /></div> The excavation finally finished in 2017, yielding a substantial portion of the animal's skeleton, which O'Gorman and his colleagues describe in their recent paper in Cretaceous Research.<br /> <br /> "We don't have a skull, but we have a lot of pieces of the specimen," O'Gorman says. They estimate that the as-yet-unnamed elasmosaur weighed between 11.8 tons and 14.8 tons, with a head-to-tail length of nearly 40 feet. While some previously known Aristonectes have weighed about 11 tons or so, most other elasmosaurs only come in at around five tons.<br /> <br /> He thinks the work is well done, and he's happy that the team hasn't jumped to hasty conclusions-O'Gorman even hesitates to say whether the species is definitely from the Aristonectes genus, since further evidence may put the species in a new genus entirely.<br /> <br /> The new specimen is also very interesting because it dates so close to the end of the Cretaceous-just 30,000 years before the mass extinction event that wiped out the non-avian dinosaurs about 66 million years ago. A lot of marine life would have needed to thrive there to satisfy the appetite of such a large creature, so the fact that these animals continued to exist so late in the Cretaceous adds to the evidence that the aquatic world, at least, was doing just fine right up until the sudden mass extinction.<br /> <br /> While the animal's exact diet can't be known without fossilized stomach contents or other evidence, O'Gorman says that it likely fed on crustaceans and small fish, based on the small size of its teeth. And work on the bones unearthed over the past few decades has just begun; now that they are housed in a museum, O'Gorman says there is a lot of other research that can be done on this ancient specimen.<br /> <br /> <br /> <i><u><span style="font-family: "georgia" , "times new roman" , serif;">The above story is based on <a href="https://www.sciencedirect.com/science/article/pii/S0195667118302003?dgcid=raven_sd_aip_email#!" rel="nofollow" target="_blank">materials </a>provided by Argentina's National Antarctic Directorate.</span></u></i></div>

Fossil of a 15 Ton Sea Creature Found in Antarctica

A hungry Aristonectes plesiosaur eyes a squid in this illustration. The prehistoric plesiosaur — a four-flippered marine reptile that ...

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Giant Trilobite Fossil Found on Australia

<div dir="ltr" style="text-align: left;" trbidi="on"> <table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody> <tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-YCeQn0Vb9vA/XQUTeb6lZWI/AAAAAAAARI4/3Y7MEKRgoUwHNpt1mDoGRDo6LkK47vDQQCLcBGAs/s1600/Fossils%2Bof%2Bgiant%2Bnew%2Bspecies%2Bof%2Bsea%2Bcreature%2Bfound%2Bon%2BSouth%2BAustralia%2527s%2BKangaroo%2BIsland%2B%25281%2529.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="Giant Trilobite Fossil Found on Australia" border="0" data-original-height="830" data-original-width="1200" height="442" src="https://1.bp.blogspot.com/-YCeQn0Vb9vA/XQUTeb6lZWI/AAAAAAAARI4/3Y7MEKRgoUwHNpt1mDoGRDo6LkK47vDQQCLcBGAs/s640/Fossils%2Bof%2Bgiant%2Bnew%2Bspecies%2Bof%2Bsea%2Bcreature%2Bfound%2Bon%2BSouth%2BAustralia%2527s%2BKangaroo%2BIsland%2B%25281%2529.jpg" title="" width="640" /></a></td></tr> <tr><td class="tr-caption" style="text-align: center;">A specimen of Redlichia rex from the Emu Bay Shale, Kangaroo Island, Australia. Image credit: Holmes et al, An artist’s impression of Redlichia rex on the Cambrian seafloor. Image credit: Katrina Kenny.</td></tr> </tbody></table> <div class="separator" style="clear: both; text-align: center;"> </div> <div class="separator" style="clear: both; text-align: center;"> </div> <h4 style="text-align: left;"> <span style="font-family: Georgia, "Times New Roman", serif;"> Paleontologists have unearthed fossils of a giant trilobite species that inhabited Australian waters approximately 500 million years ago (Cambrian period).</span></h4> <div style="text-align: left;"> <span style="font-family: "georgia" , "times new roman" , serif;">Fossils of a giant new species from the long-extinct group of sea creatures called trilobites have been found on Kangaroo Island, South Australia.</span></div> <div style="text-align: left;"> <br /></div> <div style="text-align: left;"> The finding is adding important insights to our knowledge of the Cambrian 'explosion', the greatest diversification event in the history of life on Earth, when almost all animal groups suddenly appeared over half-a-billion years ago.</div> <div style="text-align: left;"> <br /></div> <div style="text-align: left;"> Trilobites, which had hard, calcified, armour-like skeletons over their bodies, are related to modern crustaceans and insects. They are one of the most successful fossil animal groups, surviving for about 270 million years (521 to 252 million years ago). Because of their abundance in the fossil record, they are considered a model group for understanding this evolutionary period.</div> <div style="text-align: left;"> <br /></div> <div style="text-align: left;"> "We decided to name this new species of trilobite<i> Redlichia rex</i> (similar to <i>Tyrannosaurus rex</i>) because of its giant size, as well as its formidable legs with spines used for crushing and shredding food -- which may have been other trilobites," says James Holmes, PhD student with the University of Adelaide's School of Biological Sciences, who led the research.</div> <div style="margin: 0px auto; text-align: left; width: 100%;"> <script async="" src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script><br /> <ins class="adsbygoogle" data-ad-client="ca-pub-1021498709184325" data-ad-format="fluid" data-ad-layout="in-article" data-ad-slot="6157425841" style="display: block; text-align: center;"></ins><br /> <script> (adsbygoogle = window.adsbygoogle || []).push({}); </script><br /></div> <div style="text-align: left;"> The preservation of trilobite 'soft parts' such as the antennae and legs is extremely rare. The new species was discovered at the Emu Bay Shale on Kangaroo Island, a world-renowned deposit famous for this type of preservation. The findings have been published in the Journal of Systematic Palaeontology by a team of scientists from the University of Adelaide, South Australian Museum and the University of New England.</div> <div style="text-align: left;"> <br /></div> <div style="text-align: left;"> The new species is about 500 million years old, and is the largest Cambrian trilobite discovered in Australia. It grew to around 30 cm in length, which is almost twice the size of other Australian trilobites of similar age.</div> <div style="text-align: left;"> <br /></div> <div style="text-align: left;"> "Interestingly, trilobite specimens from the Emu Bay Shale -- including <i>Redlichia rex</i> -- exhibit injuries that were caused by shell-crushing predators," says senior study author Associate Professor Diego García-Bellido, from the University of Adelaide and the South Australian Museum.</div> <div style="text-align: left;"> <br /></div> <div style="text-align: left;"> "There are also large specimens of fossilised poo (or coprolites) containing trilobite fragments in this fossil deposit. The large size of injured <i>Redlichia rex</i> specimens and the associated coprolites suggests that either much bigger predators were targeting <i>Redlichia rex</i>, such as Anomalocaris -- an even larger shrimp-like creature -- or that the new species had cannibalistic tendencies."</div> <div style="text-align: left;"> <br /></div> <div style="text-align: left;"> One of the major drivers of the Cambrian explosion was likely an evolutionary "arms race" between predators and prey, with each developing more effective measures of defence (such as the evolution of shells) and attack.</div> <div style="text-align: left;"> <br /></div> <div style="text-align: left;"> "The overall size and crushing legs of <i>Redlichia rex</i> are a likely consequence of the arms race that occurred at this time" says James Holmes. "This giant trilobite was likely the terror of smaller creatures on the Cambrian seafloor."</div> <div style="text-align: left;"> <br /></div> <div style="text-align: left;"> Specimens of Redlichia rex and other Emu Bay Shale fossils are currently on display in the South Australian Museum.</div> <div style="text-align: left;"> <br /></div> <div style="text-align: left;"> <br /></div> <div style="text-align: left;"> <br /></div> <div style="text-align: left;"> <u><i><span style="font-family: "trebuchet ms" , sans-serif;">The above story is based on <a href="https://www.adelaide.edu.au/news/news107262.html" rel="nofollow" target="_blank">Materials</a> provided by <a href="https://www.adelaide.edu.au/" rel="nofollow" target="_blank">University of Adelaide</a>.</span></i></u></div> </div>

