Geology In

Texas Woman Finds 3.72-carat Diamond at Arkansas State Park

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<tr><td class="tr-caption" style="text-align: center;">The 3.72-carat diamond was smaller than a quarter. (Photo Credit: Arkansas State Parks)</td></tr>
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<span style="font-family: "georgia" , "times new roman" , serif;">A Texas woman on a first-time visit to Arkansas’ Crater of Diamonds State Park says she discovered a nearly 4-carat yellow diamond—while watching a YouTube video about how to find the precious gemstones.</span><br />
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According to a report on the discovery from the state parks website, Miranda Hollingshead, 27, decided to visit the park with family last week as something fun to do together. The park—where tens of thousands of individual diamonds have been found over the course of the last century—is situated just a couple of hours away from where Hollingshead lives in Bogata.<br />
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While surveying the park’s 37.5 acres of designated diamond discovery area, Hollingshead says she was “sitting in the shade, watching a YouTube video on how to find diamonds” when she spotted the massive 3.72-carat gemstone, noting that she “looked over at my kid for a second, and when I looked down, I saw it mixed in with other rocks.”<br />
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According to park interpreter Waymon Cox, the diamond—which was described as a light yellow color and about the size of a pencil eraser—was likely discovered as the result of recent rainfall.<br />
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“Much of the ground where Ms. Hollingshead found her diamond is made of unweathered volcanic rock,” Cox said in a statement. “When it rains, flowing runoff often leaves loose gravel, and sometimes diamonds, on the surface in these areas. Diamonds have a brilliant, adamantine luster that makes them easy to spot, and Ms. Hollingshead happened to be sitting in just the right place to see the diamond sparkle in the sun.”<br />
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<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-ExKy6jAB5IU/XV7ENaW6d-I/AAAAAAAARWg/q9NzJzrMoogARcP1e_EvNIe3EqDtJBYwwCLcBGAs/s1600/Texas%2BWoman%2BFinds%2B3.72-carat%2BDiamond%2Bat%2BArkansas%2BState%2BPark%2B%25281%2529.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="Texas Woman Finds 3.72-carat Diamond at Arkansas State Park" border="0" data-original-height="679" data-original-width="1207" height="360" src="https://1.bp.blogspot.com/-ExKy6jAB5IU/XV7ENaW6d-I/AAAAAAAARWg/q9NzJzrMoogARcP1e_EvNIe3EqDtJBYwwCLcBGAs/s640/Texas%2BWoman%2BFinds%2B3.72-carat%2BDiamond%2Bat%2BArkansas%2BState%2BPark%2B%25281%2529.jpg" title="" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The 3.72-carat diamond was smaller than a quarter. (Photo Credit: Arkansas State Parks)</td></tr>
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According to the state parks website, nearly 320 diamonds have been registered at Crater of Diamonds State Park this year, with 13 of those weighing at least carat. Combined, those diamonds make up a staggering 63.49 carats. Cox said Hollingshead described her diamond as reminiscent of “of a rounded molar, with a small indentation in one end.”<br />
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There are a ton of factors that go into appraising a diamond like the one that Hollingshead discovered, but it’s likely worth somewhere in the tens of thousands of dollars.<br />
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Assuming you have the time to hunch over and scour for diamonds across dozens of acres, Crater of Diamonds State Park sure seems to be a good place to find one. Just last month, 36-year-old Josh Lanik discovered a 2.12-carat diamond, the largest diamond discovery of the year at the time. In April, park visitor Glenn Worthington found a brown diamond weighing in at 1.52 carats.<br />
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<div class="pw-hidden-cp">
<span style="font-family: "georgia" , "times new roman" , serif;"><a href="https://www.geologyin.com/2016/08/the-only-diamond-mine-in-world-where.html" target="_blank">The Only Diamond Mine In the World Where You Can Be the Miner</a></span></div>
<span style="font-family: "georgia" , "times new roman" , serif;"><br />
<b>See also: </b><br />
<a href="https://www.geologyin.com/2016/09/top-spots-for-gem-hunting-in-us.html">Top Spots For Gem Hunting In The US I</a></span> <span style="font-family: "georgia" , "times new roman" , serif;"><a href="https://www.geologyin.com/2017/02/part-ii-top-spots-for-gem-hunting-in-us.html">Top Spots For Gem Hunting In The US II</a></span></div>