Giant Trilobite Fossil Found on Australia

A specimen of Redlichia rex from the Emu Bay Shale, Kangaroo Island, Australia. Image credit: Holmes et al, An artist’s impression of Red...

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What is Fire Agate, And Where to Find it?

<div dir="ltr" style="text-align: left;" trbidi="on"><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-9Leq0Am9gzo/YXBF28DhrxI/AAAAAAAATXw/G0QiNhYgOpkCZQCq-tNbtNg-e8RvUH3vgCLcBGAsYHQ/s1232/IoD_Shearer_17490_1%2B%25281%2529.jpg" style="margin-left: auto; margin-right: auto;"><img alt="What is Fire Agate, And Where to Find it?" border="0" data-original-height="892" data-original-width="1232" height="290" src="https://1.bp.blogspot.com/-9Leq0Am9gzo/YXBF28DhrxI/AAAAAAAATXw/G0QiNhYgOpkCZQCq-tNbtNg-e8RvUH3vgCLcBGAsYHQ/w400-h290/IoD_Shearer_17490_1%2B%25281%2529.jpg" title="Polished Mexican fire agate" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">Fire agate by Photographer Thomas Shearer</td></tr></tbody></table>  <br /><br /> <br /> <span style="font-family: "georgia" , "times new roman" , serif;">Agate is a semi-precious gemstone formed by relatively recent volcanic activity. It is outwardly similar in appearance to quartz, but also shows interesting swirls, bubbles and patterns.</span><br /> <br /> Fire agate, a variety of chalcedony, is a semi-precious natural gemstone discovered so far only in certain areas of central and northern Mexico and the southwestern United States (New Mexico, Arizona and California). <br /> <table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody> <tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-N26_INSvX8c/Xkk9vMiTyjI/AAAAAAAAR7c/sGgwDfZwXUcfMmOAZRgoAlsqNVpfVV_VACLcBGAsYHQ/s1600/What%2Bis%2BFire%2BAgate%2B%25281%2529.jpg" style="margin-left: auto; margin-right: auto;"><img alt="What is Fire Agate, And Where to Find it?" border="0" data-original-height="1052" data-original-width="1600" height="263" src="https://1.bp.blogspot.com/-N26_INSvX8c/Xkk9vMiTyjI/AAAAAAAAR7c/sGgwDfZwXUcfMmOAZRgoAlsqNVpfVV_VACLcBGAsYHQ/w400-h263/What%2Bis%2BFire%2BAgate%2B%25281%2529.jpg" width="400" /></a></td></tr> <tr><td class="tr-caption" style="text-align: center;">Fire agate by Photographer Thomas Shearer</td></tr> </tbody></table><br /> Fire agates have beautiful iridescent rainbow colors, similar to opal, with a measurement of hardness on the Mohs scale of between 5 and 7 which reduces the occurrence of scratching when polished gemstones are set in jewelry.<br /> <div style="margin: 0px auto; width: 100%;"> <script async="" src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script><br /> <ins class="adsbygoogle" data-ad-client="ca-pub-1021498709184325" data-ad-format="fluid" data-ad-layout="in-article" data-ad-slot="6157425841" style="display: block; text-align: center;"></ins><br /> <script> (adsbygoogle = window.adsbygoogle || []).push({}); </script><br /></div> The vibrant iridescent rainbow colors found within fire agates, created by the Schiller effect as found in mother-of-pearl, is caused by the alternating silica and iron oxide layers which diffract and allow light to pass and form an interference of colors within the microstructure layering of the stone causing the fire effect for which it is named.<br /> <br /> <table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody> <tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-Ow8s2Mlu69E/XQOw2bLwNFI/AAAAAAAARIg/t65k3j1NoxI2uMdtkqtn54iGijnIExzEwCLcBGAs/s1600/Fire%2Bagate.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1033" data-original-width="1200" height="343" src="https://1.bp.blogspot.com/-Ow8s2Mlu69E/XQOw2bLwNFI/AAAAAAAARIg/t65k3j1NoxI2uMdtkqtn54iGijnIExzEwCLcBGAs/s400/Fire%2Bagate.jpg" width="400" /></a></td></tr> <tr><td class="tr-caption" style="text-align: center;">Photo: Isaac Jones</td></tr> </tbody></table> <h4 style="text-align: left;"> <span style="font-family: "georgia" , "times new roman" , serif;">How Fire Agate and Chalcedony Form</span></h4> The fire agate and chalcedony of the Southern New Mexico–Arizona border area is formed when low pressure and low temperature epithermal hydrothermal waters (50°-200°C / 122°-392°F) carrying colloidal SiO₂ and iron oxides are injected into cavities in volcanic rocks such as gas bubbles in flow rocks, irregular-shaped vug fillings, or along fault or bedding plane fractures.<br /> <div style="margin: 0px auto; width: 100%;"> <script async="" src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script><br /> <ins class="adsbygoogle" data-ad-client="ca-pub-1021498709184325" data-ad-format="fluid" data-ad-layout="in-article" data-ad-slot="6157425841" style="display: block; text-align: center;"></ins><br /> <script> (adsbygoogle = window.adsbygoogle || []).push({}); </script><br /></div> Approximately 24-36 million years ago these areas were subjected to massive volcanic activity during the Tertiary Period. The fire agates were formed during this period of volcanism when hot water, saturated with silica and iron oxide, repeatedly filled cracks and bubbles in the surrounding rock.<br /> <h4> <span style="color: blue;"><span style="font-family: "georgia" , "times new roman" , serif;">Fire Agate Gemstone Mineral Locations</span></span></h4> <b><span style="font-family: "georgia" , "times new roman" , serif;">Deer Creek, Arizona</span></b><br /> Deer Creek Fire agate is well known for it's high quality fire agate gemstones and excellent lapidary rough. The fire agate from Deer Creek Arizona ranks high on the list of desired collected gemstones, mineral specimens, and lapidary gemstone cutting material. Located in the eastern foothills of the Galiuro Mountains southwest of Safford, Arizona, this area has several active fire agate mines. Some of the early pioneers in fire agate mining at Deer Creek were Larry Gray, Howard Imboden, Guy Paul and Cliff Willis.<br /> <br /> <b><span style="font-family: "georgia" , "times new roman" , serif;">Cuesta Fire Agate Mine - Arizona</span></b><br /> <a href="http://cuestafireagatemine.ilandwyte.com/" rel="nofollow" target="_blank">Cuesta Fire Agate</a> mine is a Desert Dig. when you come out to the Mine, you go to the claims and you can dig to your hearts content. without restrictions to what or where you can Dig. The Mine is open 12 months of the year.  fee: $30.00 - $50.00 a day, Tool Rentals, $5.00 a day.<br /> Address:  old Route 66 4 miles north of Oatman, AZ.<br /> <br /> <b><span style="font-family: "georgia" , "times new roman" , serif;">Slaughter Mountain - Arizona </span></b><br /> Known for it's high quality fire agate gemstones and with it's rough often having multiple layers of fire banding, <a href="http://www.slaughtermountainfireagate.com/?fbclid=IwAR1h4VQFkhthjNQ6SmblrxSntpGXDxpAN0jAS7gg0Hj7_Dbi5vBwIjoC0Uk" rel="nofollow" target="_blank">Slaughter Mountain Fire</a> Agate is well suited for gemstone carving purposes. The mine at Slaughter Mountain is known for producing high quality fire agate gemstones, with intense color variations from bright reds and oranges to intense greens, purples and blues.<br /> <table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody> <tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-Ea3DXRcCNyc/XQO5ztcGEhI/AAAAAAAARIs/19N2Uhc6sRcNQdIUMjf2JoJDqZb3oaAqgCLcBGAs/s1600/fire%2Bagate%2B%25282%2529.jpg" style="margin-left: auto; margin-right: auto;"><img alt="What is Fire Agate?" border="0" data-original-height="1177" data-original-width="1200" height="391" src="https://1.bp.blogspot.com/-Ea3DXRcCNyc/XQO5ztcGEhI/AAAAAAAARIs/19N2Uhc6sRcNQdIUMjf2JoJDqZb3oaAqgCLcBGAs/s320/fire%2Bagate%2B%25282%2529.jpg" title="" width="400" /></a></td></tr> <tr><td class="tr-caption" style="text-align: center;">Photo Credit: Glenn Dizon </td></tr> </tbody></table> <b><span style="font-family: "georgia" , "times new roman" , serif;">See also:</span></b><br /> <a href="https://www.geologyin.com/2019/04/what-is-grape-agate.html" target="_blank">What Is Grape Agate?</a><br /> <a href="https://www.geologyin.com/2018/04/tourmaline-species-and-color-varieties.html" target="_blank">Tourmaline: Species and Color Varieties</a><br /> <a href="https://www.geologyin.com/2018/03/types-of-iridescent-gemstones-minerals.html" target="_blank">Types of Iridescent Gemstones & Minerals </a></div><br />