Texas Woman Finds 3.72-carat Diamond at Arkansas State Park

The 3.72-carat diamond was smaller than a quarter. (Photo Credit: Arkansas State Parks) A Texas woman on a first-time visit to Arkan...

A Tectonic Plate is Dying Under Oregon

Geology, Tectonic, USA 7:53 PM

A Tectonic Plate is Dying Under Oregon

The Juan de Fuca plate meets the North American plate beneath the Cascadia fault. USGS, CC BY A gaping hole in a dying tectonic plate...

Ancient 'Lava Reservoir' and Diamonds as Old as the Moon Have Been Found

Diamonds, Earth History, Geology 6:46 PM

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<tr><td class="tr-caption" style="text-align: center;">Diamonds from the Juina area: most of these are superdeep diamonds. Credit: Graham Pearson</td></tr>
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A careful inspection of super-deep diamonds has revealed what geologists have long suspected: Hiding somewhere in our planet's interior, there exists a vast reservoir of primordial magma, undisturbed for more than 4 billion years.<br />
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Analyses show that gases found in microscopic inclusions in diamonds come from a stable subterranean reservoir at least as old as the Moon, hidden more than 410 km below sea level in the Earth's mantle.<br />
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Scientists have long suspected that an area of the Earth's mantle, somewhere between the crust and the core, contains a vast reservoir of rock, comparatively undisturbed since the planet's formation. Until now, there has been no firm proof if or where it exists. Now an international group of scientists has measured helium isotopes contained in superdeep diamonds brought to the surface by violent volcanic eruptions, to detect the footprints of this ancient reservoir. <br />
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After the formation of the Earth, violent geological activity and extra-terrestrial impacts disrupted the young planet, meaning that almost nothing of the Earth's original structure remains. Then in the 1980's geochemists noted that in some basalt lavas from particular locations the ratio of the helium 3 to helium 4 isotope was higher than expected, mirroring the isotope ratio found in extremely old meteorites which had fallen to Earth. <br />
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This indicates that the lava had carried the material from some kind of reservoir deep in the Earth, with a composition which hasn't changed significantly in the last 4 billion years. "This pattern has been observed in "Ocean Island Basalts," which are lavas coming to the surface from deep in the Earth, and form islands such as Hawaii and Iceland" said research leader Dr. Suzette Timmerman, from the Australian National University. "The problem is that although these basalts are brought to the surface, we only see a glimpse of their history. We don't know much about the mantle where their melts came from."<br />
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To address this problem, Timmerman's team looked at helium isotope ratios in superdeep diamonds. Most diamonds are formed between 150 to 230 km below the Earth's crust, before being carried to the surface by melts. Very occasionally some 'superdeep' diamonds (created between 230 and 800 km below the Earth's surface) are brought to the surface. These superdeep diamonds are recognizably different from normal diamonds.<br />
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Suzette Timmerman said, "Diamonds are the hardest, most indestructible natural substance known, so they form a perfect time capsule that provides us a window into the deep Earth. We were able to extract helium gas from twenty-three super-deep diamonds from the Juina area of Brazil.<br />
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These showed the characteristic isotopic composition that we would expect from a very ancient reservoir, confirming that the gases are remnants of a time at or even before the Moon and Earth collided. From the geochemistry of the diamonds, we know that they formed in an area called the "transition zone," which is between 410 and 660 km below the surface of the Earth. This means that this unseen reservoir, left over from the Earth's beginnings, must be in this area or below it.<br />
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"Questions remain about the form of this reservoir; is it a large single reservoir, or are there multiple smaller ancient reservoirs? Where exactly is the reservoir? What is the complete chemical composition of this reservoir? But with this work, we are beginning to home in on what is probably the oldest remaining comparatively undisturbed material on Earth," she says.<br />
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Commenting, Professor Matthew Jackson (University of California, Santa Barbara) said, "There has been a lot of work focused on identifying the location of primordial reservoirs in the deep Earth. So this is an interesting result, with a lot of potential to "map out" where elevated 3He/4He domains are located in the Earth's deep interior.<br />
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Helium can diffuse rapidly at mantle conditions, so it will be important to evaluate whether the ancient helium signature reflects compositions trapped at diamond-formation depths, or the composition of the host lava that transported to diamonds to the surface. This work is an important step towards understanding these reservoirs, and points the way to further research."<br />
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<u><i><span style="font-family: "trebuchet ms" , sans-serif;">The findings have been published in <a href="https://science.sciencemag.org/cgi/doi/10.1126/science.aax5293">Science</a>.</span></i></u></div>

Ancient 'Lava Reservoir' and Diamonds as Old as the Moon Have Been Found

Diamonds from the Juina area: most of these are superdeep diamonds. Credit: Graham Pearson A careful inspection of super-deep diamond...

These 54-Million-Year-Old Fly Eyes Are Preserved in Astounding Detail

Earth History, Fossils 7:43 PM

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<tr><td class="tr-caption" style="text-align: center;">Eyes surprise: fossil eyes from a 54 million year old cranefly. Lindgren et al./Nature</td></tr>
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<span style="font-family: Georgia, "Times New Roman", serif;">Composition of fossil insect eyes surprises researchers</span></h4>
<span style="font-family: "georgia" , "times new roman" , serif;">Fossilised flies that lived 54 million years ago have revealed a surprising twist to the tale of how insects’ eyes evolved. These craneflies, unveiled in Nature today, show that insect eyes trap light the same way as human eyes, using the pigment melanin – yet another example of evolution finding similar solutions to similar problems.</span><br />
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"We were surprised by what we found because we were not looking for, or expecting it," says Johan Lindgren, an Associate Professor at the Department of Geology, Lund University, and lead author of the study published this week in the journal Nature.<br />
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The researchers went on to examine the eyes of living crane-flies, and found additional evidence for eumelanin in the modern species as well.<br />
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By comparing the fossilized eyes with optic tissues from living crane-flies, the researchers were able to look closer at how the fossilization process has affected the conservation of compound eyes across geological time.<br />
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The fossilized eyes further possessed calcified ommatidial lenses, and Johan Lindgren believes that this mineral has replaced the original chitinous material.<br />
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This, in turn, led the researchers to conclude that another widely held hypothesis may need to be reconsidered. Previous research has suggested that trilobites -- an exceedingly well-known group of extinct seagoing arthropods -- had mineralized lenses in life.<br />
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"The general view has been that trilobites had lenses made from single calcium carbonate crystals. However, they were probably much more similar to modern arthropods in that their eyes were primarily organic," says Johan Lindgren.<br />
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Compound eyes are found in arthropods, such as insects and crustaceans, and are the most common visual organ seen in the animal kingdom. They are made up of multiple tiny and light-sensitive ommatidia, and the perceived image is a combination of inputs from these individual units.<br />
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<h4 style="text-align: left;">
<span style="font-family: "georgia" , "times new roman" , serif;">Eyes like our own?</span></h4>
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However, detailed chemical analysis of the fossil cranefly eyes revealed that they contained human-like melanin. When the researchers had another look at the eyes of living craneflies, they were surprised to confirm the presence of melanin (as well as lots of ommochrome). It took fossils to alert us that the eyes of humans and insects both use the same shielding pigments (melanin) - yet another example of convergent evolution.<br />
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Intriguingly, the outer layers of the fossilised eyes were full of calcite, the mineral that makes up most of limestone. Not only that, but crystals in the calcite were aligned to transmit light efficiently into the eye. Yet this apparent fine engineering (a mineralised outer eye layer optimised to transmit light) was almost certainly caused by the fossilisation process, as the eyes of living craneflies are not mineralised.<br />
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While the fossil record can reveal, it can also mislead, if not interpreted carefully. Trilobites, the hard-shelled crab-like creatures that are among the most abundant and diverse animal fossils, are frequently found with mineralised, light-transmitting outer eye layers. These have usually been assumed to faithfully reflect their life condition: predation in ancient oceans was so intense that trilobites even armoured their eyeballs.<br />
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Lindgren and colleagues warn against this interpretation: perhaps the trilobite’s “protective goggles” only appeared after fossilisation, just as in the craneflies. However, this interpretation will likely be debated. Trilobite eyes seem to have been unusually rigid and resilient in real life, as they are preserved in three dimensions much more often than eyes of other animals. They also have certain optical properties that make more sense when the rigid outer layer is accepted as real.<br />
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A disagreement between a few palaeontologists might seem a bit arcane, but these debates can have real-world relevance. Most famously, the concept of nuclear winter was directly inspired by discussion of how the dinosaurs went extinct, when a meteorite impact enveloped the world in a cloud of dust, deep-freezing the entire biosphere.<br />
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Granted, the debate over how insect and trilobite eyes functioned is unlikely to influence world peace, but it might still have useful applications. For example, the way trilobite lenses (apparently) provide constant acuity while being totally rigid has inspired bioengineers to fashion high-performance optical devices with uses spanning microscopy to laser physics.</div>
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<i><u><span style="font-family: "trebuchet ms" , sans-serif;">The above story is based on <a href="https://www.lunduniversity.lu.se/article/the-composition-of-fossil-insect-eyes-surprises-researchers" rel="nofollow" target="_blank">Materials</a> provided by <a href="https://www.lunduniversity.lu.se/" rel="nofollow" target="_blank">Lund University</a>. </span></u></i><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>