What is Fire Agate, And Where to Find it?

Fire agate by Photographer Thomas Shearer   Agate is a semi-precious gemstone formed by relatively recent volcanic activity. It is outward...

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1.2 Billion-Year-Old Meteorite Crater Discovered in Scotland

<div dir="ltr" style="text-align: left;" trbidi="on"> <div class="separator" style="clear: both; text-align: center;"> </div> <table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody> <tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-Af6g-f_0YHk/XP_ljGa3jNI/AAAAAAAARII/PjsEWJb1-JEAoqJA_maImHdredio8OUGwCLcBGAs/s1600/scotland-meteor-1%2B%25281%2529.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="1.2 Billion-Year-Old Meteorite Crater Discovered in Scotland" border="0" data-original-height="584" data-original-width="1220" height="306" src="https://1.bp.blogspot.com/-Af6g-f_0YHk/XP_ljGa3jNI/AAAAAAAARII/PjsEWJb1-JEAoqJA_maImHdredio8OUGwCLcBGAs/s640/scotland-meteor-1%2B%25281%2529.jpg" title="" width="640" /></a></td></tr> <tr><td class="tr-caption" style="text-align: center;">Reddish-colored rocks of the Stac Fada deposit. Image: University of Oxford</td></tr> </tbody></table> <div class="separator" style="clear: both; text-align: center;"> </div> <div class="separator" style="clear: both; text-align: center;"> </div> <br /> The biggest ever recorded meteorite collision location has been discovered in the U.K. Scientists find 9 MILE wide crater in Scotland caused by the 'biggest meteorite collision in Britain's history' 1.2 billion years ago<br /> <br /> Evidence for the ancient, 1.2 billion years old, meteorite strike, was first discovered in 2008 near Ullapool, NW Scotland by scientists from Oxford and Aberdeen Universities. The thickness and extent of the debris deposit they found suggested the impact crater -- made by a meteorite estimated at 1km wide -- was close to the coast, but its precise location remained a mystery.<br /> <br /> In a paper published today in Journal of the Geological Society, a team led by Dr Ken Amor from the Department of Earth Sciences at Oxford University, show how they have identified the crater location 15-20km west of a remote part of the Scottish coastline. It is buried beneath both water and younger rocks in the Minch Basin.<br /> <br /> Dr Ken Amor said: 'The material excavated during a giant meteorite impact is rarely preserved on Earth, because it is rapidly eroded, so this is a really exciting discovery. It was purely by chance this one landed in an ancient rift valley where fresh sediment quickly covered the debris to preserve it.<br /> <br /> 'The next step will be a detailed geophysical survey in our target area of the Minch Basin.'<br /> <div style="margin: 0px auto; width: 100%;"> <script async="" src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script><br /> <ins class="adsbygoogle" data-ad-client="ca-pub-1021498709184325" data-ad-format="fluid" data-ad-layout="in-article" data-ad-slot="6157425841" style="display: block; text-align: center;"></ins><br /> <script> (adsbygoogle = window.adsbygoogle || []).push({}); </script><br /></div> Using a combination of field observations, the distribution of broken rock fragments known as basement clasts and the alignment of magnetic particles, the team was able to gauge the direction the meteorite material took at several locations, and plotted the likely source of the crater.<br /> <br /> Dr Ken Amor said: 'It would have been quite a spectacle when this large meteorite struck a barren landscape, spreading dust and rock debris over a wide area.'<br /> <br /> 1.2 billion years ago most of life on Earth was still in the oceans and there were no plants on the land. At that time Scotland would have been quite close to the equator and in a semi-arid environment. The landscape would have looked a bit like Mars when it had water at the surface.<br /> <br /> Earth and other planets may have suffered a higher rate of meteorite impacts in the distant past, as they collided with debris left over from the formation of the early solar system.<br /> <br /> However, there is a possibility that a similar event will happen in the future given the number of asteroid and comet fragments floating around in the solar system. Much smaller impacts, where the meteorite is only a few meters across are thought to be relatively common perhaps occurring about once every 25 years on average.<br /> <br /> It is thought that collisions with an object about 1 km (as in this instance) across occur between once every 100,000 years to once every one million years -- but estimates vary.<br /> <br /> One of the reasons for this is that our terrestrial record of large impacts is poorly known because craters are obliterated by erosion, burial and plate tectonics.<br /> <br /> <br /> <u><i><span style="font-family: "trebuchet ms" , sans-serif;">The above story is based on <a href="http://www.ox.ac.uk/news/2019-06-10-site-biggest-ever-meteorite-collision-uk-discovered" rel="nofollow" target="_blank">Materials</a> provided by <a href="http://www.ox.ac.uk/" rel="nofollow" target="_blank">University of Oxford</a>.</span></i></u></div>

1.2 Billion-Year-Old Meteorite Crater Discovered in Scotland

Reddish-colored rocks of the Stac Fada deposit. Image: University of Oxford The biggest ever recorded meteorite collision locati...

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What Jumpstarted Earth's Plate Tectonics?