These 54-Million-Year-Old Fly Eyes Are Preserved in Astounding Detail

Eyes surprise: fossil eyes from a 54 million year old cranefly. Lindgren et al./Nature Composition of fossil insect eyes surprises r...

New Zealand Scientists Discover Fossilized Bones of Human-sized 'Monster Penguin'

Earth History, Fossils 7:07 PM

New Zealand Scientists Discover Fossilized Bones of Human-sized 'Monster Penguin'

Dr. Paul Scofield, senior curator natural history at Canterbury Museum, holds the fossil, a tibiotarsus, left, next to a similar bone of ...

Tiger Eye Stone Effects

gemstones, Mineralogy 7:51 PM

Tiger Eye Stone Effects

Set of various tiger-eye natural mineral stones and gemstones (tigers eye, bull-eye, hawk-eye). Copyright : vvoennyy Tiger's eye...

Earth's Magnetic Field Reversals May Take Much Longer Than We Thought

Earth History, Earth's magnetic field, Researches 7:16 PM

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Earth's Magnetic Field Went Completely Haywire During Last Reversal and Took 22,000 Years to Get Back to Normal<br />
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Yet, largely hidden from daily life, the field drifts, waxes and wanes. The magnetic North Pole is currently careening toward Siberia, which recently forced the Global Positioning System that underlies modern navigation to update its software sooner than expected to account for the shift.<br />
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And every several hundred thousand years or so, the magnetic field dramatically shifts and reverses its polarity: Magnetic north shifts to the geographic South Pole and, eventually, back again. This reversal has happened countless times over the Earth's history, but scientists have only a limited understanding of why the field reverses and how it happens.<br />
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New work from University of Wisconsin-Madison geologist Brad Singer and his colleagues finds that the most recent field reversal, some 770,000 years ago, took at least 22,000 years to complete. That's several times longer than previously thought, and the results further call into question controversial findings that some reversals could occur within a human lifetime.<br />
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The new analysis -- based on advances in measurement capabilities and a global survey of lava flows, ocean sediments and Antarctic ice cores -- provides a detailed look at a turbulent time for Earth's magnetic field. Over millennia, the field weakened, partially shifted, stabilized again and then finally reversed for good to the orientation we know today.<br />
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The results provide a clearer and more nuanced picture of reversals at a time when some scientists believe we may be experiencing the early stages of a reversal as the field weakens and moves. Other researchers dispute the notion of a present-day reversal, which would likely affect our heavily electronic world in unusual ways.<br />
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Singer published his work Aug. 7 in the journal Science Advances. He collaborated with researchers at Kumamoto University in Japan and the University of California, Santa Cruz.<br />
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"Reversals are generated in the deepest parts of the Earth's interior, but the effects manifest themselves all the way through the Earth and especially at the Earth's surface and in the atmosphere," explains Singer. "Unless you have a complete, accurate and high-resolution record of what a field reversal really is like at the surface of the Earth, it's difficult to even discuss what the mechanics of generating a reversal are."<br />
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Earth's magnetic field is produced by the planet's liquid iron outer core as it spins around the solid inner core. This dynamo action creates a field that is most stable going through roughly the geographic North and South poles, but the field shifts and weakens significantly during reversals.<br />