<div dir="ltr" style="text-align: left;" trbidi="on"> <table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody> <tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-KoHXiZU1EHA/XPvqxbDEE5I/AAAAAAAARFI/IT1vdRIsv5EzlkXNDePTv8pdWCS4daGQACLcBGAs/s1600/What%2BJumpstarted%2BEarth%2527s%2BPlate%2BTectonics%2B%25281%2529.jpg" style="margin-left: auto; margin-right: auto;"><img alt="What Jumpstarted Earth's Plate Tectonics?" border="0" data-original-height="687" data-original-width="1226" height="358" src="https://1.bp.blogspot.com/-KoHXiZU1EHA/XPvqxbDEE5I/AAAAAAAARFI/IT1vdRIsv5EzlkXNDePTv8pdWCS4daGQACLcBGAs/w640-h358/What%2BJumpstarted%2BEarth%2527s%2BPlate%2BTectonics%2B%25281%2529.jpg" title="What Jumpstarted Earth's Plate Tectonics?" width="640" /></a></td></tr> <tr><td class="tr-caption" style="text-align: center;">What Jumpstarted Earth's Plate Tectonics? World Tectonic Plates and Their Movement -</td></tr> </tbody></table> <br /> <br /> Earth's outer layer is composed of giant plates that grind together, sliding past or dipping beneath one another, giving rise to earthquakes and volcanoes. These plates also separate at undersea mountain ridges, where molten rock spreads from the centers of ocean basins.<br /> <br /> But this was not always the case. Early in Earth's history, the planet was covered by a single shell dotted with volcanoes -- much like the surface of Venus today. As Earth cooled, this shell began to fold and crack, eventually creating Earth's system of plate tectonics.<br /> <br /> According to new research, the transition to <a href="https://www.geologyin.com/2014/09/how-plate-tectonics-works.html" target="_blank">plate tectonics</a> started with the help of lubricating sediments, scraped by glaciers from the slopes of Earth's first continents. As these sediments collected along the world's young coastlines, they helped to accelerate the motion of newly formed subduction faults, where a thinner oceanic plate dips beneath a thicker continental plate.<br /> <br /> The new study, published in the journal<i> Nature</i>, is the first to suggest a role for sediments in the emergence and evolution of global plate tectonics. Michael Brown, a professor of geology at the University of Maryland, co-authored the research paper with Stephan Sobolev, a professor of geodynamics at the GFZ German Research Centre for Geosciences in Potsdam.<br /> <br /> The findings suggest that sediment lubrication controls the rate at which Earth's crust grinds and churns. Sobolev and Brown found that two major periods of worldwide glaciation, which resulted in massive deposits of glacier-scrubbed sediment, each likely caused a subsequent boost in the global rate of plate tectonics.<br /> <br /> The most recent such episode followed the "snowball Earth" that ended sometime around 635 million years ago, resulting in Earth's modern plate tectonic system.<br /> <div style="margin: 0px auto; width: 100%;"> <script async="" src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script><br /> <ins class="adsbygoogle" data-ad-client="ca-pub-1021498709184325" data-ad-format="fluid" data-ad-layout="in-article" data-ad-slot="6157425841" style="display: block; text-align: center;"></ins><br /> <script> (adsbygoogle = window.adsbygoogle || []).push({}); </script><br /></div> "Earth hasn't always had plate tectonics and it hasn't always progressed at the same pace," Brown said. "It's gone through at least two periods of acceleration. There's evidence to suggest that tectonics also slowed to a relative crawl for nearly a billion years. In each case, we found a connection with the relative abundance -- or scarcity -- of glacial sediments."<br /> <br /> Just as a machine needs grease to keep its parts moving freely, plate tectonics operates more efficiently with lubrication. While it may be hard to confuse the gritty consistency of clay, silt, sand and gravel with a slippery grease, the effect is largely the same at the continental scale, in the ocean trenches where tectonic plates meet.<br /> <br /> "The same dynamic exists when drilling Earth's crust. You have to use mud -- a very fine clay mixed with water or oil -- because water or oil alone won't work as well," Brown said. "The mud particles help reduce friction on the drill bit. Our results suggest that tectonic plates also need this type of lubrication to keep moving."<br /> <br /> Previous research on the western coast of South America was the first to identify a relationship between sediment lubrication and friction along a subduction fault. Off the coast of northern Chile, a relative lack of sediment in the fault trench creates high friction as the oceanic Nazca plate dips beneath the continental South America plate. This friction helped to push the highest peaks of the central Andes Mountains skyward as the continental plate squashed and deformed.<br /> <br /> In contrast, further south there is a higher sediment load in the trench, resulting in less friction. This caused less deformation of the continental plate and, consequently, created smaller mountain peaks. But these findings were limited to one geographic area.<br /> <br /> For their study, Sobolev and Brown used a geodynamic model of plate tectonics to simulate the effect of sediment lubrication on the rate of subduction. To verify their hypothesis, they checked for correlations between known periods of widespread glaciation and previously published data that indicate the presence of continental sediment in the oceans and trenches. For this step, Sobolev and Brown relied on two primary lines of evidence: the chemical signature of the influence of continental sediments on the chemistry of the oceans and indicators of sediment contamination in subduction-related volcanoes, much like those that make up today's "ring of fire" around the Pacific Ocean.<br /> <br /> According to Sobolev and Brown's analysis, plate tectonics likely emerged on Earth between 3 and 2.5 billion years ago, around the time when Earth's first continents began to form. This time frame also coincides with the planet's first continental glaciation.<br /> <br /> A major boost in plate tectonics then occurred between 2.2 to 1.8 billion years ago, following another global ice age that scrubbed massive amounts of sediments into the fault trenches at the edges of the continents.<br /> <br /> The next billion years, from 1.75 billion to 750 million years ago, saw a global reduction in the rate of plate tectonics. This stage of Earth's history was so sedate, comparatively speaking, that it earned the nickname "the boring billion" among geologists.<br /> <br /> Later, following the global "snowball Earth" glaciation that ended roughly 635 million years ago, the largest surface erosion event in Earth's history may have scrubbed more than a vertical mile of thickness from the surface of the continents. According to Sobolev and Brown, when these sediments reached the oceans, they kick-started the modern phase of active plate tectonics.<br /> <br /> <br /> <br /> <u><i><span face=""trebuchet ms" , sans-serif">The above story is based on <a href="http://dx.doi.org/10.1038/s41586-019-1258-4" rel="nofollow" target="_blank">Materials </a>provided by <a href="https://www.umd.edu/" rel="nofollow" target="_blank">University of Maryland</a>.</span></i></u></div>

What Jumpstarted Earth's Plate Tectonics?

What Jumpstarted Earth's Plate Tectonics? World Tectonic Plates and Their Movement - Earth's outer layer is composed of giant...

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Study Confirms Banded Iron Formations Originated From Oxidized Iron

<div dir="ltr" style="text-align: left;" trbidi="on"> <table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody> <tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-x51AGUW--IY/XPqKo-XUyEI/AAAAAAAAREw/cRSGErTkSjwdtNgCBS6jZlIK5THkg8H8wCLcBGAs/s1600/Study%2Bconfirms%2Bbanded%2Biron%2Bformations%2Boriginated%2Bfrom%2Boxidized%2Biron%2B%25281%2529.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="866" data-original-width="1204" height="460" src="https://1.bp.blogspot.com/-x51AGUW--IY/XPqKo-XUyEI/AAAAAAAAREw/cRSGErTkSjwdtNgCBS6jZlIK5THkg8H8wCLcBGAs/s640/Study%2Bconfirms%2Bbanded%2Biron%2Bformations%2Boriginated%2Bfrom%2Boxidized%2Biron%2B%25281%2529.jpg" width="640" /></a></td></tr> <tr><td class="tr-caption" style="text-align: center;">2.1 billion year old rock showing banded iron formation. Photo: André Karwath</td></tr> </tbody></table> <br /> <span style="font-family: "georgia" , "times new roman" , serif;">A new study by University of Alberta scientists shows that <a href="https://www.geologyin.com/2014/06/banded-iron-formations.html" target="_blank">banded iron formations </a>originated from oxidized iron, confirming the relevance and accuracy of existing models -- a finding of great importance to the geological community.</span><br /> <br /> Banded iron formations are a distinct type of sedimentary rock with layers of iron deposited as horizontal bands. The majority of these formations formed over the last 2.5 billion years and are a major source of iron today. "We've been using banded iron formations with great success to track the evolution of seawater chemistry and evolution of the biosphere," explained Kurt Konhauser, professor in the Department of Earth and Atmospheric Sciences and co-author on the paper. "But these experiments are based on the assumption that we understand the primary minerals that compose these rocks."<br /> <br /> In the last decade, a new model was proposed, suggesting that the formations began as ferrous iron that was later oxidized by oxygen in the environment -- a model that, if correct, would require a major paradigm shift in this area of study.<br /> <div style="margin: 0px auto; width: 100%;"> <script async="" src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script><br /> <ins class="adsbygoogle" data-ad-client="ca-pub-1021498709184325" data-ad-format="fluid" data-ad-layout="in-article" data-ad-slot="6157425841" style="display: block; text-align: center;"></ins><br /> <script> (adsbygoogle = window.adsbygoogle || []).push({}); </script><br /></div> To examine this possibility, a group of researchers led by Konhauser's PhD student Leslie Robbins tested the theory using a hydrogeological model, designed to determine how long it would take oxygen to oxidize such a formation. The research team included Professor Ben Roston, Assistant Professor Daniel Alessi, and Professor Larry Heaman.<br /> <br /> "Essentially, we found that this would be possible in only one per cent of cases in the suggested time frame of 250 million years," said Konhauser. "Moreover, we had to create unrealistic conditions in order to make the new proposed model work -- for instance, an extremely steep slope, or rock that was actually sand, or a great deal of oxygen."<br /> <br /> These results confirmed that the newly proposed model is inaccurate, indicating that existing models and our current understanding remains the most effective method of studying banded iron formations.<br /> <br /> "This is a powerful result that stems from the simple question about whether recently proposed models for <a href="https://www.geologyin.com/2014/06/banded-iron-formations.html" target="_blank">banded iron formations</a> are plausible when extrapolated to the size of a depositional basin," said Robbins, now a postdoctoral fellow at Yale University in New Haven, United States. "This result has fundamental implications for the formation of these deposits, and this work benefited greatly from strong collaborations both within Earth and Atmospheric Sciences and with our external collaborators."<br /> <br /> <br /> <br /> <i><u><span style="font-family: "trebuchet ms" , sans-serif;">The above story is based on <a href="https://www.ualberta.ca/science/science-news/2019/june/banded-iron-formations-origin" rel="nofollow" target="_blank">Materials</a> provided by <a href="http://www.ualberta.ca/" rel="nofollow" target="_blank">University of Alberta</a>. Original written by Katie Willis.</span></u></i></div>