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As new rocks form -- typically either as volcanic lava flows or sediments being deposited on the sea floor -- they record the magnetic field at the time they were created. Geologists like Singer can survey this global record to piece together the history of magnetic fields going back millions of years. The record is clearest for the most recent reversal, named Matuyama-Brunhes after the researchers who first described reversals.<br />
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For the current analysis, Singer and his team focused on lava flows from Chile, Tahiti, Hawaii, the Caribbean and the Canary Islands. The team collected samples from these lava flows over several field seasons.<br />
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"Lava flows are ideal recorders of the magnetic field. They have a lot of iron-bearing minerals, and when they cool, they lock in the direction of the field," says Singer. "But it's a spotty record. No volcanoes are erupting continuously. So we're relying on careful field work to identify the right records."<br />
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The researchers combined magnetic readings and radioisotope dating of samples from seven lava flow sequences to recreate the magnetic field over a span of about 70,000 years centered on the Matuyama-Brunhes reversal. They relied on upgraded methods developed in Singer's WiscAr geochronology lab to more accurately date the lava flows by measuring the argon produced from radioactive decay of potassium in the rocks.<br />
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They found that the final reversal was quick by geological standards, less than 4,000 years. But it was preceded by an extended period of instability that included two excursions -- temporary, partial reversals -- stretching back another 18,000 years. That span is more than twice as long as suggested by recent proposals that all reversals wrap up within 9,000 years.<br />
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The lava flow data was corroborated by magnetic readings from the seafloor, which provides a more continuous but less precise source of data than lava rocks. The researchers also used Antarctic ice cores to track the deposition of beryllium, which is produced by cosmic radiation colliding with the atmosphere. When the magnetic field is reversing, it weakens and allows more radiation to strike the atmosphere, producing more beryllium.<br />
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Since humanity began recording the strength of the magnetic field, it has decreased in strength about five percent each century. As records like Singer's show, a weakening field seems to be a precursor to an eventual reversal, although it's far from clear that a reversal is imminent.<br />
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A reversing field might significantly affect navigation and satellite and terrestrial communication. But the current study suggests that society would have generations to adapt to a lengthy period of magnetic instability.<br />
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"I've been working on this problem for 25 years," says Singer, who stumbled into paleomagnetism when he realized the volcanoes he was studying served as a good record of Earth's magnetic fields. "And now we have a richer record and better-dated record of this last reversal than ever before."<br />
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<br />
<u><i><span style="font-family: "trebuchet ms" , sans-serif;">The above story is based on <a href="https://news.wisc.edu/earths-last-magnetic-field-reversal-took-far-longer-than-once-thought/" rel="nofollow" target="_blank">Materials</a> provided by <a href="http://www.wisc.edu/" rel="nofollow" target="_blank">University of Wisconsin-Madison</a>. Original written by Eric Hamilton.</span></i></u></div>

Earth's Magnetic Field Reversals May Take Much Longer Than We Thought

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Hidden Water Found on Hawaii’s Kilauea Could Mean Explosive Eruptions

Hawaii, volcano 7:21 PM

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<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-IyPmaFbIAwU/XUr3vZ_PdUI/AAAAAAAARTU/1GYQfQTs1no5G_CFk5eJ3Zqf5YdUK7duACLcBGAs/s1600/Lava%2Berupts%2Bfrom%2Ba%2BKilauea%2Bvolcano%2Bfissure%2Bin%2BLeilani%2BEstates%2B%25281%2529.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="Lava erupts from a Kilauea volcano fissure in Leilani Estates, on Hawaii's Big Island, on May 24, 2018, in Pahoa." border="0" data-original-height="677" data-original-width="1203" height="360" src="https://1.bp.blogspot.com/-IyPmaFbIAwU/XUr3vZ_PdUI/AAAAAAAARTU/1GYQfQTs1no5G_CFk5eJ3Zqf5YdUK7duACLcBGAs/s640/Lava%2Berupts%2Bfrom%2Ba%2BKilauea%2Bvolcano%2Bfissure%2Bin%2BLeilani%2BEstates%2B%25281%2529.jpg" title="" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Lava erupts from a Kilauea volcano fissure in Leilani Estates, on Hawaii's Big Island, on May 24, 2018, in Pahoa.</td></tr>
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<h4 style="text-align: left;">
<span style="font-family: "georgia" , "times new roman" , serif;">Water was found for the first time in Hawaii's Kilauea volcano, and it could trigger explosive eruptions</span></h4>
Hawaii's Kilauea volcano, which just quieted down after a 30-year active stint, harbors a previously unknown patch of water at the bottommost part of its crater, according to the U.S. Geological Survey. And it might have the potential to trigger explosive eruptions in the future.<br />
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For the first time in recorded history, a pond of water has been discovered inside the summit crater of Hawaii’s Kilauea volcano, a development that could signal a shift to a more explosive phase of future eruptions.<br />
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After a week of questions about a mysterious green patch at the bottom of the volcano’s Halemaumau crater, the former home of a famed lava lake, researchers confirmed the presence of water on Thursday, officials with the U.S. Geological Survey told the Associated Press on Friday.<br />
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“The question is what does this mean in the evolution of the volcano?” USGS scientist emeritus Don Swanson said.<br />
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Halemaumau has never had water since written observations began, he said, so the pond is unusual.<br />
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Scientists aren’t exactly certain what will happen next but when lava interacts with water it can cause explosive eruptions.<br />
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One possibility is that lava could slowly heat up the groundwater and eventually create a new lava lake, Swanson said. Lava could also interact with the water table and create small explosions.<br />
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“The other possibility is that magma rises rapidly,” Swanson said. “That could produce a larger explosion.”<br />
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USGS officials stressed that there is currently “no reason to think hazards at the summit have increased or decreased” because of the discovery of water.<br />
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<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/-pFRv9U5VKkE/XUr56iBlowI/AAAAAAAARTg/-kZp6XuM6eUV67gObmWto2i73FYzyCjugCLcBGAs/s1600/water-hawaii-kilauea-volcano%2B%25281%2529%2B%25281%2529.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="The Main Pond of Water at the Bottom of Halemaumau as Captured on Sunday, August 4." border="0" data-original-height="605" data-original-width="1290" height="300" src="https://1.bp.blogspot.com/-pFRv9U5VKkE/XUr56iBlowI/AAAAAAAARTg/-kZp6XuM6eUV67gObmWto2i73FYzyCjugCLcBGAs/s640/water-hawaii-kilauea-volcano%2B%25281%2529%2B%25281%2529.jpg" title="" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The Main Pond of Water at the Bottom of Halemaumau as Captured on Sunday, August 4.<br /></td></tr>
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But Swanson said in June that the presence of water could be a significant switch in the long-term activity of the volcano.<br />
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Kilauea has a history of alternating between long periods of explosive eruptions and times of slower, so-called effusive phases.<br />