Study Confirms Banded Iron Formations Originated From Oxidized Iron

2.1 billion year old rock showing banded iron formation. Photo: André Karwath A new study by University of Alberta scientists shows th...

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Iridescent Bones of a Lost Dinosaur Herd Discovered in an Opal Mine

<div dir="ltr" style="text-align: left;" trbidi="on"> <table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody> <tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-_cM47ATnbcY/XPqfv8gjHxI/AAAAAAAARE8/aIqEvbLVZ74FhmxzL3eG3PL27JVhJj02gCLcBGAs/s1600/Iridescent%2BBones%2Bof%2Ba%2BLost%2BDinosaur%2BHerd%2BDiscovered%2Bin%2Ban%2BOpal%2BMine.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="Iridescent Bones of a Lost Dinosaur Herd Discovered in an Opal Mine" border="0" data-original-height="730" data-original-width="1300" height="358" src="https://1.bp.blogspot.com/-_cM47ATnbcY/XPqfv8gjHxI/AAAAAAAARE8/aIqEvbLVZ74FhmxzL3eG3PL27JVhJj02gCLcBGAs/s640/Iridescent%2BBones%2Bof%2Ba%2BLost%2BDinosaur%2BHerd%2BDiscovered%2Bin%2Ban%2BOpal%2BMine.jpg" title="" width="640" /></a></td></tr> <tr><td class="tr-caption" style="text-align: center;">A fossil vertebrae of the newly discovered dinosaur species Fostoria dhimbangunmal discovered in opal.<br /> Credit: Robert A. Smith/Australian Opal Centre</td></tr> </tbody></table> <h4> <span style="font-family: Georgia, "Times New Roman", serif;"></span><span style="font-family: Georgia, "Times New Roman", serif;">Dinosaur bones are precious, especially when they come filled with Gemstones.</span><span style="font-family: Georgia, "Times New Roman", serif;"></span></h4> Back in the 1980s, a miner unearthed a slew of fossils preserved in opals in an opal mine near Lightning Ridge in Australia. A recent analysis of those opalized fossils revealed that they held the remains of a herd of dinosaurs — including the world's most complete opalized dinosaur. <br /> <br /> Scientists have revealed that fossils from an underground opal mine near Lightning Ridge, outback NSW, include remains from a herd of dinosaurs, among them a new dinosaur species and the world's most complete opalised dinosaur.<br /> <br /> <a href="https://www.geologyin.com/2017/03/how-do-opalised-fossils-form.html" target="_blank">See: How Do Opalised Fossils Form?</a><br /> <br /> Dr Phil Bell, lead researcher from the University of New England in Armidale, said he was stunned by the sheer number of bones found. “We initially assumed it was a single skeleton, but when I started looking at some of the bones, I realised that we had four scapulae (shoulder blades) all from different sized animals.” It is the first dinosaur ‘herd’ to be discovered in Australia.<br /> <br /> The new dinosaur has been named Fostoria dhimbangunmal in honour of opal miner Robert Foster, who discovered the fossils in the 1980s. The species name, dhimbangunmal (pronounced bim-baan goon-mal), means ‘sheep yard’ in the local Yuwaalaraay and Yuwaalayaay languages, in recognition of the Sheepyard locality where the bones were found.<br /> <div style="margin: 0px auto; width: 100%;"> <script async="" src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script><br /> <ins class="adsbygoogle" data-ad-client="ca-pub-1021498709184325" data-ad-format="fluid" data-ad-layout="in-article" data-ad-slot="6157425841" style="display: block; text-align: center;"></ins><br /> <script> (adsbygoogle = window.adsbygoogle || []).push({}); </script><br /></div> “There are about 60 opalised bones from one adult dinosaur, including part of the braincase, and bones from at least another three animals” said Dr Phil Bell.<br /> <br /> In total, parts of four Fostoria skeletons were unearthed, ranging from small juveniles to larger animals that might have been five metres in length, prompting speculation they were part of a small herd or family.<br /> <br /> The bones, which are mostly grey potch opal, were found in the 1980s by opal miner Robert Foster at the Sheepyard opal field, near Lightning Ridge. Scientists from the Australian Museum in Sydney helped excavate the fossils, but the bones remained unstudied until donated to the Australian Opal Centre by Robert's children Gregory and Joanne Foster in 2015, under the Federal Government’s Cultural Gift Program.<br /> <br /> Jenni Brammall, palaeontologist and special projects officer of the Australian Opal Centre, says, "Fostoria has given us the most complete opalised dinosaur skeleton in the world. Partial skeletons of extinct swimming reptiles have been found at other Australian opal fields, but for opalised dinosaurs we generally have only a single bone or tooth or in rare instances, a few bones. To recover dozens of bones from the one skeleton is a first."<br /> <br /> Fostoria was a two-legged plant-eating iguanodontian dinosaur closely related to the famous Muttaburrasaurus from central Queensland, which was discovered in 1980.<br /> <br /> The discovery comes on the back of the new small plant-eating dinosaur also from Lightning Ridge, Weewarrasaurus pobeni, which was named by Dr Bell and colleagues late last year.<br /> <br /> “The rate of discovery is astounding. On average, there’s at least one new dinosaur discovered around the world every week,” Dr Bell said. "With more palaeontologists and scientists looking further afield than ever before, it’s an exciting time for dinosaur lovers everywhere, especially in Australia."<br /> <br /> <br /> <u><i><span style="font-family: "trebuchet ms" , sans-serif;">The above story is based on <a href="https://www.une.edu.au/connect/news/2019/05/herd-of-dinosaurs-found-underground-at-lightning-ridge" rel="nofollow" target="_blank">materials </a>provided by <a href="https://www.une.edu.au/" rel="nofollow" target="_blank">The University of New England.</a></span></i></u></div>

Iridescent Bones of a Lost Dinosaur Herd Discovered in an Opal Mine

A fossil vertebrae of the newly discovered dinosaur species Fostoria dhimbangunmal discovered in opal. Credit: Robert A. Smith/Australia...