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Explosive periods are exactly what they sound like, centuries of massive explosions that send hot debris racing down the hillsides and towering columns of rock and ash high into the atmosphere.<br />
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Effusive periods, which Kilauea has been in for about 200 years, are marked by slower, steady lava flows that — in comparison — trickle out of the ground.<br />
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The next explosive period, researchers believe, will be preceded by a massive collapse of Kilauea’s caldera floor.<br />
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An eruption that was ongoing for more than 30 years came to a dramatic end last year when lava exploded from Kilauea’s flank and covered a huge swath of land, destroying hundreds of homes in one of the largest eruptions in recent history.<br />
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That eruption came with a significant drop of the caldera floor. Halemaumau crater collapsed nearly 2,000 feet over the course of several months but Swanson said he would expect a larger, “sort of wholesale collapse of the caldera floor” to trigger a prolonged explosive period.<br />
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“If it really is a transition then there will have to be repeated collapses, ever-deepening the caldera floor, before we would get into one of these larger scale events,” Swanson said.<br />
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Swanson said that while researchers have never observed water on the caldera floor before, there are Native Hawaiian chants that describe the presence of ponds appearing just before explosive events.<br />
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“It’s really not scientific evidence but it nonetheless enhances the interpretation,” Swanson said.<br />
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Researchers have data going back about 2,500 years that shows this transition between explosive and effusive stages.<br />
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“We know from mapping the deposits and studying them that there have been several of those (explosive) events between about 1,500 and 1,790 and several events between about 200 B.C. and 1,000 A.D.,” Swanson said. “Kilauea is the only volcano for which we’ve recognized these cycles so far and I think that’s because it’s been so intensively studied.”<br />
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These long periods are marked by large explosions that occur every few decades — or even centuries — with smaller explosions in between, Swanson said. And while explosive eruptions don’t normally feature fast-moving lava flows or massive fountains of molten rock, they are still very dangerous.<br />
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Swanson said big explosive eruptions commonly produce pyroclastic surges — walls of hot air, ash and rock. In 1790 one such eruption killed a large number of people at Kilauea’s caldera, Swanson said.<br />
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“These surges can move at hurricane velocity across the landscape and they are among the most dangerous kinds of eruptions,” he said.<br />
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Swanson said none of this will happen overnight, and he hopes that modern monitoring techniques will give the public plenty of warning.<br />
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“I’ve been stressing that the current activity at Kilauea, or lack thereof, can go either way,” Swanson said. “We can either return to what was going on before, or this could be the preamble to some more significant change in the volcano that leads to explosive activity.”<br />
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<br />
<i><u><span style="font-family: "trebuchet ms" , sans-serif;">The above story is based on <a href="https://www.apnews.com/" rel="nofollow" target="_blank">materials </a>provided by <a href="https://volcanoes.usgs.gov/observatories/hvo/hvo_volcano_watch.html?vwid=1423" rel="nofollow" target="_blank">USGS</a>. </span></u></i></div>

Hidden Water Found on Hawaii’s Kilauea Could Mean Explosive Eruptions

Lava erupts from a Kilauea volcano fissure in Leilani Estates, on Hawaii's Big Island, on May 24, 2018, in Pahoa. Water was foun...

Dinosaur Feathers Evolved for Sexual Display

dinosaur, Earth History 7:31 PM

Dinosaur Feathers Evolved for Sexual Display

A flightless dinosaur called Similicaudipteryx uses its feathers in a mating display. U of A researchers looked at how such displays may ...