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Magnetism Discovered in the Earth's Mantle

<div dir="ltr" style="text-align: left;" trbidi="on"> <table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody> <tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-EiO4MuWFY04/XPktuArLIkI/AAAAAAAAREk/Fw5O5wcmwXsfF_MaN_d6z_ObXBcjOOrYgCLcBGAs/s1600/Magnetism%2Bdiscovered%2Bin%2Bthe%2BEarth%2527s%2Bmantle%2B%25281%2529.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="Magnetism Discovered in the Earth's Mantle" border="0" data-original-height="1102" data-original-width="1219" height="578" src="https://1.bp.blogspot.com/-EiO4MuWFY04/XPktuArLIkI/AAAAAAAAREk/Fw5O5wcmwXsfF_MaN_d6z_ObXBcjOOrYgCLcBGAs/s640/Magnetism%2Bdiscovered%2Bin%2Bthe%2BEarth%2527s%2Bmantle%2B%25281%2529.jpg" title="" width="640" /></a></td></tr> <tr><td class="tr-caption" style="text-align: center;">The interior of the Earth and the experiment graphically illustrated. The blue dotted lines show the magnetic field surrounding the Earth. The researchers pressed and heated samples of the iron oxide hematite found in the Earth's mantle between two diamonds (right) to simulate the extreme conditions in the Earth's mantle. They observed that the iron oxide is magnetic under these conditions. Credit: Timofey Fedotenko</td></tr> </tbody></table> <br /> <div style="text-align: left;"> The huge magnetic field which surrounds the Earth, protecting it from radiation and charged particles from space—and which many animals even use for orientation purposes—is changing constantly, which is why geoscientists keep it constantly under surveillance. </div> <div style="text-align: left;"> <br /></div> <div style="text-align: left;"> The old well-known sources of the Earth's magnetic field are the Earth's core—down to 6,000 kilometres deep down inside the Earth—and the Earth's crust: in other words, the ground we stand on. The Earth's mantle, on the other hand, stretching from 35 to 2,900 kilometres below the Earth's surface, has so far largely been regarded as "magnetically dead." An international team of researchers from Germany, France, Denmark and the U.S. has now demonstrated that a form of iron oxide, hematite, can retain its magnetic properties even deep down in the Earth's mantle. This occurs in relatively cold tectonic plates, called slabs, which are found especially beneath the western Pacific Ocean.<br /> <br /> "This new knowledge about the Earth's mantle and the strongly magnetic region in the western Pacific could throw new light on any observations of the Earth's magnetic field," says mineral physicist and first author Dr. Ilya Kupenko from the University of Münster (Germany). The new findings could, for example, be relevant for any future observations of the magnetic anomalies on the Earth and on other planets such as Mars. This is because Mars has no longer a dynamo and thus no source enabling a strong magnetic field originating from the core to be built up such as that on Earth. It might, therefore, now be worth taking a more detailed look on its mantle. The study has been published in Nature.</div> <h4 style="text-align: left;"> <span style="font-family: "georgia" , "times new roman" , serif;">Background and methods used</span></h4> <div style="text-align: left;"> Deep in the metallic core of the Earth, it is liquid iron alloy that triggers electrical flows. In the outermost crust of the Earth, rocks cause magnetic signal. In the deeper regions of the Earth's interior, however, it was believed that the rocks lose their magnetic properties due to the very high temperatures and pressures.<br /> <div style="margin: 0px auto; width: 100%;"> <script async="" src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script><br /> <ins class="adsbygoogle" data-ad-client="ca-pub-1021498709184325" data-ad-format="fluid" data-ad-layout="in-article" data-ad-slot="6157425841" style="display: block; text-align: center;"></ins><br /> <script> (adsbygoogle = window.adsbygoogle || []).push({}); </script><br /></div> The researchers now took a closer look at the main potential sources for magnetism in the Earth's mantle: iron oxides, which have a high critical temperature—i.e. the temperature above which material is no longer magnetic. In the Earth's mantle, iron oxides occur in slabs that are buried from the Earth's crust further into the mantle, as a result of tectonic shifts, a process called subduction. They can reach a depth within the Earth's interior of between 410 and 660 kilometres—the so-called transition zone between the upper and the lower mantle of the Earth. Previously, however, no one had succeeded in measuring the magnetic properties of the iron oxides at the extreme conditions of pressure and temperature found in this region.<br /> <br /> Now the scientists combined two methods. Using a so-called diamond anvil cell, they squeezed micrometric-sized samples of iron oxide hematite between two diamonds, and heated them with lasers to reach pressures of up to 90 gigapascal and temperatures of over 1,000 °C (1,300 K). The researchers combined this method with so-called Mössbauer spectroscopy to probe the magnetic state of the samples by means of synchrotron radiation. This part of the study was carried out at the ESRF synchrotron facility in Grenoble, France, and this made it possible to observe the changes of the magnetic order in iron oxide.<br /> <br /> The surprising result was that the hematite remained magnetic up to a temperature of around 925 °C (1,200 K) – the temperature prevailing in the subducted slabs beneath the western part of Pacific Ocean at the Earth's transition zone depth. "As a result, we are able to demonstrate that the Earth's mantle is not nearly as magnetically 'dead' as has so far been assumed," says Prof. Carmen Sanchez-Valle from the Institute of Mineralogy at Münster University. "These findings might justify other conclusions relating to the Earth's entire magnetic field," she adds.</div> <h4 style="text-align: left;"> <span style="font-family: "georgia" , "times new roman" , serif;">Relevance for investigations of the Earth's magnetic field and the movement of the poles</span></h4> <div style="text-align: left;"> By using satellites and studying rocks, researchers observe the Earth's magnetic field, as well as the local and regional changes in magnetic strength. Background: The geomagnetic poles of the Earth—not to be confused with the geographic poles—are constantly moving. As a result of this movement they have actually changed positions with each other every 200,000 to 300,000 years in the recent history of the Earth. The last poles flip happened 780,000 years ago, and last decades scientists report acceleration in the movement of the Earth magnetic poles. Flip of magnetic poles would have profound effect on modern human civilisation. Factors which control movements and flip of the magnetic poles, as well as directions they follow during overturn are not understood yet.<br /> <br /> One of the poles' routes observed during the flips runs over the western Pacific, corresponding very noticeably to the proposed electromagnetic sources in the Earth's mantle. The researchers are therefore considering the possibility that the magnetic fields observed in the Pacific with the aid of rock records do not represent the migration route of the poles measured on the Earth's surface, but originate from the hitherto unknown electromagnetic source of hematite-containing rocks in the Earth's mantle beneath the West Pacific.<br /> <br /> "What we now know—that there are magnetically ordered materials down there in the Earth's mantle—should be taken into account in any future analysis of the Earth's magnetic field and of the movement of the poles," says co-author Prof. Leonid Dubrovinsky at the Bavarian Research Institute of Experimental Geochemistry and Geophysics at Bayreuth University.</div> <div style="text-align: left;"> <br /> <br /></div> <div style="text-align: left;"> <u><i><span style="font-family: "trebuchet ms" , sans-serif;">The above story is based on <a href="https://www.uni-muenster.de/news/view.php?cmdid=10326&lang=en" rel="nofollow" target="_blank">materials </a>provided by the  <a href="https://www.uni-muenster.de/en/" rel="nofollow" target="_blank">University of Münster.</a></span></i></u></div> </div>

Magnetism Discovered in the Earth's Mantle

The interior of the Earth and the experiment graphically illustrated. The blue dotted lines show the magnetic field surrounding the Earth...

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New Mineral Classification System Captures Earth's Complex Past

<div dir="ltr" style="text-align: left;" trbidi="on"> <table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody> <tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-cmYtZsmqmZc/XPkrL-ngA8I/AAAAAAAAREY/e1QAgr5vrFIdg1kSObvq16Rts7gUw5mnwCLcBGAs/s1600/New%2BMineral%2BClassification%2BSystem%2BCaptures%2BEarth%2527s%2BComplex%2BPast.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="New Mineral Classification System Captures Earth's Complex Past" border="0" data-original-height="1080" data-original-width="1080" height="640" src="https://1.bp.blogspot.com/-cmYtZsmqmZc/XPkrL-ngA8I/AAAAAAAAREY/e1QAgr5vrFIdg1kSObvq16Rts7gUw5mnwCLcBGAs/s640/New%2BMineral%2BClassification%2BSystem%2BCaptures%2BEarth%2527s%2BComplex%2BPast.jpg" title="" width="640" /></a></td></tr> <tr><td class="tr-caption" style="text-align: center;">Liddicoatite. Photo: Platonic Gems.</td></tr> </tbody></table> <br /> The first minerals to form in the universe were nanocrystalline diamonds, which condensed from gases ejected when the first generation of stars exploded. Diamonds that crystallize under the extreme pressure and temperature conditions deep inside of Earth are more typically encountered by humanity. What opportunities for knowledge are lost when mineralogists categorize both the cosmic travelers and the denizens of deep Earth as being simply "diamond"?<br /> <br /> Could a new classification system that accounts for minerals' distinct journeys help us better understand mineralogy as a process of universal and planetary evolution?<br /> <br /> The current system for classifying minerals -- developed by James Dwight Dana in the 1850s -- categorizes more than 5,400 mineral "species" based on their dominant chemical compositions and crystalline structures. This is an unambiguous, robust, and reproducible designation scheme.<br /> <br /> Carnegie's Robert Hazen suggests an additional classification system, which could amplify existing knowledge of how minerals evolve over time without superseding the existing designations. In American Mineralogist's Roebling Medal Paper, Hazen argues for categories that reflect a deeper, more-modern understanding of planetary scale transformation over time.<br /> <div style="margin: 0px auto; width: 100%;"> <script async="" src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script><br /> <ins class="adsbygoogle" data-ad-client="ca-pub-1021498709184325" data-ad-format="fluid" data-ad-layout="in-article" data-ad-slot="6157425841" style="display: block; text-align: center;"></ins><br /> <script> (adsbygoogle = window.adsbygoogle || []).push({}); </script><br /></div> A system grouping minerals and non-crystalline natural solids -- which are not currently classified by the existing system -- into what Hazen calls "natural kind clusters" would better reflect the inherent messiness of planetary evolution, he explains.<br /> <br /> "For maximum efficacy, scientific classification systems must not just organize and define, but also reflect current theory, and allow it to expand and guide us to new conclusions," Hazen says.<br /> <br /> He pioneered the concept of mineral evolution -- linking an explosion in mineral diversity to the rise of life on Earth and the resulting oxygen-rich atmosphere. Hazen then added another layer to his vision by introducing mineral ecology -- which analyzes the spatial distribution of Earth's minerals to predict which ones remain undiscovered and to assert our planet's mineralogical uniqueness.<br /> <br /> A system of categorization that reflects not just a mineral's chemistry and crystalline structure, but also the physical, chemical, or biological processes by which it formed, would be capable of recognizing that nanodiamonds from space are fundamentally different to diamonds formed in Earth's depths.<br /> <br /> The existing classification system groups some minerals with disparate formation histories together in one category, while splitting others with similar origin stories into separate mineral species.<br /> <br /> Another example: currently 32 different mineral species of the "tourmaline group" are delineated by the distribution of the major elements of which they are comprised. So, a single shard of tourmaline with slight variations in chemistry often contains multiple species of the mineral, even if they all formed in the same geologic event.<br /> <br /> A natural kind classification system would rectify that problem, and allow for the inclusion of non-crystalline materials, such as volcanic glass, amber, and coal, which currently aren't counted as minerals, but can offer knowledge about our evolving planet.<br /> <br /> "Earth's mineralogy tells vivid stories, revealing how eons of geologic activity and the rise of life facilitated novel combinations of elements," Hazen argues. "But to glean every nuance of this mineralogical text, we must embrace a new language for describing the creation of minerals that reflects the passage of time."<br /> <br /> <br /> <br /> <u><i><span style="font-family: "trebuchet ms" , sans-serif;">The above story is based on <a href="https://carnegiescience.edu/news/new-mineral-classification-system-captures-earths-complex-past-0" rel="nofollow" target="_blank">Materials</a> provided by <a href="https://carnegiescience.edu/" rel="nofollow" target="_blank">Carnegie Institution for Science</a></span></i></u></div>

New Mineral Classification System Captures Earth's Complex Past

Liddicoatite. Photo: Platonic Gems. The first minerals to form in the universe were nanocrystalline diamonds, which condensed from gas...

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